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List of DDT Observations

Please note that obs_start_time is in UT, not local time.

Clicking on the Sequence Number link will take you to the title and abstract of the proposal.

Clicking on the ObsID link will take you to the results of our search in ADS for articles we were able to link to the ObsID. Our database extends to publications that appeared three months or more ago and does not include meeting abstracts.

A 'D' in the prop_time column means a proprietary time of 1-3 months, with the default being 3 months. A '3' means a proprietary time of three months. An 'N' means the data is public.

Click here for table only

Cycle	Sequence Number	ObsID	Instrument	Grating	Approved Exposure Time	Actual Exposure Time	Target	Status	Start Time [UT]	Proprietary Time	PI Name
10	200656	12009	ACIS-S	NONE	25.000000	0.000000	V838Mon	unobserved		N	Kastner
10	701973	10921	ACIS-S	NONE	5.000000	5.046400	2XMMJ130200.1+27465	archived	Jun 27 2009 3:28AM	N	Watson
10	501174	10929	ACIS-I	NONE	20.000000	20.134400	PSRJ1622-49	archived	Jul 10 2009 7:43AM	3	Rea
10	401125	11803	HRC-I	NONE	10.000000	10.156982	ESO243-49HLX-1	archived	Aug 17 2009 12:41PM	N	Farrell
10	401124	11802	ACIS-S	NONE	5.000000	5.035200	NGC6440X-2	archived	Aug 10 2009 8:26AM	N	Heinke
10	401066	10919	HRC-I	NONE	1.000000	1.175675	ESO243-49HLX-1	archived	Jul 4 2009 2:15PM	N	Farrell
10	401065	10907	ACIS-S	NONE	20.000000	18.448100	GROJ1655-40	archived	Jun 8 2009 2:46AM	N	Gallo
09	701771	9814	ACIS-S	NONE	10.000000	9.907200	SDSSJ0952+2143	archived	Feb 5 2008 4:43PM	N	Komossa
09	501152	10573	ACIS-S	NONE	10.000000	10.152500	GRB080307	archived	Sep 22 2008 8:36AM	N	Page
09	501018	9862	ACIS-S	NONE	30.000000	30.147200	SHB080503	archived	May 25 2008 6:28PM	N	Butler
09	501017	9853	ACIS-S	NONE	30.000000	30.175400	SHB080503	archived	May 7 2008 7:35PM	N	Butler
09	501014	9798	ACIS-S	NONE	18.500000	18.544200	SN2007on	archived	Dec 24 2007 11:15AM	D	Roelofs
09	501014	9799	ACIS-S	NONE	21.500000	21.569800	SN2007on	archived	Dec 27 2007 1:35AM	D	Roelofs
09	401051	10574	HRC-I	NONE	5.000000	5.162669	XTEJ1701-407	archived	Aug 26 2008 8:24PM	D	Kaplan
09	401050	10571	HRC-I	NONE	1.000000	1.183875	VPuppis	archived	Sep 1 2008 1:40AM	N	Maccarone
09	400934	9883	ACIS-S	NONE	10.000000	10.198400	XMMUJ005510.7-37385	archived	Jul 8 2008 9:26PM	N	Kong
09	400933	9882	ACIS-S	NONE	30.000000	30.180000	AXJ1754.2-2754	archived	Jul 15 2008 12:30AM	D	Keek
09	400932	9850	HRC-I	NONE	2.000000	2.186069	XTEJ1719-291	archived	Apr 27 2008 6:34PM	D	Sala
09	400931	9805	ACIS-S	NONE	5.000000	5.175000	m81-ot071213	archived	Dec 21 2007 6:54PM	D	Jonker
09	200569	10845	ACIS-S	NONE	40.000000	40.134400	ZCMa	archived	Dec 28 2008 10:48PM	N	Stelzer
09	200568	10826	HRC-I	NONE	5.000000	4.978425	51Peg	archived	Dec 6 2008 12:52PM	N	Schmitt
09	200568	10825	ACIS-S	NONE	5.000000	4.982400	51Peg	archived	Dec 6 2008 11:21AM	N	Schmitt
09	200526	9768	ACIS-I	NONE	30.000000	28.154200	NGC2264field1	archived	Mar 12 2008 6:10PM	N	Micela
09	200526	9769	ACIS-I	NONE	30.000000	30.150559	NGC2264field1	archived	Mar 28 2008 3:02PM	N	Micela
08	900737	8591	ACIS-I	NONE	46.000000	46.034877	ChandraDeepField-S	archived	Sep 20 2007 5:41AM	N	Tananbaum
08	900737	8592	ACIS-I	NONE	88.000000	87.785596	ChandraDeepField-S	archived	Oct 22 2007 12:36PM	N	Tananbaum
08	900737	8593	ACIS-I	NONE	51.000000	50.145559	ChandraDeepField-S	archived	Oct 6 2007 2:22AM	N	Tananbaum
08	900737	8594	ACIS-I	NONE	151.200000	143.272414	ChandraDeepField-S	archived	Nov 1 2007 12:10PM	N	Tananbaum
08	900737	8595	ACIS-I	NONE	118.000000	116.950436	ChandraDeepField-S	archived	Oct 19 2007 2:35PM	N	Tananbaum
08	900737	8596	ACIS-I	NONE	118.000000	116.640477	ChandraDeepField-S	archived	Oct 24 2007 1:46PM	N	Tananbaum
08	900737	8597	ACIS-I	NONE	61.000000	60.068618	ChandraDeepField-S	archived	Oct 17 2007 7:23AM	N	Tananbaum
08	900737	9575	ACIS-I	NONE	112.400000	110.133372	ChandraDeepField-S	archived	Oct 27 2007 6:09AM	N	Tananbaum
08	900737	9578	ACIS-I	NONE	40.000000	39.084800	ChandraDeepField-S	archived	Oct 30 2007 10:53PM	N	Tananbaum
08	900737	9593	ACIS-I	NONE	48.000000	47.045600	ChandraDeepField-S	archived	Sep 22 2007 8:49PM	N	Tananbaum
08	900737	9596	ACIS-I	NONE	115.400000	113.372872	ChandraDeepField-S	archived	Nov 4 2007 4:30AM	N	Tananbaum
08	900737	9718	ACIS-I	NONE	51.000000	50.030737	ChandraDeepField-S	archived	Oct 3 2007 2:12PM	N	Tananbaum
08	701583	8517	ACIS-S	NONE	5.000000	5.153200	M87	archived	Mar 22 2007 4:06AM	N	Harris
08	701582	8516	ACIS-S	NONE	5.000000	5.159200	M87	archived	Mar 19 2007 10:38AM	N	Harris
08	701581	8515	ACIS-S	NONE	5.000000	5.177600	M87	archived	Mar 14 2007 2:43PM	N	Harris
08	701580	8514	ACIS-S	NONE	5.000000	4.929200	M87	archived	Mar 12 2007 11:52AM	N	Harris
08	701579	8513	ACIS-S	NONE	5.000000	5.182800	M87	archived	Feb 24 2007 3:16AM	N	Harris
08	701578	8512	ACIS-S	NONE	5.000000	5.185600	M87	archived	Feb 21 2007 11:58PM	N	Harris
08	701577	8511	ACIS-S	NONE	5.000000	5.185600	M87	archived	Feb 18 2007 10:23PM	N	Harris
08	701576	8510	ACIS-S	NONE	5.000000	5.183600	M87	archived	Feb 15 2007 9:37AM	N	Harris
08	600649	8524	ACIS-S	NONE	30.000000	30.041600	GRB070125	archived	Mar 5 2007 9:49PM	N	Frail
08	501009	9579	ACIS-I	NONE	20.000000	19.709759	SN2007gr	archived	Aug 29 2007 1:52AM	N	Soderberg
08	500822	8518	ACIS-S	NONE	3.000000	3.043200	SN2005kd	archived	Mar 4 2007 2:54PM	N	Pooley
08	500821	8508	HRC-I	NONE	2.000000	2.159931	1RXSJ141256.0+79220	archived	Feb 18 2007 6:05PM	D	Rutledge
08	500820	8506	ACIS-S	NONE	20.000000	20.182000	CXOJ164710.2-455216	archived	Feb 2 2007 7:26PM	N	Woods
08	400928	9584	HRC-I	NONE	2.000000	2.184531	M15	archived	Sep 5 2007 3:23PM	N	Heinke
08	400691	8564	ACIS-I	NONE	11.200000	11.152000	SWIFTJ1756.9-2508	archived	Jul 6 2007 1:44AM	N	DiSalvo
08	400690	8562	ACIS-S	HETG	10.000000	10.152500	SwiftJ195509.6+2614	archived	Jun 14 2007 6:17PM	D	KANBACH
08	400689	8556	HRC-I	NONE	7.000000	7.180382	CirX-1	archived	May 16 2007 9:11PM	D	Jonker
08	400688	8547	HRC-I	NONE	43.000000	43.290108	CirX-1	archived	Apr 21 2007 5:32AM	D	Jonker
08	100071	9755	ACIS-S	NONE	10.000000	10.137600	17P/Holmes	archived	Oct 31 2007 10:31AM	N	Dennerl
08	100071	9762	ACIS-S	NONE	10.000000	10.188800	17P/Holmes	archived	Oct 31 2007 1:26PM	N	Dennerl
08	100071	9763	ACIS-S	NONE	10.000000	10.179200	17P/Holmes	archived	Oct 31 2007 4:21PM	N	Dennerl
07	600607	7373	ACIS-S	NONE	7.000000	7.184000	XMMUJ132218.3-16424	archived	Jul 31 2006 3:41AM	N	Miniutti
07	500817	8480	HRC-I	NONE	1.000000	1.149025	RBS1774(1RXSJ214303	archived	Nov 26 2006 10:15PM	D	Zane
07	500816	8473	ACIS-S	NONE	30.000000	30.124800	SN2006gy	archived	Nov 14 2006 8:57PM	N	Pooley
07	500815	8457	ACIS-S	NONE	10.000000	9.961600	SN2006jc	archived	Nov 4 2006 6:23AM	N	Immler
07	500814	8455	ACIS-S	NONE	15.000000	15.186750	CXOJ164710.2-455216	archived	Oct 28 2006 7:19AM	D	Kas
07	500693	7277	ACIS-S	NONE	15.000000	14.998400	SN2005ke	archived	Feb 19 2006 11:11AM	N	Immler
07	500692	7276	HRC-I	NONE	1.000000	1.112125	IGRJ15359-5750	archived	Mar 28 2006 4:54AM	N	Israel
07	500691	7275	HRC-I	NONE	1.000000	1.122631	IGRJ18048-1544	archived	Mar 28 2006 4:10AM	N	Israel
07	500690	7274	HRC-I	NONE	1.000000	1.097006	IGRJ17513-2011	archived	Mar 28 2006 3:40AM	N	Israel
07	500689	7273	HRC-I	NONE	1.000000	1.095981	IGRJ17488-3253	archived	Mar 28 2006 3:07AM	N	Israel
07	400680	8273	ACIS-I	NONE	21.600000	20.030359	LSI+61303	archived	Oct 25 2006 10:32PM	N	Perez-Torres
07	400561	7335	ACIS-S	NONE	10.000000	9.376000	PSRB1931+24	archived	Jul 20 2006 3:01PM	D	Rea
07	400559	7272	HRC-I	NONE	2.000000	2.135331	SWIFTJ1626.6-5156	archived	Feb 21 2006 6:28AM	N	Homan
07	400558	7269	ACIS-S	NONE	1.000000	1.161600	HD109962	archived	Feb 2 2006 2:14PM	N	Walter
07	300179	7298	HRC-S	LETG	20.000000	20.126132	RSOph	archived	Jun 4 2006 12:25PM	N	Starrfield
07	300178	7297	HRC-S	LETG	10.000000	9.505082	RSOph	archived	Apr 20 2006 5:43PM	N	Starrfield
07	300177	7296	HRC-S	LETG	10.000000	10.152882	RSOph	archived	Mar 24 2006 12:40PM	N	Starrfield
07	300172	7280	ACIS-S	HETG	10.000000	10.075000	RSOph	archived	Feb 26 2006 3:36PM	N	Starrfield
07	200460	8474	ACIS-I	NONE	10.000000	9.753600	L1415EXor	archived	Nov 18 2006 2:41AM	N	Kastner
07	100067	7334	ACIS-S	NONE	4.000000	4.182400	73P/Schwassmann-Wach	archived	May 23 2006 10:34AM	N	Wolk
07	100066	7333	ACIS-S	NONE	4.000000	4.182400	73P/Schwassmann-Wach	archived	May 23 2006 9:19AM	N	Wolk
07	100065	7332	ACIS-S	NONE	4.000000	4.185600	73P/Schwassmann-Wach	archived	May 23 2006 8:03AM	N	Wolk
07	100064	7331	ACIS-S	NONE	4.000000	4.185600	73P-B/Schwassmann-Wa	archived	May 23 2006 6:48AM	N	Wolk
07	100063	7330	ACIS-S	NONE	4.000000	4.105600	73P-B/Schwassmann-Wa	archived	May 23 2006 5:33AM	N	Wolk
06	701180	6278	ACIS-I	NONE	3.500000	3.638000	IGRJ19473+4452	archived	Jul 31 2005 9:32AM	N	Sunyaev
06	701179	6277	ACIS-I	NONE	3.500000	3.759572	IGRJ13091+1137	archived	Jul 25 2005 10:25AM	N	Sunyaev
06	701178	6276	ACIS-I	NONE	3.500000	3.260449	IGRJ12391-1612	archived	Jul 25 2005 11:45AM	N	Sunyaev
06	701177	6275	ACIS-I	NONE	3.500000	3.260799	IGRJ12026-5349	archived	Jun 16 2005 6:10AM	N	Sunyaev
06	701176	6274	ACIS-I	NONE	3.500000	3.676799	IGRJ11085-5100	archived	Jul 1 2005 3:58AM	N	Sunyaev
06	701175	6273	ACIS-I	NONE	3.500000	3.707715	IGRJ10252-6829	archived	Jul 30 2005 9:24AM	N	Sunyaev
06	701174	6272	ACIS-I	NONE	3.500000	3.257599	IGRJ07563-4137	archived	Jun 16 2005 4:46AM	N	Sunyaev
06	701173	6271	ACIS-I	NONE	3.500000	3.459199	IGRJ05007-7047	archived	Jun 16 2005 3:25AM	N	Sunyaev
06	701172	6227	ACIS-S	NONE	10.000000	10.323190	NGC3690	archived	Feb 14 2005 4:53AM	N	Nandra
06	500685	7241	ACIS-S	NONE	50.000000	50.179190	SN2005gj	archived	Dec 11 2005 5:26PM	N	Pooley
06	500603	6284	ACIS-S	NONE	30.000000	29.788040	SN2005bx	archived	Jul 30 2005 11:11AM	N	Filippenko
06	500601	6269	ACIS-S	NONE	20.000000	20.184090	GRB050412	archived	Apr 17 2005 9:43AM	N	Berger
06	500599	6251	HRC-S	NONE	30.000000	27.149430	SGR1806-20	archived	Apr 22 2005 7:03PM	D	Kouveliotou
06	500598	6224	ACIS-I	NONE	20.000000	19.059190	SGR1806-20	archived	Feb 9 2005 7:25AM	1	Fox
06	500597	6207	ACIS-S	NONE	30.000000	29.100500	SGR1806-20	archived	Feb 8 2005 10:54PM	1	Rea
06	400472	6354	ACIS-S	NONE	20.000000	19.043960	GRB050709	archived	Jul 25 2005 9:03PM	N	Frail
06	400470	6298	HRC-I	NONE	5.000000	4.767531	SAXJ1808.4-3658	archived	Jun 20 2005 11:25PM	N	Chakrabarty
06	400469	6297	ACIS-S	HETG	15.000000	14.344000	SAXJ1808.4-3658	archived	Jun 12 2005 2:32AM	N	Galloway
06	400468	6261	ACIS-S	NONE	10.000000	10.180800	J1638-4725	archived	May 4 2005 7:47PM	N	McLaughlin
06	400467	6259	ACIS-S	NONE	5.000000	5.169599	HESSJ1826-148	archived	Apr 13 2005 3:01AM	N	Funk
06	400447	6181	ACIS-S	NONE	15.000000	14.182800	IGRJ00291+5934	archived	Feb 6 2005 1:45PM	N	Jonker
06	400446	6180	ACIS-S	NONE	10.000000	9.894359	IGRJ00291+5934	archived	Jan 14 2005 12:11AM	N	Jonker
06	400445	6179	ACIS-S	NONE	5.000000	5.185200	IGRJ00291+5934	archived	Jan 1 2005 9:24PM	N	Jonker
06	300171	7186	ACIS-S	HETG	50.000000	50.155000	RTCru	archived	Oct 19 2005 10:41AM	N	Sokoloski
06	200372	6375	HRC-I	NONE	5.000000	5.150881	AlphaCentauri	archived	Dec 17 2006 4:58AM	N	Ayres
06	200371	6374	HRC-I	NONE	5.000000	5.157031	AlphaCentauri	archived	May 12 2006 6:31PM	N	Ayres
06	200370	6373	HRC-I	NONE	5.000000	5.187781	AlphaCentauri	archived	Oct 21 2005 2:59AM	N	Ayres
06	200363	6204	ACIS-S	NONE	5.000000	5.136400	V1118Ori	archived	Jan 26 2005 3:24AM	D	Audard
05	800560	6112	ACIS-I	NONE	10.000000	9.510799	MACS1427.2+4407	archived	Feb 12 2005 2:19AM	N	Allen
05	800559	6111	ACIS-I	NONE	50.000000	50.157877	MACS0744.9+3927	archived	Dec 3 2004 9:25PM	N	Allen
05	800558	6110	ACIS-I	NONE	70.000000	64.042810	MACS1311.0-0311	archived	Apr 20 2005 12:23AM	N	Allen
05	800557	6109	ACIS-I	NONE	40.000000	38.046250	MACS1621.6+3810	archived	Dec 11 2004 2:31PM	N	Allen
05	800557	6172	ACIS-I	NONE	30.000000	30.144270	MACS1621.6+3810	archived	Dec 25 2004 10:04PM	N	Allen
05	800556	6108	ACIS-I	NONE	40.000000	40.169750	MACS0329.7-0212	archived	Dec 6 2004 6:18AM	N	Allen
05	800555	6107	ACIS-I	NONE	38.000000	34.332410	MACS1720.3+3536	archived	Nov 22 2005 9:35PM	N	Allen
05	800555	7225	ACIS-I	NONE	2.000000	2.045959	MACS1720.3+3536	archived	Nov 27 2005 3:12AM	N	Allen
05	800554	6106	ACIS-I	NONE	40.000000	35.770890	MACS0159.8-0849	archived	Dec 4 2004 12:14PM	N	Allen
05	800553	6105	ACIS-I	NONE	40.000000	37.770350	MACS0011.7-1523	archived	Jun 28 2005 11:51AM	N	Allen
05	800552	6104	ACIS-I	NONE	10.000000	9.737000	Abell2204	archived	Sep 20 2004 11:42AM	N	Allen
05	800551	6103	ACIS-I	NONE	10.000000	10.406000	PKS0745-191	archived	Sep 24 2004 12:35AM	N	Allen
05	800550	6102	ACIS-I	NONE	10.000000	10.127000	Abell478	archived	Sep 13 2004 5:15PM	N	Allen
05	800549	6101	ACIS-I	NONE	10.000000	10.050190	Abell2029	archived	Dec 17 2004 3:50AM	N	Allen
05	701014	5302	ACIS-S	NONE	30.000000	31.121000	NGC4395	archived	Apr 11 2004 1:28AM	N	Moran
05	701013	5301	ACIS-S	NONE	30.000000	29.730000	NGC4395	archived	Apr 10 2004 3:06AM	N	Moran
05	600412	5360	ACIS-I	NONE	5.000000	5.174000	CXOGCJ174540.0-2900	archived	Aug 28 2004 12:21PM	N	Baganoff
05	500600	6260	ACIS-S	NONE	10.000000	10.140790	GCRTJ1745-3009	archived	May 1 2005 12:47AM	D	Hyman
05	500591	6129	ACIS-I	NONE	20.000000	19.508000	GRB040912	archived	Sep 21 2004 11:18AM	N	Ricker
05	500590	6128	ACIS-I	NONE	20.000000	18.168000	GRB040912	archived	Sep 15 2004 10:24PM	N	Ricker
05	500585	6098	ACIS-I	NONE	5.000000	4.707000	VHEJ1303-63	archived	Sep 25 2004 6:02PM	D	Halpern
05	500508	5365	ACIS-S	NONE	10.000000	10.163000	GRB040812	archived	Aug 22 2004 10:12AM	N	Kouveliotou
05	500507	5364	ACIS-S	NONE	10.000000	10.175000	GRB040812	archived	Aug 17 2004 7:28AM	N	Kouveliotou
05	500506	5314	ACIS-S	NONE	30.000000	30.156000	GRB031203	archived	Apr 18 2004 11:59AM	D	Kouveliotou
05	500505	5306	ACIS-S	NONE	15.000000	14.758000	SN2001em	archived	Apr 4 2004 7:41PM	N	Pooley
05	500504	5305	HRC-S	LETG	35.000000	35.705000	RXJ0720-3125	archived	Feb 27 2004 4:53AM	N	Vink
05	500503	5298	ACIS-S	NONE	25.000000	21.848000	GRB031203	archived	Jan 22 2004 9:34PM	N	Kulkarni
05	400376	5291	ACIS-S	NONE	10.000000	10.137000	PSRJ0737-3039	archived	Jan 18 2004 7:56PM	1	McLaughlin
05	300145	5293	HRC-S	LETG	40.000000	41.953000	MiraAB	archived	Jan 11 2004 2:09PM	D	Karovska
05	300144	5292	HRC-S	LETG	10.000000	10.308000	V4743Sgr	archived	Feb 28 2004 1:31AM	N	Starrfield
05	200298	5308	ACIS-S	NONE	5.000000	4.963000	IRAS05436-0007	archived	Mar 22 2004 12:35AM	N	Kastner
05	200297	5307	ACIS-S	NONE	5.000000	5.561000	IRAS05436-0007	archived	Mar 7 2004 1:41AM	N	Kastner
05	100053	5321	ACIS-S	NONE	3.400000	3.558000	C/2001Q4(NEAT)	archived	May 12 2004 6:50PM	D	Lisse
05	100053	5325	ACIS-S	NONE	3.300000	3.484000	C/2001Q4(NEAT)	archived	May 12 2004 7:55PM	D	Lisse
05	100053	5326	ACIS-S	NONE	3.300000	3.471000	C/2001Q4(NEAT)	archived	May 12 2004 8:58PM	D	Lisse
04	800375	4438	ACIS-S	NONE	30.000000	29.136000	RCS0439.6-2905	archived	Jun 6 2003 6:17AM	D	Bautz
04	500500	5247	HRC-I	NONE	5.000000	4.871000	IGRJ16316-4028	archived	Jan 18 2004 1:07PM	D	Foschini
04	500499	5246	ACIS-S	NONE	25.000000	25.509000	SN2003jd	archived	Nov 10 2003 7:08PM	N	Watson
04	500498	5240	HRC-I	NONE	3.000000	2.884000	XTEJ1810-197	archived	Nov 1 2003 3:26PM	N	Israel
04	500415	4454	HRC-I	NONE	3.000000	2.833000	XTEJ1810-197	archived	Aug 27 2003 10:43PM	N	Gotthelf
04	500413	4449	ACIS-S	NONE	20.000000	18.435000	SN2002ic	archived	Aug 11 2003 9:40PM	D	Hughes
04	500412	4443	ACIS-S	NONE	25.000000	25.125000	SGR1806-20	archived	Aug 3 2003 12:13PM	D	Woods
04	500411	4432	ACIS-S	LETG	100.000000	98.100000	H2650	archived	Mar 29 2003 3:05AM	N	Ricker
04	500410	4425	ACIS-S	NONE	40.000000	40.172000	GRB030226	archived	Feb 27 2003 5:14PM	N	Pedersen
04	500409	4417	ACIS-S	NONE	30.000000	30.415000	SN2003L	archived	Feb 10 2003 3:59AM	N	Kulkarni
04	400324	4439	ACIS-S	HETG	10.000000	9.987000	XTEJ1814-338	archived	Jun 20 2003 2:12AM	D	Chakrabarty
04	400323	4434	ACIS-S	NONE	47.000000	47.051000	IGRJ16358-4726	archived	Apr 21 2003 3:49AM	D	Kouveliotou
04	400322	4426	HRC-S	NONE	3.000000	2.824000	XTEJ1807-294	archived	Mar 10 2003 8:34AM	D	MARKWARDT
04	400321	4424	ACIS-S	NONE	10.000000	10.687000	XTEJ1908+094	archived	May 14 2003 1:51AM	D	Jonker
04	400320	4423	ACIS-S	NONE	5.000000	5.150000	XTEJ1908+094	archived	Apr 19 2003 3:14PM	D	Jonker
04	400319	4422	ACIS-S	NONE	5.000000	5.212000	XTEJ1908+094	archived	Mar 24 2003 12:07AM	D	Jonker
04	400318	4420	ACIS-S	HETG	75.000000	76.220000	GX339-4	archived	Mar 17 2003 8:05PM	D	Miller
04	100052	5311	HRC-I	NONE	5.640000	5.521000	Moon	archived	May 4 2004 4:36AM	N	Drake
04	100052	5312	HRC-I	NONE	5.600000	5.679000	Moon	archived	Jun 2 2004 8:41AM	N	Drake
04	100052	5324	HRC-I	NONE	5.640000	5.772000	Moon	archived	May 4 2004 7:00AM	N	Drake
04	100052	5327	HRC-I	NONE	5.600000	5.638000	Moon	archived	Jun 2 2004 10:58AM	N	Drake
04	100052	5351	HRC-I	NONE	5.600000	5.471000	Moon	archived	Jul 27 2004 11:13PM	N	Drake
04	100052	5352	HRC-I	NONE	4.700000	4.657000	Moon	archived	Jul 28 2004 1:30AM	N	Drake
03	400247	3476	ACIS-S	NONE	5.000000	0.000000	RXJ170930.2-263927	discarded	Apr 21 2002 5:16AM	D	Jonker
03	700612	3419	ACIS-S	NONE	100.000000	97.944000	MGJ0414+0534	archived	Jan 9 2002 12:00AM	D	Chartas
03	600330	4360	ACIS-I	NONE	5.000000	4.969000	M31	archived	Aug 11 2002 6:15PM	N	Primini
03	500408	4409	ACIS-S	NONE	30.000000	30.431000	GRB021004	archived	Nov 25 2002 5:51PM	N	Sako
03	500407	4405	ACIS-S	NONE	10.000000	10.115000	SN2002HI	archived	Dec 10 2002 5:45PM	N	Lewin
03	500406	4404	ACIS-S	NONE	30.000000	30.335000	SN2002HH	archived	Nov 25 2002 8:58AM	N	Lewin
03	500405	4381	ACIS-S	HETG	80.000000	88.130000	GRB021004	archived	Oct 5 2002 8:58AM	N	HARRISON
03	500404	4364	ACIS-S	HETG	80.000000	78.122000	GRB020813	archived	Aug 13 2002 11:46PM	N	Ricker
03	500298	3496	ACIS-S	NONE	25.000000	24.188000	SN2001IG	archived	Jun 11 2002 6:20AM	N	Schlegel
03	500297	3495	ACIS-S	NONE	25.000000	23.734000	SN2001IG	archived	May 21 2002 11:53PM	N	Schlegel
03	500296	3494	ACIS-S	NONE	15.000000	14.755000	XRF020427	archived	May 14 2002 3:55AM	N	Fox
03	500295	3493	ACIS-S	NONE	15.000000	13.916000	XRF020427	archived	May 6 2002 5:46AM	N	Fox
03	500294	3477	ACIS-S	NONE	20.000000	20.057000	GRB020321	archived	Mar 31 2002 2:13AM	N	Fox
03	500292	3449	ACIS-S	NONE	3.000000	2.662000	SGR1900+14	archived	Mar 11 2002 11:03AM	D	Woods
03	500291	3441	ACIS-I	NONE	15.000000	14.672000	XRF011130	archived	Feb 20 2002 10:18AM	N	Ricker
03	500287	3437	ACIS-I	NONE	10.000000	10.064000	GRB020127	archived	Feb 11 2002 11:17AM	N	Fox
03	500286	3436	ACIS-I	NONE	10.000000	9.968000	GRB020127	archived	Jan 31 2002 10:37PM	N	Fox
03	400316	4358	ACIS-I	NONE	5.000000	4.979000	TEVJ2032+4130	archived	Aug 11 2002 8:07PM	D	Butt
03	400315	4285	ACIS-S	NONE	5.000000	4.687000	V4641SGR	archived	Aug 5 2002 4:16AM	D	RUPEN
03	400270	3724	ACIS-S	HETG	30.000000	26.400000	CYGX-1	archived	Jul 30 2002 5:42PM	N	Feng
03	400268	3672	ACIS-S	NONE	20.000000	18.255000	XTEJ1550-564	archived	Jun 19 2002 9:17AM	D	CORBEL
03	400267	3671	ACIS-S	NONE	5.000000	5.538000	1E1740.7-2942	archived	Aug 17 2002 1:24PM	D	Heindl
03	400266	3670	ACIS-S	HETG	10.000000	10.140000	1E1740.7-2942	archived	Jun 13 2002 7:29PM	D	Heindl
03	400265	3661	ACIS-S	LETG	20.000000	17.961000	XTEJ0929-314	archived	May 15 2002 12:43AM	D	Chakrabarty
03	400256	3490	ACIS-S	NONE	7.000000	7.648000	AQLX-1	archived	Sep 3 2002 4:27PM	D	Rutledge
03	400255	3489	ACIS-S	NONE	7.000000	7.858000	AQLX-1	archived	Aug 18 2002 8:19AM	D	Rutledge
03	400254	3488	ACIS-S	NONE	7.000000	7.172000	AQLX-1	archived	Jul 22 2002 9:01PM	D	Rutledge
03	400253	3487	ACIS-S	NONE	7.000000	6.549000	AQLX-1	archived	Jul 5 2002 3:45PM	D	Rutledge
03	400252	3486	ACIS-S	NONE	7.000000	7.151000	AQLX-1	archived	Jun 11 2002 3:50AM	D	Rutledge
03	400251	3485	ACIS-S	NONE	7.000000	7.672000	AQLX-1	archived	May 20 2002 7:41AM	D	Rutledge
03	400250	3484	ACIS-S	NONE	7.000000	7.160000	AQLX-1	archived	May 4 2002 11:04PM	D	Rutledge
03	400249	3483	HRC-S	NONE	3.000000	2.976000	XTEJ1751-305	archived	Apr 10 2002 4:31PM	D	MARKWARDT
03	400248	3481	ACIS-S	NONE	1.000000	1.133000	XTEJ1908+094	archived	Apr 15 2002 5:39AM	N	RUPEN
03	400247	3492	ACIS-S	NONE	5.000000	5.231000	RXJ170930.2-263927	archived	Apr 23 2002 9:58PM	D	Jonker
03	400246	3475	ACIS-S	NONE	5.000000	5.965000	RXJ170930.2-263927	archived	Apr 10 2002 5:49PM	D	Jonker
03	400239	3464	ACIS-S	NONE	5.000000	5.147000	RXJ170930.2-263927	archived	Apr 1 2002 12:43AM	D	Jonker
03	400238	3463	ACIS-S	NONE	8.477000	8.477000	RXJ170930.2-263927	archived	Mar 18 2002 11:46AM	D	Jonker
03	400237	3462	ACIS-S	NONE	15.000000	14.210000	RXJ170930.2-263927	archived	Mar 12 2002 1:52PM	D	Jonker
03	400236	3448	ACIS-S	NONE	30.000000	27.457000	XTEJ1550-564	archived	Mar 11 2002 3:16PM	D	CORBEL
03	300090	3455	ACIS-S	HETG	35.000000	34.457000	GKPER	archived	Apr 9 2002 3:06PM	D	Mauche
03	300089	3454	ACIS-S	HETG	35.000000	32.102000	GKPER	archived	Mar 27 2002 9:49AM	D	Mauche
03	300087	3434	ACIS-S	NONE	5.000000	5.629000	IMNORMAE	archived	Feb 4 2002 6:01PM	N	Starrfield
03	100038	4410	HRC-I	NONE	1.000000	1.116000	EARTH	archived	Feb 7 2003 1:23AM	D	Gladstone
03	100034	3447	ACIS-S	NONE	12.000000	11.718000	C/2002C1	archived	Apr 15 2002 1:52AM	D	Dennerl
03	100034	3453	ACIS-S	NONE	12.000000	11.964000	C/2002C1	archived	Apr 15 2002 11:15PM	D	Dennerl
03	100032	3412	ACIS-S	NONE	20.000000	20.122000	FXRT011030	archived	Nov 29 2001 11:09AM	D	HARRISON
03	100031	3411	ACIS-S	NONE	50.000000	47.209000	FXRT011030	archived	Nov 9 2001 5:44PM	N	HARRISON
02	900066	2239	ACIS-I	NONE	132.000000	132.469000	CDFS	archived	Dec 23 2000 5:49PM	N	GIACCONI
02	900066	2312	ACIS-I	NONE	136.000000	125.323000	CDFS	archived	Dec 13 2000 3:47AM	N	GIACCONI
02	900066	2313	ACIS-I	NONE	132.000000	132.115000	CDFS	archived	Dec 21 2000 2:28AM	N	GIACCONI
02	900066	2406	ACIS-I	NONE	31.000000	30.079000	CDFS	archived	Dec 10 2000 11:51PM	N	GIACCONI
02	900066	2409	ACIS-I	NONE	69.000000	69.895000	CDFS	archived	Dec 19 2000 4:12AM	N	GIACCONI
02	800178	2427	ACIS-S	NONE	20.000000	18.094000	PKS0745-191	archived	Jun 16 2001 5:50AM	D	Fabian
02	700608	3395	ACIS-S	NONE	30.000000	28.777000	MGJ0414+0534	archived	Nov 9 2001 8:34AM	D	Chartas
02	700607	3359	ACIS-S	NONE	6.000000	5.760000	SDSSPJ083643+005453	archived	Jan 29 2002 12:02PM	N	Brandt
02	700606	3358	ACIS-S	NONE	8.000000	8.262000	SDSSPJ130608+035626	archived	Jan 29 2002 6:28AM	N	Brandt
02	700605	3357	ACIS-S	NONE	8.000000	8.057000	SDSSPJ103027+052455	archived	Jan 29 2002 9:11AM	N	Brandt
02	700393	2454	ACIS-S	NONE	5.000000	4.500000	CIRCINUSGALAXY	archived	May 2 2001 4:20PM	N	Matt
02	500285	3380	HRC-S	LETG	170.000000	167.446000	RXJ1856.5-3754	archived	Oct 10 2001 5:18AM	N	Tananbaum
02	500285	3381	HRC-S	LETG	170.000000	171.073000	RXJ1856.5-3754	archived	Oct 12 2001 7:31PM	N	Tananbaum
02	500285	3382	HRC-S	LETG	100.500000	101.926000	RXJ1856.5-3754	archived	Oct 8 2001 8:31AM	N	Tananbaum
02	500285	3399	HRC-S	LETG	9.500000	9.318000	RXJ1856.5-3754	archived	Oct 15 2001 11:59AM	N	Tananbaum
02	500200	2459	ACIS-S	NONE	20.000000	18.896000	SGR1900+14	archived	Apr 30 2001 11:27PM	N	Kouveliotou
02	500199	2458	ACIS-S	NONE	20.000000	20.835000	SGR1900+14	archived	Apr 22 2001 4:58AM	N	Kulkarni
02	500197	2424	ACIS-S	NONE	30.000000	29.923000	GRB010222	archived	Feb 22 2001 10:28PM	D	Piro
02	400234	3407	ACIS-S	HETG	30.000000	30.000000	CYGX-1	archived	Oct 28 2001 4:33PM	D	Cui
02	400233	3360	ACIS-S	NONE	2.500000	2.641000	NGC6440	archived	Aug 18 2001 8:23PM	N	in'tZand
02	400164	2430	HRC-I	NONE	10.000000	9.889000	GRS1758-258	archived	Mar 24 2001 7:43AM	D	Heindl
02	400163	2429	ACIS-S	HETG	30.000000	30.280000	GRS1758-258	archived	Mar 24 2001 10:58AM	D	Heindl
02	400162	2428	ACIS-S	NONE	20.000000	20.400000	KS1731-260	archived	Mar 27 2001 12:34AM	D	Wijnands
02	400161	2415	ACIS-S	HETG	30.000000	30.146000	CYGNUSX-1	archived	Jan 4 2001 6:20AM	D	Miller
02	300067	2514	ACIS-S	NONE	10.000000	10.179000	WZSGE	archived	Sep 19 2001 1:56AM	N	Kuulkers
02	300066	2513	ACIS-S	NONE	10.000000	12.075000	WZSGE	archived	Aug 22 2001 8:41AM	N	Kuulkers
02	300065	2512	ACIS-S	NONE	5.000000	4.910000	WZSGE	archived	Aug 7 2001 5:47PM	N	Kuulkers
02	300061	2508	ACIS-S	NONE	5.000000	5.159000	WZSGE	archived	Jul 29 2001 4:49PM	N	Wheatley
02	300059	2506	HRC-S	LETG	20.000000	19.984000	WZSGE	archived	Aug 18 2001 8:07AM	N	Wheatley
02	300058	2505	HRC-S	LETG	20.000000	18.760000	WZSGE	archived	Aug 6 2001 7:53PM	N	Wheatley
02	300057	2504	HRC-S	LETG	20.000000	19.950000	WZSGE	archived	Jul 27 2001 2:44AM	N	Wheatley
02	300056	2492	ACIS-S	NONE	20.000000	19.885000	CIAQL	archived	Aug 1 2001 12:52PM	D	Greiner
02	300054	2465	ACIS-S	NONE	2.000000	2.149000	CIAQL	archived	Jun 1 2001 8:41PM	D	Greiner
02	200125	2338	ACIS-S	HETG	25.000000	24.838000	WR140	archived	May 8 2001 8:01PM	D	Pollock
02	200124	2337	ACIS-S	HETG	50.000000	46.124000	WR140	archived	Dec 29 2000 10:32AM	D	Pollock
01	100011	961	HRC-S	LETG	19.100000	0.000000	Discarded	discarded	Nov 26 1999 9:02AM	3	WAITE
01	700266	1715	HRC-S	LETG	20.000000	19.839000	MRK421	archived	May 29 2000 5:53PM	N	FRUSCIONE
01	700265	1714	ACIS-S	HETG	20.000000	19.830000	MRK421	archived	May 29 2000 11:57AM	N	FRUSCIONE
01	700202	442	ACIS-S	NONE	5.000000	4.976000	NGC526A	archived	Apr 23 2000 6:54AM	S	Wilson
01	570470	1520	ACIS-S	NONE	25.000000	24.035000	NGC3184	archived	Feb 3 2000 11:00AM	3	Schlegel
01	500093	364	HRC-I	NONE	50.000000	48.159000	PSRB0833-45	archived	Feb 21 2000 2:11AM	N	Helfand
01	500092	1518	HRC-I	NONE	50.000000	50.215008	PSRB0833-45	archived	Jan 20 2000 12:33AM	N	Helfand
01	400112	1846	ACIS-S	NONE	5.000000	4.630000	XTEJ1550-564	archived	Sep 11 2000 5:10AM	D	Tomsick
01	400111	1845	ACIS-S	NONE	5.000000	5.164000	XTEJ1550-564	archived	Aug 21 2000 9:08AM	D	Tomsick
01	400110	1701	ACIS-S	LETG	30.000000	27.830000	XTEJ1118+48	archived	Apr 18 2000 6:36PM	D	McClintock
01	400093	426	ACIS-S	HETG	20.000000	18.318000	CYGX-3	archived	Apr 6 2000 8:17PM	N	McCollough
01	400092	425	ACIS-S	HETG	20.000000	21.533000	CYGX-3	archived	Apr 4 2000 2:05PM	N	McCollough
01	300053	2336	ACIS-S	HETG	20.000000	19.222000	ZANDROMEDAE	archived	Nov 13 2000 3:19PM	D	Charles
01	300041	1706	ACIS-S	HETG	60.000000	59.881000	EXHYA	archived	May 18 2000 9:59AM	D	Howell
01	300037	327	ACIS-S	NONE	5.000000	4.947000	Mispointing	archived	Feb 8 2000 4:18PM	D	DiStefano
01	100011	1464	HRC-S	LETG	14.760000	14.778000	JUPITER	archived	Nov 26 1999 2:35PM	3	WAITE
01	100011	1465	HRC-S	LETG	23.150000	23.418000	JUPITER	archived	Nov 26 1999 8:07PM	3	WAITE
01	100010	960	ACIS-S	NONE	22.600000	22.380800	JUPITER	archived	Nov 25 1999 7:38PM	3	WAITE
01	100010	1463	ACIS-S	NONE	22.600000	22.364800	JUPITER	archived	Nov 26 1999 2:10AM	3	WAITE

---

Canceled DDT Observations

Cycle	Sequence Number	ObsID	Instrument	Grating	Approved Exposure Time	Target	Status	PI Name
08	900737	9576	ACIS-I	NONE	2.000000	ChandraDeepField-S	canceled	Tananbaum
08	900737	9577	ACIS-I	NONE	30.000000	ChandraDeepField-S	canceled	Tananbaum
07	300182	7301	ACIS-S	HETG	15.000000	RSOph	canceled	Starrfield
07	300181	7300	ACIS-S	HETG	15.000000	RSOph	canceled	Starrfield
07	300180	7299	HRC-S	LETG	20.000000	RSOph	canceled	Starrfield
07	200461	8475	ACIS-I	NONE	10.000000	L1415EXor	canceled	Kastner
06	200365	6206	ACIS-S	NONE	8.333333	V1118Ori	canceled	Audard
06	200364	6205	ACIS-S	NONE	8.333333	V1118Ori	canceled	Audard
04	500414	4450	ACIS-S	NONE	20.000000	SN2002ic	canceled	Hughes
04	100052	5328	HRC-I	NONE	2.500000	Moon	canceled	Drake
04	100052	5313	HRC-I	NONE	4.700000	Moon	canceled	Drake
03	700614	3421	ACIS-S	NONE	30.000000	MGJ0414+0534	canceled	Chartas
03	700613	3420	ACIS-S	NONE	30.000000	MGJ0414+0534	canceled	Chartas
03	500299	3497	ACIS-S	NONE	25.000000	SN2001IG	canceled	Schlegel
03	500290	3440	ACIS-S	NONE	25.000000	SN2002AP	canceled	Schlegel
03	500289	3439	ACIS-S	NONE	25.000000	SN2002AP	canceled	Schlegel
03	500288	3438	ACIS-S	NONE	25.000000	SN2002AP	canceled	Schlegel
03	400269	3723	ACIS-S	NONE	30.000000	MACHO-99-BLG-22	canceled	Reynolds
03	400245	3470	ACIS-S	NONE	10.000000	RXJ170930.2-263927	canceled	Jonker
03	400244	3469	ACIS-S	NONE	10.000000	RXJ170930.2-263927	canceled	Jonker
03	400243	3468	ACIS-S	NONE	10.000000	RXJ170930.2-263927	canceled	Jonker
03	400242	3467	ACIS-S	NONE	5.000000	RXJ170930.2-263927	canceled	Jonker
03	400241	3466	ACIS-S	NONE	5.000000	RXJ170930.2-263927	canceled	Jonker
03	400240	3465	ACIS-S	NONE	5.000000	RXJ170930.2-263927	canceled	Jonker
03	300088	3435	ACIS-S	NONE	25.000000	IMNORMAE	canceled	Starrfield
03	100033	3446	ACIS-S	NONE	8.000000	C/2002C1	canceled	Dennerl
02	700611	3398	ACIS-S	NONE	30.000000	MGJ0414+0534	canceled	Chartas
02	700610	3397	ACIS-S	NONE	30.000000	MGJ0414+0534	canceled	Chartas
02	700609	3396	ACIS-S	NONE	30.000000	MGJ0414+0534	canceled	Chartas
02	500202	2461	ACIS-S	NONE	5.000000	SGR1900+14	canceled	Kouveliotou
02	500201	2460	ACIS-S	NONE	5.000000	SGR1900+14	canceled	Kouveliotou
02	500198	2457	ACIS-S	NONE	0.000000	SGR1900+14	canceled	Kulkarni
02	300064	2511	ACIS-S	NONE	10.000000	WZSGE	canceled	Wheatley
02	300063	2510	ACIS-S	NONE	10.000000	WZSGE	canceled	Wheatley
02	300062	2509	ACIS-S	NONE	10.000000	WZSGE	canceled	Wheatley
02	300055	2466	ACIS-S	NONE	0.000000	CIAQL	canceled	Greiner
01	400113	1847	ACIS-S	NONE	5.000000	XTEJ1550-564	canceled	Tomsick
01	100027	2517	ACIS-S	NONE	9.000000	COMET19P/BORRELLY	canceled	Dennerl
01	100027	3377	ACIS-S	NONE	9.000000	COMET19P/BORRELLY	canceled	Dennerl
01	100027	3378	ACIS-S	NONE	9.000000	COMET19P/BORRELLY	canceled	Dennerl
01	100027	3379	ACIS-S	NONE	9.000000	COMET19P/BORRELLY	canceled	Dennerl

Sequence Number: 200656

Title : X-ray Emission from V838 Mon: Stellar Merger or Ejecta-Companion
Interactions?
PI: Kastner
Abstract: The nature of the infamous 2002 outburst of V838 Mon (Bond 2007;
Tylenda et al. 2009 [T09]) remains uncertain. No nova-like "hot phase"
was observed and the presence of a B3V companion and a small cluster
implies the system is too young to harbor an accreting white dwarf.
Among the leading models for the outburst is that of a stellar merger
(Soker & Tylenda 2007 [ST07]). The merger product should become
magnetically active well after outburst (ST07), suggesting that V838
Mon should make a delayed appearance as an X-ray source. Indeed, V838
Mon went undetected by CXO in 2003 (Orio et al 2003), but when we
reobserved the object in 2008 with XMM we detected a luminous X-ray
source very near its position (Antonini et al 2009). This source may be
the spun-up merger remnant. However, V838Mon s ejecta had just engulfed
its companion at the time of our XMM observation (T09). Hence the XMM
source might be due instead to interactions between V838 Mon s ejecta
and its companion.

Sequence Number: 701973

Title : The nature of the highly-variable X-ray galaxy KUG 1259+280
PI: Watson
Abstract: We have discovered a bright, strongly variable 2XMM X-ray source which
is <2" from the nucleus of a nearby (D~100 Mpc) post-starburst galaxy
KUG 1259+280. In the XMM-Newton discovery observation the source shows
a strong flare lasting 2500 sec with a factor ~8 flux increase on a
timescale <1000 sec. Even more remarkably the X-ray spectrum is
characterized by an unprecedently soft continuum well-fit with a
power-law model with gamma=4.7. The short-timescale variability,
luminosity (Lx~3E41 erg/sec) and location close to the nucleus suggests
an NLS1 AGN, but only weak, narrow Balmer lines (consistent with
starburst) are detected in the SDSS spectrum once host galaxy
contamination is removed. Proposed Chandra observation will locate the
X-ray source to ~0.2 arcsec (~100 pc) to see if it is truly coincident
with the nucleus - importantly if it is off-nucleus this would make it
an ULX. Observation will also check for faint extended X-ray emission
and constrain variability/spectrum.

Sequence Number: 501174

Title : Searching for the X-ray counterpart to J1622-49
PI: Rea
Abstract: A new neutron star has been recently discovered during the Parkes High
Time Resolution Universe Survey. Its radio emission is highly variable
reaching strong luminosities (up to ~35mJy). We ask for a 20ks Chandra
ACIS-I observation to characterize its X-ray counterpart, in search for
a similarly variable X-ray emission.

Sequence Number: 401125

Title : A precise position for the intermediate mass black hole candidate in
ESO 243-49
PI: Farrell
Abstract: We recently identified a ULX that provides the strongest evidence for
the existence of intermediate mass black holes (Farrell et al., 2009,
Nature, 460, 73). Previous observations with XMM and Swift gave
incompatible positions at the 1 sigma level. We obtained a 1 ks Chandra
DDT observation on 07/04/09 to resolve this discrepancy. The ULX was
not detected, so has dropped by a factor >6 in flux. By analogy with
stellar mass black holes, this might indicate a transition into a
low/hard state; such a transition has never been observed so far from
any ULX. Triggered by this result and the unique properties of the
source, we are currently preparing requests for deep ground and
space-based telescope observations, whose analysis will require a high
precision that only Chandra can provide. Even a non-detection would be
a highly significant result, as it could indicate the ULX has undergone
a transition into the low/hard state; a phenomenon commonly observed in
Galactic X-ray binaries.

Sequence Number: 401124

Title : Following the Decay of NGC 6440 X-2
PI: Heinke
Abstract: On July 28-29, our GO Chandra image of NGC 6440 discovered a 2nd
transient LMXB in outburst in the globular cluster NGC 6440 (Atel
2139). RXTE/PCA saw indications of flaring at 0.7 Hz, similar to 1 Hz
flaring from SAX J1808, which indicated propeller instabilities in the
flow (Patruno+09). We request one 5-ksec ACIS-S observation of NGC 6440
by August 14 to determine whether this transient has returned to full
quiescence (<1e31) or undergoes accretion instabilities at low
(Lx~5e32) levels, as SAX J1808 did (Campana+08). 5 ksec will give >10
cts for Lx(0.5-10)>3e32 ergs/s (either BB @0.2 keV, or PL @index~2.2 as
seen by Swift for 6440 X-2).

Sequence Number: 401066

Title : A precise position for the intermediate mass black hole candidate in
ESO 243-49
PI: Farrell
Abstract: While investigating the 2XMM catalogue, we identified a new ULX in the
galaxy ESO 243-49 with an unabsorbed 0.2-10 keV Lx = 1.1E42 erg/s. A
follow-up DDT observation with XMM found the spectrum had changed
significantly, ruling out multiple low-luminosity sources. The Lx is
almost an order of magnitude greater than the previous record holder,
which when taken with the steep power-law spectrum and lack of radio
emission rules out beaming. This ULX, with a conservative mass lower
limit of ~500 Msun, provides the strongest evidence for the existence
of intermediate mass black holes (Farrell et al., 2009, Nature, in
press). This object is unique, puzzling and worth following-up given
the significance of the results. We will begin monitoring this ULX with
Swift in August to search for variability. Any significant changes in
flux/spectrum will trigger requests for deep observations with ground
based telescopes. Before such observations can take place a high
precision position is required.

Sequence Number: 401065

Title : Simultaneous Chandra/ATCA observation of GRO J1655-40 in quiescence
PI: Gallo
Abstract: We have recently been awarded a very deep (12 hr) radio observation of
the quiescent X-ray binary GRO J1655-40 with the newly refurbished
Australia Telescope Compact Array (ATCA) on June 7. The goal of this
observation is to probe jet formation at the lowest possible mass
accretion rates. Beside A0620-00, which was observed simultaneously by
the VLA and Chandra in 2005 (Gallo et al. 2006, MNRAS, 370, 1351),
there is only one other quiescent black-hole system whose properties
enable us to probe jet formation at such low accretion rates, and that
is GRO J1655-40. As well as anchoring the radio:X-ray correlation at
the lowest luminosities, we should be also able to detect the radio
spectrum of a truly quiescent source for the first time. In turn, this
will allow us to compare the broadband spectral energy distribution of
a quiescent stellar mass black hole to that of the quiescent 4E+6 solar
mass black hole in the Galactic Center.

Sequence Number: 701771

Title : Chandra observation of a flaring galaxy with strong optical
emission-line light echo
PI: Komossa
Abstract: We have discovered among SDSS-DR6, in Dec. 2007, a galaxy which is
unique in showing super-strong high-ionization iron lines and very
unusual double-peaked Balmer lines which are fading away, but have not
yet disappeared. The high degree of line ionization implies that we see
the light-echo of an (unobserved) EUV-X-ray flare. We have confirmed,
with optical ToO photometry on Jan. 1, 2008 the low-energy tail of this
flare in the optical and NIR. Only a few X-ray flaring galaxies are
known. This is the first time we have seen such a broad line and
continuum response. With Chandra, we will for the first time detect the
actual X-rays from this flare, characterize the X-ray emission, locate
the flare within 1 kpc of the nucleus, and test the favored scenario -
tidal disruption of a star - before the flare has faded away. Depending
on the measured source's X-ray brightness, we will then consider X-ray
monitoring to map the emission-line changes in response to the X-ray
fading.

Sequence Number: 501152

Title : The X-ray light-curve of GRB 080307
PI: Page
Abstract: The canonical X-ray light-curve with a steep-plateau-normal decay, has
been attributed to continued energy injection; when this input ceases,
we see the steepening to the standard decay (alpha~1.3). In the case of
GRB 080307, the onset of the plateau was unusually late and, uniquely,
the decay was still continuing with a slope of <1 more than a month
after the burst. If intrinsic, this slow decay would place severe
constraints on the proposed injection model, requiring the engine to be
active for a very long time. Deep Gemini imaging reveals a second
optical source within the XRT error circle, which is a possible source
of contamination. Chandra's PSF and sensitivity will allow us to test
whether there is any contamination from this nearby source and whether
the decay has broken.

Sequence Number: 501018

Title : An Unexpected Re-Brightening in SHB 080503: Afterglow or
mini-Supernova, 2nd Epoch
PI: Butler
Abstract: Gaining a deep understanding of the origin and nature of Short
(duration) Hard (spectrum) Gamma-ray Bursts (SHBs) is one of the last
frontiers of GRB research. We can now say almost for certain that the
progenitors of SHBs are different from those of Long-Soft GRBs (LSBs).
This is based almost entirely on observations of the host galaxies of
SHBs, which seem to be an older population than the hosts of LSBs:
whereas the 50+ hosts of LSBs appear to be underluminous star bursts,
and a handful of the bursts themselves have been directly associated
with supernova (SN) explosions. SHB hosts span the range from giant
elliptical to faint blue galaxies. A multi-wavelength campaign is
critical to ameliorate the large theoretical uncertainty as to what
types of progenitor systems --- a possible ``mini-SN'' (Li \& Paczynski
1998) from a compact object mergers or binary WD merger (Levan et al.
2006) --- are at the origin of SHBs.

Sequence Number: 501017

Title : An Unexpected Re-Brightening in SHB 080503: Afterglow or
mini-Supernova
PI: Butler
Abstract: Gaining a deep understanding of the origin and nature of Short
(duration) Hard (spectrum) Gamma-ray Bursts (SHBs) is one of the last
frontiers of GRB research. We can now say almost for certain that the
progenitors of SHBs are different from those of Long-Soft GRBs (LSBs).
This is based almost entirely on observations of the host galaxies of
SHBs, which seem to be an older population than the hosts of LSBs:
whereas the 50+ hosts of LSBs appear to be underluminous star bursts,
and a handful of the bursts themselves have been directly associated
with supernova (SN) explosions. SHB hosts span the range from giant
elliptical to faint blue galaxies. A multi-wavelength campaign is
critical to ameliorate the large theoretical uncertainty as to what
types of progenitor systems --- a possible ``mini-SN'' (Li \& Paczynski
1998) from a compact object mergers or binary WD merger (Levan et al.
2006) --- are at the origin of SHBs.

Sequence Number: 501014

Title : Chandra observations of a nearby supernova
PI: Roelofs
Abstract: We propose Chandra observations of the nearby type-Ia supernova
SN2007on to characterize its X-ray emission, which will help us
constrain the nature of the progenitor. We ask for an initial 40ks
which will enable us to put useful constraints on its X-ray flux.

Sequence Number: 501014

Title : Chandra observations of a nearby supernova
PI: Roelofs
Abstract: We propose Chandra observations of the nearby type-Ia supernova
SN2007on to characterize its X-ray emission, which will help us
constrain the nature of the progenitor. We ask for an initial 40ks
which will enable us to put useful constraints on its X-ray flux.

Sequence Number: 401051

Title : Is XTE J1701-407 Extended?
PI: Kaplan
Abstract: We recently observed the neutron star X-ray transient XTE J1701-407
with Chandra, using 1 ks of ACIS-S data for localization. However, the
Chandra data do not show a point source. Instead the source appears
extended over ~6 arcsec. We have investigated the data, consulting with
experts both at MIT and SAO, and cannot ascribe the data to purely
instrumental effects (aspect errors or pileup). The extended X-ray
emission could come from an outflow or a dust scattering halo - both
very interesting and rare phenomena. Jets allow detailed calorimetry of
the outbursts, while scattering halos lead to geometric distances. We
request a 5 ks ACIS-S subarray observation to definitively assess the
morphology, trying to discriminate between these scenarios before the
target fades into quiescence.

Sequence Number: 401050

Title : V Puppis: A black hole triple?
PI: Maccarone
Abstract: The nearby eclipsing binary VPup has recently been suggested on the
basis of eclipse timing residuals to have a third body with a ~5 year
orbital period and a mass of ~10 solar masses, but for which there is
no spectroscopic evidence, making it the only strong candidate for
having a black hole in a wide binary in the Galaxy. At a distance of
300 pc, this object can be studied in great detail, even if it is
extremely faint, and is the only black hole candidate with a Hipparcos
parallax distance. Past observatories showed variable X-ray emission
from this region at a level which was reasonable for Bondi accretion
from the stellar wind of the B giant in the VPup. We have recently made
ATCA observations of this region and need X-ray observations as well,
to compare the two fluxes or upper limits to determine whether it is
reasonable for such a flux ratio to come from a stellar mass black
hole, and to ensure that the past X-ray emission really is from VPup,
rather than a nearby object.

Sequence Number: 400934

Title : Locating the Ultraluminous Supersoft X-ray Source in NGC300
PI: Kong
Abstract: We propose to obtain the first Chandra image of the nearest very
luminous (Lx=1e38-1e39 erg/s) recurrent supersoft X-ray source (SSS)
currently in outburst. The source, located in NGC300, has a 5.4-hr
period and is ultraluminous in the high state. In AO-7, we obtained a
Chandra HRC-I observation to locate the position in order to search for
the optical counterpart in archival HST and VLT images. However, the
source was off with a 99% upper limit of 3.5e37 erg/s (ATel#1560).
NGC300 was observed with Swift on 2008 5/20, 6/4, and 6/19. The SSS was
clearly detected with XRT in all observations and all the source
photons are from below 0.7 keV, consistent with a SSS. The 0.2-2 keV
unabsorbed luminosity is about 1.5-2e38 erg/s (ATel#1560). If the
companion can be identified, we can set a strong constraint on the
donor and conclude whether the compact object is an IMBH. It would also
provide important information about the formation of SSS in a black
hole binary system.

Sequence Number: 400933

Title : The cold neutron star in the long-duration transient AX J1754.2-2754
PI: Keek
Abstract: As written in Atel#1575, J1754j went to quiescence after a long
outburst. The source is an ultra-compact X-ray binary. The long
outburst duration and ultra-compact nature make this source resemble
H1905+000. The current Chandra non-detection, based on a 2 ks-long
observation, shows that J1754 is very faint already given that the long
outburst duration facilitates a high neutron star crust temperature.
The low flux and the relatively high N_H forego triggering the Wijnands
et al. ToO (which is based on measuring neutron star X-ray spectra).
Instead, we propose to obtain one 30 ks observation to search for J1754
in quiescence. In 30 ks we would reach a flux limit of ~5E-15 erg cm-2
s-1, yielding a luminosity limit of 5E31 erg/s. A non-detection would
make J1754 the second UCXB to be very cold (after H1905) suggesting
that the UC nature and hence the composition of the accreted material
is important for setting the NS temperature and or the cooling rate.

Sequence Number: 400932

Title : Chandra follow up of XTE J1719-291
PI: Sala
Abstract: XTE J1719-291 is a new, faint X-ray transient, discovered with RXTE/PCA
on March 21 (ATel#1442). PCA monitoring indicated an initial rise
followed by a delcine. Swift/XRT follow up on 30 March and April 3
provided the position with an uncertainty of 3.8 arcsec and confirmed
the decline (ATel#1451,#1467). The XRT spectrum was fit with an
absorbed powerlaw with nH=6e21cm-2 and a photon index of 3. A more
recent Swift observation on April 9 showed a re-brightening by a factor
10 and a hardening of the spectrum (ATel#1467), with a photon index of
2.5 and a 2-10 keV absorbed flux of 1.4e-11 erg/cm2/s. There are no
known objects in Simbad or ROSAT catalogues within the XRT error
circle. To identify the IR counterpart, we observed XTE J1719 on April
11 in 7 bands (grizJHK) with GROND at the MPI/ESO 2.2m telescope at La
Silla. We find 13 near-infrared sources in the XRT error circle. The
transient properties are unusual, so it's unclear what kind of NIR
variability is to be expected.

Sequence Number: 400931

Title : A rare transient in M81: a merger event?
PI: Jonker
Abstract: A recently discovered optical transient (OT) in M81 (atel #1330) can
not be explained by a known transient event, it is a very good merger
candidate (NS-NS, BH-NS). Distinguishing properties are: decay rate is
too fast for a NOVA, optical brightness is too low for a SN (MV=-7.3),
the K-band magnitude and NIR colors rule out a foreground flaring
M-dwarf, the source is too bright for an transient X-ray binary. We
searched the Chandra archive for the presence of an X-ray source. None
was found even after stacking all the ACIS data. A transient X-ray
source was observed on 2000-05-07 in Chandra OBS ID 735 close to the
position of the OT. However, the distance to the position of the OT was
2.8 arcsec which is too much for the two events to come from the same
source. The optical decay time matches the predicted decay time for a
merger event (Sylvestre 2003). If this OT is a merger event, X-rays are
predicted to be emitted due to either fall back or radio-active decay
of ejected material.

Sequence Number: 200569

Title : X-ray emission from the pre-main sequence star ZCMa during a FUOri-type
outburst
PI: Stelzer
Abstract: We propose for the first X-ray spectrum of an FUOri object during
outburst. The FUOR phenomenon is associated with a sudden increase of
the accretion rate in some pre-main sequence (PMS) stars, possibly due
to changes in the magnetic field. In the first X-ray survey of FUORs
Skinner et al. (2007) have detected two of four targets. None of them
was in outburst at the time. The typical two-temperature spectrum of a
PMS star requires in the case of FUOri different absorptions for the
soft and hard components (Skinner et al. 2006). Our target ZCMa is a
young F-type FUOR. In Feb 2008 ZCMa started its so far largest
outburst, with a further enhancement ~2 weeks ago. In May 2008 we have
detected its magnetic field. Now we aim at an X-ray detection of ZCMa
in its `super-outburst'.

Sequence Number: 200568

Title : The current X-ray status of the planet bearing host star 51 Peg
PI: Schmitt
Abstract: In a 50 ksec XMM pointing we found a X-ray flux drop of >20 (compared
to ROSAT) for 51 Peg, the most famous planet-bearing host star. 51 Peg
is of very low activity and its chromospheric flux has been stable over
many years. A dramatic (downward) change in soft X-ray flux has never
been observed before in any star with the possible exception of Alpha
Cen. It is important to check how long this extremely low activity
state of 51 Peg persists. The X-ray surface flux derived from the XMM
lies more than one order of magnitude below expectation. A possible
solution is a coronal temperature change. An HRC pointing with its
larger low energy sensitivity will show if there is undetected flux in
the 0.1-0.2 keV band or if 51 Peg's corona has almost completely
disappeared from the X-ray world.

Sequence Number: 200568

Title : The current X-ray status of the planet bearing host star 51 Peg
PI: Schmitt
Abstract: In a 50 ksec XMM pointing we found a X-ray flux drop of >20 (compared
to ROSAT) for 51 Peg, the most famous planet-bearing host star. 51 Peg
is of very low activity and its chromospheric flux has been stable over
many years. A dramatic (downward) change in soft X-ray flux has never
been observed before in any star with the possible exception of Alpha
Cen. It is important to check how long this extremely low activity
state of 51 Peg persists. The X-ray surface flux derived from the XMM
lies more than one order of magnitude below expectation. A possible
solution is a coronal temperature change. An HRC pointing with its
larger low energy sensitivity will show if there is undetected flux in
the 0.1-0.2 keV band or if 51 Peg's corona has almost completely
disappeared from the X-ray world.

Sequence Number: 200526

Title : The physics of flares in young stellar objects
PI: Micela
Abstract: Flares are the most extreme manifestation of stellar activity. Magnetic
reconnection produces fast electrons that hit the stellar surface to
produce chromospheric material evaporation. Non-thermal heating shows
up as impulsive flares in optical and hard X-rays, and evaporation as
longer soft X-ray flares. Multi-band observations covering thermal and
non-thermal components are essential to understand the physics of
flaring. The CoRoT space telescope will continuously observe the star
forming region NGC2264 for 20 days in March 2008 in the optical with
unprecedented photometric precision and with a temporal resolution of
10s of sec, ideal for the detection of impulsive events. We ask for two
100ksec observations in the two most populated cluster regions during
the CoRoT observation to simultaneously study the non-thermal (CoRoT)
and the thermal (Chandra) components of flares. 100s of flaring sources
have already been detected in a single ACIS field in NGC2264 (Flaccomio
et al. 2006).

Sequence Number: 200526

Title : The physics of flares in young stellar objects
PI: Micela
Abstract: Flares are the most extreme manifestation of stellar activity. Magnetic
reconnection produces fast electrons that hit the stellar surface to
produce chromospheric material evaporation. Non-thermal heating shows
up as impulsive flares in optical and hard X-rays, and evaporation as
longer soft X-ray flares. Multi-band observations covering thermal and
non-thermal components are essential to understand the physics of
flaring. The CoRoT space telescope will continuously observe the star
forming region NGC2264 for 20 days in March 2008 in the optical with
unprecedented photometric precision and with a temporal resolution of
10s of sec, ideal for the detection of impulsive events. We ask for two
100ksec observations in the two most populated cluster regions during
the CoRoT observation to simultaneously study the non-thermal (CoRoT)
and the thermal (Chandra) components of flares. 100s of flaring sources
have already been detected in a single ACIS field in NGC2264 (Flaccomio
et al. 2006).

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 701583

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of 50)
and the launching of superluminal radio components. Determination of
which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701582

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of 50)
and the launching of superluminal radio components. Determination of
which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701581

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of 50)
and the launching of superluminal radio components. Determination of
which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701580

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of 50)
and the launching of superluminal radio components. Determination of
which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701579

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of 50)
and the launching of superluminal radio components. Determination of
which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701578

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of 50)
and the launching of superluminal radio components. Determination of
which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701577

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of 50)
and the launching of superluminal radio components. Determination of
which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701576

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of 50)
and the launching of superluminal radio components. Determination of
which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 600649

Title : Constraining the Geometry and Energetics of the Exceptionally Energetic
GRB070125
PI: Frail
Abstract: The IPN and Swift-localized GRB070125, the brightest radio afterglow
seen in almost four years, exhibits a steep spectrum from GHz
frequencies up to ~1 mm, indicating a dense local environment (n >~ 100
cm^-3) and an extreme isotropic-equivalent afterglow energy (~10^54
erg). Depending solely on the angle of collimation (i.e. "jet opening
angle") derived for this burst, it may easily become the highest-energy
release GRB seen to date, straining the capacity of collapsar models
and sounding the death knell for the "standard energy reservoir" of
GRBs (Frail et al., ApJ, 562, 2001). We have an extensive set of
optical and radio data for this burst that show a likely jet break at
t~5 days; at this same epoch, the X-ray afterglow fades below the
detection limit of Swift. We request a single 30-ksec observation with
Chandra to distinguish jet-break from no-break models for the X-ray
emission, and therefore to enable measurement of the prompt and
afterglow energies for this remarkable event.

Sequence Number: 501009

Title : A radio and X-ray study of Type Ic SN2007gr at < 10 Mpc
PI: Soderberg
Abstract: The new Type Ic SN2007gr at just 10 Mpc was spectroscopically
identified on Aug 16 2007 at an estimated age of a few days since
explosion. Our radio follow-up on Aug 17 shows a radio transient
coincident with the optical position. Simultaneous radio (synchrotron)
and X-ray (synchrotron,thermal,and/or IC) observations of SNe Ibc trace
the interaction of the fastest ejecta with the circumstellar material
and have been limited to just a handful of events to date. The
combination of radio and X-ray data breaks model degeneracies and
enables the parameters of the fastest ejecta to be revealed.
Extrapolating the optically thin radio emission as nu^-0.7 to the X-ray
band we expect at a count rate of roughly 0.0005 cps. We therefore
request 20 ksec of DDT within 1-2 weeks for our radio/X-ray study of
this very nearby SN.

Sequence Number: 500822

Title : Localization of SN 2005kd
PI: Pooley
Abstract: We propose to observe the Type IIn (narrow emission line) SN 2005kd. A
recent optical spectrum shows it is similar to the extremely X-ray
luminous SN 1988Z (in fact, it has a higher eq. width of H\alpha than
88Z did at a similar epoch). A recent Swift observation detected
emission consistent with the SN at Lx = 1.4e41 erg/s (d=61.5 Mpc).
Because the SN is only 5" from the nucleus of its host galaxy, and
because there may be ULXs also present in the host, we would like to
determine the amount of "contamination" in the Swift emission to the
10% level. In 3ks, we will detect ~75 counts from 05kd, and ~7 counts
from something that's 10% the flux. This will allow a conclusive
association of the Swift source with the SN, as well as provide a
measure of possible contaminating sources. We also plan on proposing
for a deep XMM observation to obtain a high quality spectrum (it will
be visible in a few weeks), and in this case as well, a measure of
contamination will be invaluable.

Sequence Number: 500821

Title : Confirmation of a new Isolated Neutron Star in the ROSAT All Sky
Survey
PI: Rutledge
Abstract: The 7 known X-ray dim isolated neutron stars (INSs) were all discovered
from the ROSAT all-sky survey between 1995 and 1999. We may have
discovered an important one: the first INS in the halo. 1RXS J1412+7922
is important because: (1) its blackbody spectrum is hotter than any
known INS (235+/-45 eV; compared with 118+/-13 for the next hottest);
(2) its low flux (0.05 PSPC c/s) and high temperature make it the most
distant known INS (8.2 kpc, compared with 2.3 kpc for RX J0806-4123;
the remaining six are <1 kpc); and (3) its high galactic latitude gives
it a galactocentric position (R_c=13.4, z=4.9 kpc) in the galactic
halo. J1412 cannot be powered by accretion (no ISM in the halo); if
cooling, it must be <1e6 yr old, giving a velocity of >4900 km/sec
(from the Galactic plane), the highest ever observed. Otherwise, a
cooling time of >1e7 yrs is required, the longest ever observed.

Sequence Number: 500820

Title : Repudiation or Confirmation of an Enormous Glitch in a Magnetar
PI: Woods
Abstract: On Sep 21, 2006, a bright X-ray burst was recorded (GCN 5581) from the
newly discovered AXP CXO J1647-45. The burst was accompanied by a large
flux increase, spectral hardening, a dramatic pulse profile change, and
a reported glitch of dnu/nu ~1e-4 (ATEL 932) whose amplitude is
unprecedented for any neutron star. Using 4 CXO observations between
9/27 and 10/28, we have been able to track the spectral changes, pulse
morphology evolution, and provide the first measurement of the
spin-down rate and thus magnetic field strength of CXO J1647-45 (ATEL
929). Further analysis of all available X-ray data has brought into
question the reality of the reported glitch. The parameters of this
glitch factor heavily into the physical interpretation of the outburst
and in general, our understanding of the internal structure of
magnetars. We are requesting one additional observation to extend our
phase-coherent timing solution to confirm the measured spin-down rate
and better anchor our ephemeris.

Sequence Number: 400928

Title : Which M15 X-ray Source Brightened?
PI: Heinke
Abstract: We have recently discovered, in archival data, a very faint X-ray
transient in M15 (2004 and 1994 outbursts at ~5e33 ergs/s), in addition
to the two known bright LMXBs. We have just become aware that the RXTE
ASM has recently (June-July) registered an outburst from M15
(=X2127+119), with countrates reaching 4 times normal. 3-4 smaller
outbursts have been seen by RXTE, but this is the brightest yet seen.
Both M15 persistent LMXBs show stable mass transfer. We suspect that
the recent outburst may be due to a third source, possibly the newly
identified transient, or perhaps another source. We request a short
10-ksec HRC-I observation of M15 sometime over the next 10 days to
identify if another X-ray source, besides the two bright LMXBs, is
responsible for the recent brightening of M15. This will give at least
5 counts from all sources with Lx(0.5-10)>2.6e32 ergs/s (for photon
index 1.7).

Sequence Number: 400691

Title : RFO with Chandra of the newly discovered Millisecond X-ray Pulsar
(MsXP) SWIFT J1756.9-2508
PI: Di Salvo
Abstract: According to the recycling scenario MsXPs are the progenitors of radio
ms pulsars.The recent discovery of the 5.5ms pulsar in the X-ray
transient SWIFT J1756.9-2508(ATEL #1108)brought to 8 the number of
sources of this class.Timing techniques applied to high temporal
resolution data allows the direct measurement of the rotational
behavior of the compact object under the effect of accretion,leading to
an unique opportunity to answer to the long lasting dispute about
accretion models for fast rotators(Burderi 2006,ApJL,653,133;Burderi
2007,ApJ,657,961(BD);Papitto 2007,MNRAS,375,971).However timing
analysis is able to produce reliable results only when an accurate
position of the source is known(BD).The excellent Chandra spatial
resolution will provide an unique accuracy on this key parameter(Krauss
2005,ApJ,627,910(KR))to further investigate the rotational behavior of
these objects.Chandra will also give us the possibility to study a high
energy resolution spectrum of this source.

Sequence Number: 400690

Title : Observing flaring activity in the new source SWIFT J195509.6+261406
PI: KANBACH
Abstract: SWIFT/BAT triggered on a new source on 10 June, 2007 20:52:26 UTC (GCN#
6489, Pagani et al.). The reported position was promptly observed in
optical light and, after some delay, with the XRT. Bright short optical
outbursts (10s timescales, amplitudes >3 mag) were discovered in the
first hour after the trigger and again during the night June 11-12,
2007 (GCN# 6492,6508, Stefanescu et al.). SWIFT/XRT confirmed the
position of the optical counterpart and the flaring behaviour
(amplitudes up to 25 mCrab). We propose to perform CXO-HETG
spectroscopy of the source to determine the emission process through
the spectrum, and thus the nature of this object. It could be a fast,
giant X-ray transient, SGR or AXP, or a thermonuclear X-ray burster.

Sequence Number: 400689

Title : X-ray jets in CirX-1
PI: Jonker
Abstract: CirX-1 is a neutron star (Tennant et al 1986a,b). The X-ray and radio
flux of CirX-1 have gradually decayed over the last few years. Recently
the radio flux has increased dramatically (ATel 985). The source has
returned to the low X-ray-flux high radio-flux state as found in the
1970-80ties. On March 6 Fender observed a radio jet using ATCA at 2"
from the core. Interestingly, the position angle of the radio jet has
changed. The large radio flares suggest that major ejection events take
place. We propose a 50 ksec HRC-I observation to take advantage of the
current favorable source/jet count rate ratio to search for an X-ray
counterpart to the new radio jet emission. We assumed that the X-ray
flux and spectrum of a jet is the same as the X-ray jet observed in XTE
J1550-564. For the X-ray flux of CirX-1 we took the value from our
SWIFT-XRT ToO observation of March 19. We simulated with ChaRT/marx
that even a jet placed at a distance of 0.75" is detectable.

Sequence Number: 400688

Title : X-ray jets in CirX-1
PI: Jonker
Abstract: CirX-1 is a neutron star (Tennant et al 1986a,b). The X-ray and radio
flux of CirX-1 have gradually decayed over the last few years. Recently
the radio flux has increased dramatically (ATel 985). The source has
returned to the low X-ray-flux high radio-flux state as found in the
1970-80ties. On March 6 Fender observed a radio jet using ATCA at 2"
from the core. Interestingly, the position angle of the radio jet has
changed. The large radio flares suggest that major ejection events take
place. We propose a 50 ksec HRC-I observation to take advantage of the
current favorable source/jet count rate ratio to search for an X-ray
counterpart to the new radio jet emission. We assumed that the X-ray
flux and spectrum of a jet is the same as the X-ray jet observed in XTE
J1550-564. For the X-ray flux of CirX-1 we took the value from our
SWIFT-XRT ToO observation of March 19. We simulated with ChaRT/marx
that even a jet placed at a distance of 0.75" is detectable.

Sequence Number: 100071

Title : Utilizing the exceptional outburst of Comet 17P/Holmes for probing the
solar wind at 2.5 AU
PI: Dennerl
Abstract: We propose to utilize the extreme outburst of Comet 17P/Holmes for
novel X-ray studies with Chandra. Due to the nature of the outburst, we
expect the gas coma to be collisionally thick to charge exchange,
providing the maximum surface brightness. At a heliocentric distance of
2.5 AU, 1.0 AU more than any other comet observed with Chandra, it will
not only allow us to probe the solar wind at a far distance, but it
will also provide an unprecedented viewing geometry - we will see the
comet from almost the direction as the incident solar wind. Thus, by
utilizing the high spatial resolution of Chandra, it should be possible
to explore the spectral evolution across the face of the coma. The
ecliptic latitude of the comet is 19 deg, so that there is a
possibility that this will become the first Chandra observation of a
comet which is interacting with the polar solar wind or in the
transition zone between the ecliptic and polar winds.

Sequence Number: 100071

Title : Utilizing the exceptional outburst of Comet 17P/Holmes for probing the
solar wind at 2.5 AU
PI: Dennerl
Abstract: We propose to utilize the extreme outburst of Comet 17P/Holmes for
novel X-ray studies with Chandra. Due to the nature of the outburst, we
expect the gas coma to be collisionally thick to charge exchange,
providing the maximum surface brightness. At a heliocentric distance of
2.5 AU, 1.0 AU more than any other comet observed with Chandra, it will
not only allow us to probe the solar wind at a far distance, but it
will also provide an unprecedented viewing geometry - we will see the
comet from almost the direction as the incident solar wind. Thus, by
utilizing the high spatial resolution of Chandra, it should be possible
to explore the spectral evolution across the face of the coma. The
ecliptic latitude of the comet is 19 deg, so that there is a
possibility that this will become the first Chandra observation of a
comet which is interacting with the polar solar wind or in the
transition zone between the ecliptic and polar winds.

Sequence Number: 100071

Title : Utilizing the exceptional outburst of Comet 17P/Holmes for probing the
solar wind at 2.5 AU
PI: Dennerl
Abstract: We propose to utilize the extreme outburst of Comet 17P/Holmes for
novel X-ray studies with Chandra. Due to the nature of the outburst, we
expect the gas coma to be collisionally thick to charge exchange,
providing the maximum surface brightness. At a heliocentric distance of
2.5 AU, 1.0 AU more than any other comet observed with Chandra, it will
not only allow us to probe the solar wind at a far distance, but it
will also provide an unprecedented viewing geometry - we will see the
comet from almost the direction as the incident solar wind. Thus, by
utilizing the high spatial resolution of Chandra, it should be possible
to explore the spectral evolution across the face of the coma. The
ecliptic latitude of the comet is 19 deg, so that there is a
possibility that this will become the first Chandra observation of a
comet which is interacting with the polar solar wind or in the
transition zone between the ecliptic and polar winds.

Sequence Number: 600607

Title : Accurate X-ray position of a possible >10^41 erg/s ULX: evidence for an
intermediate-mass black hole?
PI: Miniutti
Abstract: We have detected with XMM-Newton an off-nuclear ULX candidate in the
D25 ellipse of a spiral galaxy at 90 Mpc. If at 90 Mpc, its 0.5-10 keV
luminosity is 1.3x10^41 erg/s, the most luminous ULX ever detected. The
probability of it being a background AGN is very low based on standard
logN-logS (<0.7%) and even lower if the minimum X-ray to Optical flux
ratio (>60) is considered. The only available HST image shows several
possible counteparts in the XMM error box. We request a 7ks Chandra
ACIS-S exposure to measure the X-ray position with high accuracy, which
will allow us to identify the counterpart (if any) from HST+Chandra and
to organize the optimal follow-up strategy. The Chandra obs by itself
may exclude that the ULX is a background AGN if the HST counterpart is
identified, allowing us to compute a precise X-ra to Optical ratio
which, if > 100 (as for the large majority of possible counterparts),
would exclude the AGN hypothesis.

Sequence Number: 500817

Title : Accurate position measurement of the Isolated Neutron Star RBS1774
PI: Zane
Abstract: We request a 1ks DDT pointing of the Isolated Neutron Star (INS)
RBS1774, to obtain an accurate determination of the X-ray position.
Position measurements of INSs are of paramount importance for an exact
identification of the optical counterpart: it provides vital
information on the SED, on the cause of the X-ray emission, and, over a
longer term, paves the way to the determination of proper motion and
distance; providing crucial informations on the INS surface temperature
and magnetic field distribution, kick velocity and energetics, which
are still largely unknown. We have recently observed the RBS1774 field
with the VLT, the Magellan telescope and with Keck. Several sources
appear in the XMM error box of the INS and even more are expected to be
detected by deeper VLT images, just requested, that will push the
detection limit down to a V=28. A Chandra HRC-I accurate position is
necessary to reliably determine RBS1774 counterpart.

Sequence Number: 500816

Title : The Extreme Supernova 2006gy
PI: Pooley
Abstract: We propose to observe the Type IIn (narrow emission line) SN 2006gy in
NGC 1260. Its optical spectrum (CBET/IAUC submitted) show it is similar
to the extremely X-ray luminous SN 1988Z, which was observed at
Lx=10^41 erg/s at an age of 6.5 yr. It is unknown what the early-time
(first few weeks to months) Lx of such a SN would be. Past attempts at
early X-ray detections (2005bx, 2005db) have given only upper limits
(but follow-ups have been approved), but the class is likely not
homogenous. The extreme optical luminosity (M_V = -22) makes this SN
stand out even among the IIn's (an already unusual class of objects).
The astrometry will be crucial to resolving the SN from possible
nuclear activity. Two X-ray sources within 2.5 arcmin of 2006gy (found
in ObsID 5597) have 2MASS counterparts. They have fluxes of 5.1e-15 and
2.1e-14 (cgs). Our request of 30 ks is based on localizing these
sources well enough (getting 25-30 cts) to achieve ~<0.2" X-ray/2MASS
astrometry.

Sequence Number: 500815

Title : X-Ray Emission from the Type Ib SN 2006jc
PI: Immler
Abstract: An X-ray source is detected at the position of the SN in a 3.4 ks Swift
XRT obs from 2006-10-13 16:10 UT with a flux and lum of 1.0+/-0.4 E-13
ergs/cm/cm/s and 6.7+/-2.7 E39 ergs/s (0.2-10 keV). The UV-V colors are
extremely blue, similar to the X-ray bright SN IIP 2006bp. The Swift
UVOT data show that the SN is very bright in the opt and especially in
the UV (ATel 916), likely a result of the shock interaction with dense
CSM, confirming that the X-rays are due to the SN. Due to the large PSF
of the XRT (18 HPD), and an offset of the SN of 11" W and 7" S of the
host galaxy, UGC 4904, XRT data do not allow us to unambiguously
associate the X-ray source with the SN, even at higher photon
statistics. No further Swift obs will be obtained due to Sun angle
constraints. The RASS shows no X-ray source at the position of the host
galaxy. Therefore, the association of the X-ray source with the SN is
strong and the Chandra obs could establish SNe Ib, for the first time,
as X-ray sources.

Sequence Number: 500814

Title : Monitoring a Recovering AXP and Measuring Pdot
PI: Kaspi
Abstract: Anomalous X-ray Pulsar (AXP) outbursts are rare, occuring roughly once
per decade per src, and offer rare opportunities to constrain the
poorly understood physics of magnetars. Recently AXP CXO
164710.2-455216.9 went into outburst and we were granted 3 ToO obs with
CXO. These obs together, via phase-coherent timing, set the best
constraint on the unknown Pdot, which implies magnetic field (3sig)
<2e14 G. This is low for a magnetar but not yet a problem. We request 1
more 25 ks DDT obs of AXP CXO 164710.2-455216.9. This obs will continue
to monitor it back to quiescence to distinguish between proposed
recovery models, and, importantly, if scheduled near Oct 30, will
either detect or put an unprecedented upper limit on Pdot, via phase
connection with previous CXO ToO obs. If no Pdot is detected, we will
constrain B<5e13G (3sig), lower than for any other known magnetar
(lowest known 6e13G), and perplexingly below B measured for some
ordinary, non-magnetar neutron stars.

Sequence Number: 500693

Title : Chandra observation of the Type Ia SN 2005ke
PI: Immler
Abstract: The longest Swift obs. obtained to date (258-ksec) on a SN gives
evidence that the Type Ia SN 2005ke has been detected in X-rays, at a
low level of significance (3-3.5 sigma, CBET 387). See
http://lheawww.gsfc.nasa.gov/users/immler/SN2005ke/Immler_fig1.jpg for
Swift UV and XRT X-ray image. No SN Ia has ever been detected in
X-rays. The Swift UVOT UV lightcurve
http://lheawww.gsfc.nasa.gov/users/immler/SN2005ke/Immler_fig3b.jpg
shows a UV excess starting around 35d after the explosion with respect
to SN Ia lightcurve templates, coinciding with the onset of X-ray
emission. The detection of UV excess is independent confirmation that
the X-rays are from the interaction of the SN shock with CSM as the UV
emission is due to the Mg II emission line at 280 nm. We request a
15-ksec Chandra ACIS-S observation of the nearby (20.7 Mpc) Type Ia SN
2005ke to unambigiously associate the detected Swift X-ray source with
the SN.

Sequence Number: 500692

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.

Sequence Number: 500691

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.

Sequence Number: 500690

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.

Sequence Number: 500689

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.

Sequence Number: 400680

Title : Probing the true nature of the microquasar candidate LS I +61 303
PI: Perez-Torres
Abstract: The radio-emitting x-ray binary LSI +61 303 has been recently detected
at TeV energies. Two scenarios have been proposed to account for this
high-energy emission, namely an accretion/jet mechanism (microquasar),
and an interacting pulsar wind model. We propose to observe LSI +61 303
with Chandra as part of a multi-wavelength campaign that includes
simultaneous observations with MAGIC (gamma-rays), MERLIN (radio), and
Calar Alto (infra-red). (Those observations have been approved for the
nights of the 25 and 26 October 2006.) The proposed observations will
be the first such simultaneous, multiwavelength effort on this object,
and the geometrical, spectral and temporal features of its radio
emission will be studied and correlated with those in the infra-red,
X-ray and, TeV regimes. The results will help to elucidate the true
nature of LS I +61 303 and the acceleration mechanisms that produce the
high energy emission.

Sequence Number: 400561

Title : Is PSR B1931+24 the golden source for the accretion regimes testing?
PI: Rea
Abstract: Very recently the discovery of an intermittent radio pulsar was
reported on Science (Kramer et al.2006,astro-ph/0604605). PSR B1931+24
has the surprising peculiarity of being a 813ms radio-pulsar for ~5d
and being radio quiet for the following 25-35d, periodically. The
pulsar spin slows down 50% faster when the pulsar is on than when is
off. The ~30d periodicity and the weird spin-down behaviour of this
radio activity remind what is expected for a pulsar in a binary system
spinning near the equilibrium period in an eccentric ~30d orbit: at the
apastron the low wind accretion rate allows the radio pulsar regime,
while at the periastron the neutron star is radio-quiet because
accreting and emitting in the X-rays. This might be the linking object
between the X-ray binaries and the radio pulsar binaries, a golden
source for finally testing the accretion regimes.

Sequence Number: 400559

Title : Searching for the optical/IR counterpart of the transient X-ray pulsar
Swift J1626.6-5156
PI: Homan
Abstract: The transient 15.3 sec X-ray pulsar Swift J1626.6-5156 was discovered
late 2005. It shares some properties with anomalous X-ray pulsars,but
is most likely a 'normal' X-ray pulsar with some unusual properties.
Determining the nature of the companion star could shed light on the
mode of accretion (disk vs. wind), which in turn might help explain
some of the unusual properties. Recent IR observations seem to rule out
a HMXB as the optical counterpart of the source (ATel 713). Further
attempts at identifying the optical counterpart are hampered by the
uncertainty in the position of the source. The most accurate position
has 90% an error circle of ~3.5 arcseconds (ATel 688). However,
reliable counterparts to other X-ray sources have been found outside
Swift/XRT error circles before (see e.g. Atel 712). The main goal of
the proposed short HRC observation is to improve on the Swift/XRT
position and thereby provide better constraints for identifying a
possible optical/IR counterpart.

Sequence Number: 400558

Title : Eruptive Behavior in HD 109962: A compact object interacting with a W
UMa system?
PI: Walter
Abstract: HD 109962 (vsnet-alert 8794) is in outburst. It is a 0.89 day W UMa
eclipsing binary. It is not a known X-ray source. What makes HD 109962
of interest is that it shows ~0.8 mag outbursts of ~40 day duration
about once a year (see http://ar.geocities.com/varsao/NSV_19448.htm).
The latest outburst began about 12/26/05. A red spectrum on Jan 13.2
shows a P Cygni H-alpha line, indicative of wind emission. The blue
spectrum on Jan 16.2 is astounding. Superposed on a normal F2V spectrum
is a large He II 4686 emission line (EW = -2.9 A). He II 4686 requires
a source of highly ionizing radiation. It is certainly not normally
seen in F2V stars or W UMa systems. The ~periodic nature of the
outbursts suggests a model akin to Cir X-1, with a compact object on a
highly elliptical orbit that penetrates the wind from the W UMa system.
It should be a bright X-ray source during the outburst. If so, followup
observations will provide a unique probe of the wind of a contact
binary system.

Sequence Number: 300179

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.

Sequence Number: 300178

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.

Sequence Number: 300177

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.

Sequence Number: 300172

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985 It was observed by EXOSAT. It's outburst commenced on Jan. 26
(IAUC 4030, 4031, 4036). EXOSAT observed RS Oph between 18h00 and 23h00
UT on 1985 Mar. 22. Preliminary analysis indicated that the x-ray
spectrum was soft and absorbed. Fits to a thermal bremsstrahlung model
yielded a temperature of 0.75 keV and an absorbing column density of ~
10**21 atoms cm**-2. The flux at Earth in the 0.1-6.0-keV band was
estimated to be 4 x 10**-10 erg cm-**2 s**-1. This was taken from an
IAU Circular by Cordova and Mason in 1985. It has an extremely rapid
decline in Xrays which are probably caused by a shock moving through a
red giant atmosphere.

Sequence Number: 200460

Title : A(nother) Star is Born: the Early Evolution of a Pre-main Sequence
Accretion Burst
PI: Kastner
Abstract: Accretion processes produce X-ray emission in a wide variety of
astrophysical environments, yet the link between pre-main sequence
(PMS) star accretion and X-ray emission remains tenuous at best.
Undoubtedly the most convincing example of accretion-driven PMS X-ray
emission is that of V1647 Ori; Chandra observations obtained over the
(two-year) duration of the optical/IR outburst of this PMS star
revealed that its X-ray flux and hardness closely tracked the dramatic
rise and subsequent decline of its accretion luminosity (Kastner et al.
2004, Nature, 430, 429 and 2006, ApJ, 648, L43). These results for
V1647 Ori suggest that X-ray emission from erupting low-mass, PMS stars
is diagnostic of the degree of star-disk magnetic field reorganization
during major ("FUor"- or "EXor"-type) accretion events. Prompt
post-outburst observations of additional erupting PMS stars are
required to test this hypothesis.

Sequence Number: 100067

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May 2006
than any comet yet detected in the x-rays. We propose a total of 20 ks
observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.

Sequence Number: 100066

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May 2006
than any comet yet detected in the x-rays. We propose a total of 20 ks
observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.

Sequence Number: 100065

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May 2006
than any comet yet detected in the x-rays. We propose a total of 20 ks
observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.

Sequence Number: 100064

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May 2006
than any comet yet detected in the x-rays. We propose a total of 20 ks
observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.

Sequence Number: 100063

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May 2006
than any comet yet detected in the x-rays. We propose a total of 20 ks
observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.

Sequence Number: 701180

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started an
all sky survey with INTEGRAL. So far half of the sky at |b|>5d has been
scanned and about 70 sources have been detected above 1 mCrab limit.
80% of them are known bright AGN. 8 objects are unidentified and absent
from the Rosat All-Sky Survey and AGN catalogs. They are likely
obscured AGN. Short Chandra exposure of their 6' error boxes will
provide unambiguous identification and absorption columns. This will
enable immediate optical follow up and assessment of chosen survey
strategy. Being among brightest extragalactic objects, the targets are
good for future detailed study with Chandra and other observatories.

Sequence Number: 701179

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started an
all sky survey with INTEGRAL. So far half of the sky at |b|>5d has been
scanned and about 70 sources have been detected above 1 mCrab limit.
80% of them are known bright AGN. 8 objects are unidentified and absent
from the Rosat All-Sky Survey and AGN catalogs. They are likely
obscured AGN. Short Chandra exposure of their 6' error boxes will
provide unambiguous identification and absorption columns. This will
enable immediate optical follow up and assessment of chosen survey
strategy. Being among brightest extragalactic objects, the targets are
good for future detailed study with Chandra and other observatories.

Sequence Number: 701178

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started an
all sky survey with INTEGRAL. So far half of the sky at |b|>5d has been
scanned and about 70 sources have been detected above 1 mCrab limit.
80% of them are known bright AGN. 8 objects are unidentified and absent
from the Rosat All-Sky Survey and AGN catalogs. They are likely
obscured AGN. Short Chandra exposure of their 6' error boxes will
provide unambiguous identification and absorption columns. This will
enable immediate optical follow up and assessment of chosen survey
strategy. Being among brightest extragalactic objects, the targets are
good for future detailed study with Chandra and other observatories.

Sequence Number: 701177

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started an
all sky survey with INTEGRAL. So far half of the sky at |b|>5d has been
scanned and about 70 sources have been detected above 1 mCrab limit.
80% of them are known bright AGN. 8 objects are unidentified and absent
from the Rosat All-Sky Survey and AGN catalogs. They are likely
obscured AGN. Short Chandra exposure of their 6' error boxes will
provide unambiguous identification and absorption columns. This will
enable immediate optical follow up and assessment of chosen survey
strategy. Being among brightest extragalactic objects, the targets are
good for future detailed study with Chandra and other observatories.

Sequence Number: 701176

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started an
all sky survey with INTEGRAL. So far half of the sky at |b|>5d has been
scanned and about 70 sources have been detected above 1 mCrab limit.
80% of them are known bright AGN. 8 objects are unidentified and absent
from the Rosat All-Sky Survey and AGN catalogs. They are likely
obscured AGN. Short Chandra exposure of their 6' error boxes will
provide unambiguous identification and absorption columns. This will
enable immediate optical follow up and assessment of chosen survey
strategy. Being among brightest extragalactic objects, the targets are
good for future detailed study with Chandra and other observatories.

Sequence Number: 701175

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started an
all sky survey with INTEGRAL. So far half of the sky at |b|>5d has been
scanned and about 70 sources have been detected above 1 mCrab limit.
80% of them are known bright AGN. 8 objects are unidentified and absent
from the Rosat All-Sky Survey and AGN catalogs. They are likely
obscured AGN. Short Chandra exposure of their 6' error boxes will
provide unambiguous identification and absorption columns. This will
enable immediate optical follow up and assessment of chosen survey
strategy. Being among brightest extragalactic objects, the targets are
good for future detailed study with Chandra and other observatories.

Sequence Number: 701174

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started an
all sky survey with INTEGRAL. So far half of the sky at |b|>5d has been
scanned and about 70 sources have been detected above 1 mCrab limit.
80% of them are known bright AGN. 8 objects are unidentified and absent
from the Rosat All-Sky Survey and AGN catalogs. They are likely
obscured AGN. Short Chandra exposure of their 6' error boxes will
provide unambiguous identification and absorption columns. This will
enable immediate optical follow up and assessment of chosen survey
strategy. Being among brightest extragalactic objects, the targets are
good for future detailed study with Chandra and other observatories.

Sequence Number: 701173

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started an
all sky survey with INTEGRAL. So far half of the sky at |b|>5d has been
scanned and about 70 sources have been detected above 1 mCrab limit.
80% of them are known bright AGN. 8 objects are unidentified and absent
from the Rosat All-Sky Survey and AGN catalogs. They are likely
obscured AGN. Short Chandra exposure of their 6' error boxes will
provide unambiguous identification and absorption columns. This will
enable immediate optical follow up and assessment of chosen survey
strategy. Being among brightest extragalactic objects, the targets are
good for future detailed study with Chandra and other observatories.

Sequence Number: 701172

Title : An accretion eruption in the western nucleus of Arp 299
PI: Nandra
Abstract: Monitoring of starburst galaxies in the NIR at WHT in a search for
supernovae (PI: Meikle), has revealed an extraordinary outburst from
NGC 3690, part of merging, LIG system Arp 299 (IAUC 8477). Subtraction
of a Ks image taken on 2005 Jan 30 from earlier images (most recently
2004 June 5) shows a highly variable source within 0.5 of the iron K_
emitter identified by Chandra as the AGN in NGC 3690 (Ballo et al. ApJ,
600, 634). Such large NIR variability (30%) is generally restricted to
powerful radio-loud QSOs+blazars. What makes this event even more
remarkable is that the AGN in NGC 3690 is usually very weak. The
intrinsic flare is thus likely to be much larger, as the quiescent NIR
emission, which is resolved, is likely dominated by stars. We propose a
Chandra snapshot to confirm the flare and determine its amplitude. It
may be due to a huge accretion event or the rapid formation of a
relativistic jet, heralding NGC 3690 s transition into a fully-fledged
AGN following the merger.

Sequence Number: 500685

Title : Investigating Circumstellar Interaction in the type Ia SN 2005gj
PI: Pooley
Abstract: The supernova 2005gj was just reported (CBET 302) to display the
signatures of circumstellar interaction. This is only the second
detection of hydrogen in the optical spectrum of a type Ia supernova.
The interaction of SN ejecta with surrounding material should give rise
to X-ray emission, as it does in core-collapse SNe. An observation with
Chandra will measure the luminosity, thus determining the strength of
the interaction. Very little is known about the progenitors of Ia SNe.
Because the X-rays are a great probe of the circumstellar material
around a SN, this Chandra observation could shed important light on the
progenitor system.

Sequence Number: 500603

Title : Chandra Observation of the Type IIn Supernova 2005bx
PI: Filippenko
Abstract: We propose to observe the recently discovered Type IIn (narrow emission
line) SN 2005bx. Its optical spectrum (ATEL #475) shows it is similar
to the extremely X-ray luminous SN 1988Z, which was observed at Lx=1e41
erg/s at an age of 6.5 yr. It is unknown what the early-time (first few
weeks to months) Lx of such a SN would be. A simple constant-density
model of the circumstellar (CS) material around 1988Z predicts an Lx of
1e43 erg/s at an age of a few months with a hard spectrum. However, the
CS interaction is complicated, and this naive model may not hold (e.g.,
there could be absorption by the CS gas). It is difficult to make clear
predictions because of the lack of knowledge. A 30 ks obs of 2005bx (at
130 Mpc) will reach a sensitivity of ~1e39 erg/s (4 counts). This early
observation would be unique for this interesting and poorly understood
class of SNe. Chandra may only see 2-3 SNe like this during its
lifetime, and this opportunity should not be missed.

Sequence Number: 500601

Title : GRB050412: The Darkest of the Dark Bursts
PI: Berger
Abstract: Swift localized GRB050412 to few-arcminute precision in real-time while
it was in the night sky over most of the world's major observatories.
While subsequent Swift observations have established the presence of a
fading X-ray afterglow of relatively ordinary flux (GCN 3253), prompt
follow-up observations from UV (GCN 3249) to optical (GCNs 3238, 3239,
3242) to JHK (GCN 3235) - reaching to increasingly deep limits from 7.1
sec to 1 hour after the burst - have established only upper limits to
the afterglow flux in these bandpasses. As with previous events, this
is likely due to some combination of host galaxy extinction and high
redshift; since GRB050412 is the darkest known burst, unusually high
redshift and/or high extinction is indicated. However, the five-arcsec
Swift XRT position will not allow unique identification of a host
galaxy. We therefore propose to make a single Chandra observation to
derive a sub-arcsec position for GRB050412 from its X-ray afterglow.

Sequence Number: 500599

Title : Resolving an X-ray Jet from the Magnetar SGR 1806-20
PI: Kouveliotou
Abstract: On 27 Dec 2004, SGR 1806-20 emitted a giant flare, a once in a century
event with an X-ray peak flux of at least 0.8 erg/cm^2 s. Seven days
later we identified with VLA a bright (172 mJy, 1.4 GHz) expanding
radio source at the location of the SGR, ~500 times brighter than the
radio afterglow seen from SGR 1900+14 following the 1998 August 27
flare. We obtained data with MERLIN separated by 3 days, which show
that within 13 days of the flare a radio structure of angular extent
~100 mas has formed with the peak of the flux displaced ~100 mas
between the two epochs. This elongation immediately suggests a jet
inclined to the line of sight and significantly relativistic, in
analogy with X-ray emission from X-ray binary jets, which have reheated
themselves presumably by the transfer of bulk kinetic energy to
electrons. Discovery of an X-ray jet in a magnetar will provide unique
evidence for the energetics of the shock, the ambient medium and the
B-field of the pulsar.

Sequence Number: 500598

Title : The X-ray Fluence of the SGR 1806-20 Hyperflare
PI: Fox
Abstract: On 17 Dec 2004, SGR 1806-20 emitted the brightest burst ever observed
from a Galactic source. This burst, first reported by the Integral
mission (GCN 2920), saturated detectors on every high-energy satellite.
The current lower limit to its fluence, 0.3 erg cm-2 (GCN 2936), would
make the burst luminosity roughly 10^46 erg, dozens to hundreds of
times brighter than the "giant flares" that have previously been
observed from other SGRs -- bright enough that hyperflares in nearby
galaxies could contribute to the population of short-hard gamma-ray
bursts (GCN 2942). We propose to make the first accurate measurement of
the fluence in this flare by observing the X-ray scattering halos
produced by molecular clouds between Earth and SGR 1806-20; five clouds
with A_V>2 mag are known from radio observations (Corbel & Eikenberry
2004, A&A 419, 191). The X-ray rings from four of these clouds will be
observable with Chandra, allowing four independent estimates of the
fluence of the hyperflare.

Sequence Number: 500597

Title : Searching for atomic and/or cyclotron features in the Giant Flares
decay of SGR 1806-20
PI: Rea
Abstract: On 2004 December 27th a Giant Flare from SRG1806-20(GCN 2920) was
revealed, the 1st ever for this source and the 3rd one from SGRs since
1979.The current event is largely more energetic than the previous ones
a rare opportunity to study its decay with the unprecedented spectral
resolution of Chandra,allowing,among other thing to study the
enviroment of the source through the possible presence of spectral
edges/line(similarly to the study performed on GRBs X-ray
afterglows).The comparison of the source emission properties before and
after the flare (XMM obs.carried out few weeks before the event)will
provide an unprecedented opportunity to constrain the magnetar model
and the neutron stars crustal properties.The possibility of detecting
cyclotron features after the flare will especially be important; in
particular,for this source there was evidence for a cyclotron feature
around 5 keV,revealed by RXTE during a bursting phase.The HETG has the
best available resolution around that energy.

Sequence Number: 400472

Title : Confirmation of the Fading Afterglow From the Short Burst GRB 050709
PI: Frail
Abstract: Seven years after the afterglow detections that revolutionized studies
of the long/soft gamma-ray bursts (LSBs), not even one afterglow of a
short/hard GRB (SHB) has been seen. Theoretical calculations suggest
that SHB afterglows will be much fainter than LSB afterglows, faint
enough that ground-based detections should probably not be expected.
Deep Chandra observations, on the other hand, if made within days of
the burst, should be able to find the X-ray afterglow. This appears to
be the case with the recent GRB050709 in which Chandra observations
conducted 2.5 days after the burst detected a source (GCN 3585). Its
flux is consistent with a t^-1.4 power-law decay from the afterglow
peak observed by the HETE SXC at 100 s after the burst. Spectroscopy
undertaken with Gemini of an optical source near the Chandra position
(GCN 3589) yields a redshift z=0.16. The SHB mystery will be solved if
the Chandra source fades away in time.

Sequence Number: 400470

Title : Search for X-Ray Jets from a Millisecond Pulsar
PI: Chakrabarty
Abstract: The nearby (2.5 kpc) millisecond X-ray pulsar SAX J1808.4-3658 is in
outburst as of June 1 (ATEL 505). In its 1998 outburst, the source
showed both radio emission and an infrared excess about 15-20 days
after the outburst peak, suggestive of synchrotron emission from a jet
(Wang et al. 2001, ApJ, 563, L61). Very few NS jet sources are known
(Sco X-1, as well as SS433 and Cir X-1 if they are NSs), and this
source provides the first opportunity to link jet emission to a pulsar
with known magnetic field strength. At a source distance of only 2.5
kpc (in't Zand et al. 2001, A&A, 372, 916), the HRC angular resolution
of 0.4 arcsec corresponds to a separation of 6 light-days at the
pulsar, providing excellent angular sensitivity to a relativistic
ejection.

Sequence Number: 400469

Title : Outburst spectroscopy of the closest accretion-powered millisecond
pulsar
PI: Galloway
Abstract: The visibility of persistent pulsations in accretion-powered
millisecond pulsars (in contrast to other LMXBs) suggests that surface
spectral features might also be more easily detectable. SAX
J1808.4-3658 is the closest of the three MSPs with H-rich donors; three
more are ultracompact and likely accrete primarily He from degenerate
companions. Surface spectral features may arise from freshly accreted
material and the products of spallation reactions, the rate of which
may be greater for H-rich accretors (L. Bildsten, pers. comm.).
Although no high signal-to-noise HETGS spectrum of SAX J1808.4-3658 has
been taken, an opportunity to obtain such a spectrum has arisen with
the early detection of a new outburst on 1 June (ATel #505). We propose
to observe the source with the HETGS for 22 ks in order to 1) search
for discrete emission and absorption features, 2) characterize the
neutral absorption edges and 3) test for flux and spectral feature
variation at the 2.01 hr orbital period.

Sequence Number: 400468

Title : Periastron Observations of a Massive Eclipsing Pulsar Binary System
PI: McLaughlin
Abstract: The 764-ms pulsar J1638-4725 is in an eccentric (e ~ 0.94) orbit with a
5.3-yr period about a ~ 20 solar mass optically-identified companion.
The pulsar is undetectable in the radio for ~ 1 yr around periastron,
most likely due to absorption and scattering by the dense stellar
environment. During this radio-quiet phase, X-rays from the "propeller
regime" accretion of matter onto the NS magnetosphere are likely to be
detectable. If such emission is detected near periastron (April 30
2005), this binary will be the first system in which an accretion phase
alternates with a radio pulsar phase, providing a link between the
populations of X-ray transients and radio pulsars and an important
diagnostic of the companion star mass loss rate and its terminal
velocity (and hence mass and radius). X-rays may also be detected from
the pulsar, the companion star, and pulsar wind/disk shock but are
expected to be an order of magnitude less than that expected from
propeller accretion.

Sequence Number: 400467

Title : The nature of the gamma-ray source HESS J1826-148
PI: Funk
Abstract: We (the HESS collaboration) used the first year of operation of the
HESS TeV array to conduct a survey of the inner galaxy. More than a
dozen new and unidentified sources have been discovered (Aharonian et
al., Science, in press). Only one of them, HESS J1826-148, is not
extended and was found to be variable, and should be associated with a
compact object. The TeV source is close to microquasar LS5039, but the
nominal separation of 50" is compatible with a spatial association on a
9% basis only. Simultaneous XTE-ASM measurements during TeV
observations were uncorrelated. It is plausible that HESS J1826-148 is
actually not coincident with LS5039, but with another compact, possibly
long-lived transient source, which would in any case be the first
example of a new class of TeV emitting sources. We propose DDT for 8
epochs of simultaneous Chandra & HESS observations to search for a
spatially coincident, hard X-ray source with correlated variability
patterns to enable unambiguous ident.

Sequence Number: 400447

Title : Following the decay of the new accretion powered msec pulsar IGR
J00291+5934
PI: Jonker
Abstract: The proposed DDT observations have three goals: 1) As this transient
decays, its magnetic field should become dynamically important. We will
compare the shape of the lightcurve and the spectral information with
that of a NS SXT for which no pulsations have been found. The strength
of the magnetic field is an important unknown quantity for evolutionary
link between LMXBs and msec radio pulsars. 2) A comparison of the
evolution of the SED of this NS SXT with similar data on black hole
(BH) SXTs will constrain the differences in jet power between NSs and
BHs. 3) A comparison of the spectrum and the luminosity of the source
in quiescence immediately after the outburst with that during an
observation in AO7 would allow us to assess the neutron star cooling
after an outburst. Those findings can be compared with those of the
transients XTE J1709-267 and MXB 1658-29 (Jonker et al. 2003/4;
Wijnands et al. 2004).

Sequence Number: 400446

Title : Following the decay of the new accretion powered msec pulsar IGR
J00291+5934
PI: Jonker
Abstract: The proposed DDT observations have three goals: 1) As this transient
decays, its magnetic field should become dynamically important. We will
compare the shape of the lightcurve and the spectral information with
that of a NS SXT for which no pulsations have been found. The strength
of the magnetic field is an important unknown quantity for evolutionary
link between LMXBs and msec radio pulsars. 2) A comparison of the
evolution of the SED of this NS SXT with similar data on black hole
(BH) SXTs will constrain the differences in jet power between NSs and
BHs. 3) A comparison of the spectrum and the luminosity of the source
in quiescence immediately after the outburst with that during an
observation in AO7 would allow us to assess the neutron star cooling
after an outburst. Those findings can be compared with those of the
transients XTE J1709-267 and MXB 1658-29 (Jonker et al. 2003/4;
Wijnands et al. 2004).

Sequence Number: 400445

Title : Following the decay of the new accretion powered msec pulsar IGR
J00291+5934
PI: Jonker
Abstract: The proposed DDT observations have three goals: 1) As this transient
decays, its magnetic field should become dynamically important. We will
compare the shape of the lightcurve and the spectral information with
that of a NS SXT for which no pulsations have been found. The strength
of the magnetic field is an important unknown quantity for evolutionary
link between LMXBs and msec radio pulsars. 2) A comparison of the
evolution of the SED of this NS SXT with similar data on black hole
(BH) SXTs will constrain the differences in jet power between NSs and
BHs. 3) A comparison of the spectrum and the luminosity of the source
in quiescence immediately after the outburst with that during an
observation in AO7 would allow us to assess the neutron star cooling
after an outburst. Those findings can be compared with those of the
transients XTE J1709-267 and MXB 1658-29 (Jonker et al. 2003/4;
Wijnands et al. 2004).

Sequence Number: 300171

Title : HETGS Observation of a Transient Hard X-ray Symbiotic Binary
PI: Sokoloski
Abstract: RT Cru is one of a subset of particularly active symbiotic stars (SS;
white dwarfs accreting from the wind of red giants) characterized by
rapid optical flickering, and in some cases jets and recurrent nova
explosions. The recent detection of RT Cru with INTEGRAL (ATels 519,
528, and 591) indicates that during outburst, it also produces the
hardest X-ray emission of any known SS. In August, RT Cru was observed
with the Swift XRT for 4.7 ks. The XRT observation revealed several
emission-line complexes, a possible broad soft component, and hints of
continuum emission. The line blends could be due to Si, Ca, and Ar. But
Ca and Ar are not strong in nova spectra, and large blue- or red-shifts
are not expected in RT Cru. We request a 50-ks HETGS observation to
resolve and identify the emission lines and any absorption features,
and to isolate the continuum. We will also search for extended jet
structure in the 0th-order spot. This observation should produce ~2000
counts in the MEG.

Sequence Number: 200372

Title : HRC Imaging of the `Fainted' Primary of the Alpha Centauri System
PI: Ayres
Abstract: The famous Alpha Centauri binary (G2V+K1V) has been regularly observed
in X-rays since first resolved by Einstein 25 years ago, later by
ROSAT/HRI, and more recently by XMM. The latest EPIC-pn imaging
uncovered an extremely odd result: solar twin Alp Cen A has nearly
disappeared in X-rays. This behavior had not been encountered in the
previous quarter century of X-ray work on the system, and is quite
unlike anything ever seen on the Sun, except perhaps the curious
18th-century "Maunder minimum," when sunspots vanished from the solar
disk for decades at a time, and coronal activity likely was severely
depressed; although, of course, we don't have any X-ray observations
from then to confirm the true coronal behavior. The AB orbit now has
closed below the resolution of EPIC, although still is easy for Chandra
to separate. I therefore propose to continue the crucial X-ray time
series on this important solar analog using Chandra's HRC-I.

Sequence Number: 200371

Title : HRC Imaging of the `Fainted' Primary of the Alpha Centauri System
PI: Ayres
Abstract: The famous Alpha Centauri binary (G2V+K1V) has been regularly observed
in X-rays since first resolved by Einstein 25 years ago, later by
ROSAT/HRI, and more recently by XMM. The latest EPIC-pn imaging
uncovered an extremely odd result: solar twin Alp Cen A has nearly
disappeared in X-rays. This behavior had not been encountered in the
previous quarter century of X-ray work on the system, and is quite
unlike anything ever seen on the Sun, except perhaps the curious
18th-century "Maunder minimum," when sunspots vanished from the solar
disk for decades at a time, and coronal activity likely was severely
depressed; although, of course, we don't have any X-ray observations
from then to confirm the true coronal behavior. The AB orbit now has
closed below the resolution of EPIC, although still is easy for Chandra
to separate. I therefore propose to continue the crucial X-ray time
series on this important solar analog using Chandra's HRC-I.

Sequence Number: 200370

Title : HRC Imaging of the `Fainted' Primary of the Alpha Centauri System
PI: Ayres
Abstract: The famous Alpha Centauri binary (G2V+K1V) has been regularly observed
in X-rays since first resolved by Einstein 25 years ago, later by
ROSAT/HRI, and more recently by XMM. The latest EPIC-pn imaging
uncovered an extremely odd result: solar twin Alp Cen A has nearly
disappeared in X-rays. This behavior had not been encountered in the
previous quarter century of X-ray work on the system, and is quite
unlike anything ever seen on the Sun, except perhaps the curious
18th-century "Maunder minimum," when sunspots vanished from the solar
disk for decades at a time, and coronal activity likely was severely
depressed; although, of course, we don't have any X-ray observations
from then to confirm the true coronal behavior. The AB orbit now has
closed below the resolution of EPIC, although still is easy for Chandra
to separate. I therefore propose to continue the crucial X-ray time
series on this important solar analog using Chandra's HRC-I.

Sequence Number: 200363

Title : Monitoring the X-ray Emission of the Newly Erupted EXor-type V1118 Ori
PI: Audard
Abstract: The origin of the X-ray emission in young, accreting stars remains a
mystery. Accretion seems the dominant mechanism in TW Hya (cool plasma;
high densities). However, other moderately accreting classical T Tauri
stars show high temperatures and low densities. Eruptive young stars
(FUors and EXors) are the key to understanding the importance of
accretion for X-rays since they suddenly display increased accretion
rates from 1E-7 to 1E-4 Msol/year. FUors display brighter and longer
outbursts than EXors but they are far less frequent. Recently, the
(FUor-type) V1647 Ori erupted and triggered an international
observation campaign. In X-rays, Kastner et al. (2004) reported a
30-fold flux increase from the pre-outburst flux, indicating that the
high-energy emission in young stars can increase dramatically due to
the rapid increase of accretion rates in FUor/EXor outbursts. However,
the flux rapidly dropped in the steady high state.

Sequence Number: 800560

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800559

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800558

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800557

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800557

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800556

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800555

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800555

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800554

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800553

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800552

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800551

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800550

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 800549

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra data
alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.

Sequence Number: 701014

Title : Multiwavelength Reverberation Mapping of NGC 4395, the Least Luminous
Seyfert 1 Galaxy
PI: Moran
Abstract: NGC 4395 is the least luminous Seyfert 1 galaxy known, and one of the
most X-ray variable. Its extremely small BH mass implies light-crossing
timescales 100-1000 times shorter than in luminous AGN. A
multiwavelength reverberation mapping campaign on this object spanning
the UV (HST), optical (KPNO 4m & Lick 3m), and IR (KPNO 2.1m & IRTF 3m)
has been approved for two 8-hr periods in April 2004. We propose to use
this unique opportunity to conduct simultaneous monitoring (2 x 30ks)
with Chandra. A previous Chandra observation revealed extremely rapid,
large-amplitude variability and dramatic long-term spectral
variability. Our program will allow us to compare for the first time
the X-ray variability in an AGN of this luminosity to the UV/optical/IR
continuum and emission-line variability. Apart from indicating the
state of the ionizing source during the reverberation campaign, the
Chandra data can shed new light on the accretion and emission processes
in this enigmatic AGN.

Sequence Number: 701013

Title : Multiwavelength Reverberation Mapping of NGC 4395, the Least Luminous
Seyfert 1 Galaxy
PI: Moran
Abstract: NGC 4395 is the least luminous Seyfert 1 galaxy known, and one of the
most X-ray variable. Its extremely small BH mass implies light-crossing
timescales 100-1000 times shorter than in luminous AGN. A
multiwavelength reverberation mapping campaign on this object spanning
the UV (HST), optical (KPNO 4m & Lick 3m), and IR (KPNO 2.1m & IRTF 3m)
has been approved for two 8-hr periods in April 2004. We propose to use
this unique opportunity to conduct simultaneous monitoring (2 x 30ks)
with Chandra. A previous Chandra observation revealed extremely rapid,
large-amplitude variability and dramatic long-term spectral
variability. Our program will allow us to compare for the first time
the X-ray variability in an AGN of this luminosity to the UV/optical/IR
continuum and emission-line variability. Apart from indicating the
state of the ionizing source during the reverberation campaign, the
Chandra data can shed new light on the accretion and emission processes
in this enigmatic AGN.

Sequence Number: 600412

Title : Monitoring a New X-ray Transient 2.5 Arcseconds South of Sgr A*
PI: Baganoff
Abstract: Chandra observations on 5-6 July reveal a transient 2.5" south (0.1 pc
at 8 kpc) of Sgr A*, in an extreme habitat already known to contain two
dense star clusters and a 3e6 solar-mass black hole. Its 2-8 keV
spectrum (gamma < 0.25) is harder than most INTEGRAL sources. Its
luminosity is >2e34 erg/s, with a possible 4 h period, so it is an
accreting BH or NS, and may emit much of its flux above 10 keV. Thus,
this source may be responsible for much of the emission detected by
INTEGRAL and HESS (TeV) during recent observations of Sgr A*. Also,
diffuse X-rays only 4 light-months from the source have brightened,
suggesting the presence of a jet. We propose to observe the progression
of this outburst: (1) to tell us whether it is active during upcoming
gamma-ray observations, (2) to determine the mechanism that feeds the
source (disk or wind), and (3) to observe the evolution of the jet.
This is a singular opportunity to study the interplay between
accretion, jets, and gamma-ray emission.

Sequence Number: 500600

Title : X-ray observation of a unique radio transient near the Galactic Center
PI: Hyman
Abstract: We have detected a new unresolved radio transient using the VLA at 330
MHz (Hyman et al. Nature, submitted) which exhibited 10 min flares to 1
Jy at regular 1.25 hr intervals during a 7-hr observation starting on
2002-09-30. If the source is near the Galactic Center the implied
brightness temperature is several orders of magnitude too high to be
incoherent synchrotron, implying that this is a new class of coherent
emitter. No X-ray emission was seen above 15 mcrab using RXTE bulge
scanning data from the previous and following day, but the field has
never been observed by Chandra or XMM. We propose a 10 ks observation
to search for flaring or quiescent X-ray emission from this source. If
a detection is made this will (1) improve the position of the source
from 10" to <1", (2) constrain source models based on the X-ray flux
and spectrum, and (3) constrain the distance using n_H. If the source
is undetected we will still improve constraints on L_x/L_r by several
orders of magnitude.

Sequence Number: 500591

Title : GRB040912: An Unusual Event Exhibiting Strong Spectral Evolution from a
GRB to an XRF
PI: Ricker
Abstract: The WXM on HETE has localized a GRB event that exhibits highly unusual
spectral evolution. Initially, the emission is hard for 10-20 seconds,
evolving to an XRF over the next 200 seconds. No other event like this
has been detected in the 4 years of HETE operations. The spectral
signature is possibly indicative of a very high redshift event. An
prompt, accurate localization of the X-ray afterglow, the spectrum, and
its decay index by Chandra is requested.

Sequence Number: 500590

Title : GRB040912: An Unusual Event Exhibiting Strong Spectral Evolution from a
GRB to an XRF
PI: Ricker
Abstract: The WXM on HETE has localized a GRB event that exhibits highly unusual
spectral evolution. Initially, the emission is hard for 10-20 seconds,
evolving to an XRF over the next 200 seconds. No other event like this
has been detected in the 4 years of HETE operations. The spectral
signature is possibly indicative of a very high redshift event. An
prompt, accurate localization of the X-ray afterglow, the spectrum, and
its decay index by Chandra is requested.

Sequence Number: 500585

Title : Search for the Counterpart of a New TeV Gamma-ray Source in the
Galactic Plane
PI: Halpern
Abstract: We propose to examine the error box of the second unidentified TeV
gamma-ray source. The IACT array H.E.S.S. has discovered a source in
the 0.6-10 TeV range, designated VHE J1303-63. It is 0.65 deg north of
the famous Be/X-ray pulsar PSR B1259-63, which was also detected. But
the new source is even brighter than the pulsar, about 0.1 Crab, and
its statistical significance is at least 13 sigma (Beilicke, et al.
2004 Heidelberg Gamma-Ray Meeting, and Beilicke, Aharonian,
Heinzelmann, Hofmann, Wagner, private comm.) The error box of VHE
J1303-63 was covered only by a ROSAT observation, which does not show
any counterpart within the error circle. Since this source is in the
Galactic plane (as is the first unidentified TeV source J2032+4130), it
is likely that its X-ray counterpart is highly absorbed. In a Chandra
DDT observation of TeV J2032+4130, we found a possible hard X-ray
counterpart (Mukherjee et al. 2003, ApJ, 589, 487). We propose a
similar search for VHE J1303-63.

Sequence Number: 500508

Title : Observations of an extremely X-ray rich GRB detected by Integral
PI: Kouveliotou
Abstract: Integral has observed an extremely X-ray rich GRB, the richest seen in
3-40 keV. The event was detected with IBIS; it was also the first ever
seen in the Jem-X FOV. The IBIS spectrum is very soft, with a spectral
index of 2.5 and a flux of 1.4e-8 erg/cm^2 s (15-40 keV). It becomes
very faint after 40 keV and is not detectable above 100 keV. The Jem-X
peak flux (3-20 keV) is 0.5 Crab (~1.4 e-8 erg/cm^2 s); most of this
flux comes below 10 keV! This event is thus a prime example of an XRR
GRB, which may be either a classical GRB seen off axis, or a yet
different class considered to be intrinsically subenergetic GRBs. There
are 3 such bursts observed to date, all associated with SNe. We have
approved ESO observations; these, along with information of the source
position, energetics, and spectrum, as early as possible, would be
crucial in understanding the nature of XRR GRBs and may open a new
window in the field, by probing their early properties with the superb
CXO capabilities.

Sequence Number: 500507

Title : Observations of an extremely X-ray rich GRB detected by Integral
PI: Kouveliotou
Abstract: Integral has observed an extremely X-ray rich GRB, the richest seen in
3-40 keV. The event was detected with IBIS; it was also the first ever
seen in the Jem-X FOV. The IBIS spectrum is very soft, with a spectral
index of 2.5 and a flux of 1.4e-8 erg/cm^2 s (15-40 keV). It becomes
very faint after 40 keV and is not detectable above 100 keV. The Jem-X
peak flux (3-20 keV) is 0.5 Crab (~1.4 e-8 erg/cm^2 s); most of this
flux comes below 10 keV! This event is thus a prime example of an XRR
GRB, which may be either a classical GRB seen off axis, or a yet
different class considered to be intrinsically subenergetic GRBs. There
are 3 such bursts observed to date, all associated with SNe. We have
approved ESO observations; these, along with information of the source
position, energetics, and spectrum, as early as possible, would be
crucial in understanding the nature of XRR GRBs and may open a new
window in the field, by probing their early properties with the superb
CXO capabilities.

Sequence Number: 500506

Title : Is GRB 031203 a GRB-SN seen off axis?
PI: Kouveliotou
Abstract: Recent results indicate that there is a common convergence of several
classes of transient phenomena (GRBs, GRB 980425/SN 1998bw, XRFs, and
the most energetic SNe), to a common luminosity ~10^39-10^40 erg/s
about 3-10 years after the explosive event. A simple theoretical
interpretation favors a continuum of events in which the early
luminosity is sensitive to the angle at which the event is observed.
GRB031203 may well be the first of these `gap' events if its X-ray
luminosity can be attributed to its having been viewed substantially
off-axis. Further, if its reported redshift of z=0.105 is confirmed,
GRB031203 is the closest GRB after GRB980425 and thus, an excellent
candidate for a SN to be found in its lightcurve. Indeed, recent
observations (GCN 2544) indicate that this may be the case. Our
suggested 75 ks observation of GRB031203 will provide a luminosity
limit of ~5.5x10^(40) erg/s, comparable to the luminosity seen in SN
1998bw after a few hundred days.

Sequence Number: 500505

Title : Prompt Observation of the Type Ib/c Supernova 2001em
PI: Pooley
Abstract: The X-ray emission from core-collapse SNe comes from the interaction of
the ejected matter and the circumstellar material, which is the
progenitor's pre-SN wind. It is thus a unique probe of both the ejected
material and the SN environment. We propose a 30 ksec Chandra obs. of
the type Ib/c SN 2001em (which just turned on in the radio; K. Weiler,
IAUC submitted) to determine the X-ray flux to ~5% (see below for flux
estimate) and temperature to ~10%. This information, combined with
continued VLA obs., will determine the mass-loss rate of the
progenitor, thus providing information about both the explosion
environment and the nature of the progenitor. This is especially
important in the case of SNe Ib/c given the association with some GRBs.
Such information will provide a key piece of the puzzle in
understanding the progenitor systems of SNe Ib/c (and by association,
GRBs) and the aftermath of the SN (and GRB) explosion.

Sequence Number: 500504

Title : Monitoring the spectral evolution of RXJ0720-3125 and determining its
nature.
PI: Vink
Abstract: RXJ0720-3125 is a protypical isolated neutron star with a
blackbody-like spectrum. However, we've recently found with
XMM-Newton's RGS that between 5-2000 and 10-2003 its spectrum has
changed. Until 5-2003 this change was slow, but since then the changes
have been dramatic, and the spectrum is now quite distinct from a BB;
it has increased its emission > 0.5 keV & decreased it < 0.5 keV (de
Vries et al. 2004, astro-ph/0401028). We would like to observe this
source with the LETGS in order to see whether the hardening has
continued, is slowly reversing, or whether it is back to its BB-like
state. Moreover, if the source is still in a hard state we need the
LETGS so check whether the absorption < 0.5 keV is Gaussian, in which
case it might be due to proton-cyclotron absorption. NB the deviations
from a BB may relevant to the whole class of isolated NSs, as all of
them may have similar but less obvious deviations from a BB spectrum.

Sequence Number: 500503

Title : GRB 031203: A Possible Analogue to GRB980425/SN1998bw
PI: Kulkarni
Abstract: GRB03120, a seemingly typical burst was localized to a 5-arcmin region
by Integral. XMM found a source with initial flux of 3E-13 erg/cm2/s
which faded as t^{-0.4} during t=0.25 to 6 days. Separately, we
detected a slowly fading radio counterpart. The X-ray/radio source is
coincident with a bright, z=0.105 galaxy. Relative to other afterglows,
the fading of the radio/X-ray is unusually slow. Furthermore, the 1E+43
erg/s X-ray luminosity and the 1E+29 erg/s/Hz radio luminosity are 10 -
1000 times less than for typical afterglows, yet comparable to those
observed for GRB980425/SN1998bw. Most curiously, there is no optical
afterglow or hint of an underlying supernova. Keck host spectrum rules
out an AGN origin for the X-ray source. We conclude that GRB 031203 is
a new type of cosmic explosion with some parallels. As argued below,
our continued VLA campaign complemented by the proposed Chandra
observations offer us the best chance to decipher the nature of this
mysterious source.

Sequence Number: 400376

Title : A Search for X-Ray Emission from the Double-Pulsar Binary System
J0737-3039
PI: McLaughlin
Abstract: We have discovered the first double neutron star binary, J0737-3039, in
which both stars are observable radio pulsars. The spin periods of the
recycled pulsar, A, and its companion, B, are 22 ms and 2.7 s. The
stars are separated by only 2.9 light seconds in a 2.4-hr orbit. At a
distance of only 500 pc, this system promises to be the best ever
laboratory for relativistic astrophysics. Observations of B show its
flux to vary greatly, making it only detectable for two brief periods
when it is in front of A. This variation is likely due to the
interaction of A's spin-down luminosity, in the form of a relativistic
wind and Poynting flux, with B's magnetosphere. We also see a brief (22
sec) eclipse of A as it passes behind B. A detection of non-thermal
X-rays from A will provide, for the first time, a probe of the
magnetosphere and local environment of a neutron star. We may also
detect thermal X-rays from B or X-rays from the shock interactions of
this extremely relativistic system.

Sequence Number: 300145

Title : Outburst in Mira AB?
PI: Karovska
Abstract: The nearby system Mira AB composed of an aging AGB star (Mira A) and a
WD companion (Mira B) offers a unique laboratory for studying wind
accretion processes, a poorly understood phenomenon in many sources.
Recent Chandra ACIS-S Obs.(70ks on 12/6/03; PI.M.Karovska) resolved for
the first time the components (~0.6") in X-rays, and detected a new
bright soft source (< 0.7 keV) in addition to the harder (1-4 keV)
emission from Mira B. The new source is spatially and spectrally
separated from Mira B and likely associated with Mira A. This is the
first detection of X-rays from an AGB star. This source was not
detected by ROSAT in 1993 or recently by XMM 8/03 (AAS/03,J.Kastner),
and could be a transient phenomenon. Model fitting shows that the soft
X-ray emission is likely several emission lines, rather then a
continuum; with ACIS spectral resolution we cannot resolve or identify
these lines. We propose a 40ks LETG+HRC-S obs. to identify the lines
and determine the emission mechanism.

Sequence Number: 300144

Title : A HRC-S LETG Observation of V4743 Sgr
PI: Starrfield
Abstract: We have observed V4743 Sgr three times with CHANDRA (March, July, and
September 2003) with our last cycle ToO program but are now out of
time. We are requesting an additional observation to follow its
evolution back to minimum. Our first observation found a large
amplitude oscillation with a period of ~1300 s (see Sept 2003 ApJ
Letters). Our Xray observations showed that the oscillations were multi
periodic, and that the principal period is increasing. These results
suggest that we are observing non-radial modes and that the surface
characteristics of the WD are evolving on a few month time scale. We
are analyzing the spectra and find that the white dwarf temperature at
the first grating observation was about 600,000K. We are seeing the WD
cool slightly with time. The light curve and spectral variations are
very exciting and we would like to follow the evolution as long as
there is nuclear burning on the white dwarf.

Sequence Number: 200298

Title : A Star is Born: X-ray Imaging of the Onset of an FU Ori Outburst
PI: Kastner
Abstract: The highest accretion rates among low-mass stars are associated with
the FU Ori (FUor) phase. This phase is marked by ~100-yr-long outbursts
during which a star brightens by 5-15 magnitudes and its mass accretion
rate likely increases by up to a factor of 10^4. The 'standard model'
for the formation of Sunlike stars is that they go through one or more
FUor epochs during their pre-main sequence evolution, and that this
phase(s) is when such stars gain most of their mass. We propose to
observe a newly identified FUor during the rarely observed rise phase
of its outburst. This almost certainly will be the only chance for CXO
to make observations of this evolutionary phase. These observations
will be essential in understanding and improving models for the
formation of all low mass stars, and to inform the ongoing debate
concerning the origin of X-rays from young, low-mass stars (e.g.
Kastner et al 2002, ApJ 567, 434).

Sequence Number: 200297

Title : A Star is Born: X-ray Imaging of the Onset of an FU Ori Outburst
PI: Kastner
Abstract: The highest accretion rates among low-mass stars are associated with
the FU Ori (FUor) phase. This phase is marked by ~100-yr-long outbursts
during which a star brightens by 5-15 magnitudes and its mass accretion
rate likely increases by up to a factor of 10^4. The 'standard model'
for the formation of Sunlike stars is that they go through one or more
FUor epochs during their pre-main sequence evolution, and that this
phase(s) is when such stars gain most of their mass. We propose to
observe a newly identified FUor during the rarely observed rise phase
of its outburst. This almost certainly will be the only chance for CXO
to make observations of this evolutionary phase. These observations
will be essential in understanding and improving models for the
formation of all low mass stars, and to inform the ongoing debate
concerning the origin of X-rays from young, low-mass stars (e.g.
Kastner et al 2002, ApJ 567, 434).

Sequence Number: 100053

Title : Chandra Snapshot Spectral Imaging of Comets C/2001 Q4 (NEAT) and C/2002
T7 (LINEAR)
PI: Lisse
Abstract: The highly favorable perigee passage of the very bright comets C/2001
Q4 (NEAT) and C/2002 T7 (LINEAR) in late May 2004 provides an
opportunity to study cometary x-ray emission in conjunction with the
new CHIPS spectroscopic mission. In 10 ksec of on-target time for each
comet, ACIS-S will obtain snapshot images of the comets in the heart of
the CHIPS 0.05 0.150 keV spectroscopic monitoring period in late-May
2004. The combined observations have the potential of directly
detecting for the first time the ultra-soft emission due to Mg, S, Si,
and Fe predicted by McCammon et al. (2002) from soft x-ray background
measurements and by Kharchenko et al. (2000, 2003) from models of solar
wind minor ion charge exchange emission. New work by Wegmann, Dennerl,
and Lisse (2004) allows a determination of the neutral gas production
rate from the spatial scale of the emission, and an independent
determination of the solar wind minor ion flux density using the x-ray
surface brightness.

Sequence Number: 100053

Title : Chandra Snapshot Spectral Imaging of Comets C/2001 Q4 (NEAT) and C/2002
T7 (LINEAR)
PI: Lisse
Abstract: The highly favorable perigee passage of the very bright comets C/2001
Q4 (NEAT) and C/2002 T7 (LINEAR) in late May 2004 provides an
opportunity to study cometary x-ray emission in conjunction with the
new CHIPS spectroscopic mission. In 10 ksec of on-target time for each
comet, ACIS-S will obtain snapshot images of the comets in the heart of
the CHIPS 0.05 0.150 keV spectroscopic monitoring period in late-May
2004. The combined observations have the potential of directly
detecting for the first time the ultra-soft emission due to Mg, S, Si,
and Fe predicted by McCammon et al. (2002) from soft x-ray background
measurements and by Kharchenko et al. (2000, 2003) from models of solar
wind minor ion charge exchange emission. New work by Wegmann, Dennerl,
and Lisse (2004) allows a determination of the neutral gas production
rate from the spatial scale of the emission, and an independent
determination of the solar wind minor ion flux density using the x-ray
surface brightness.

Sequence Number: 100053

Title : Chandra Snapshot Spectral Imaging of Comets C/2001 Q4 (NEAT) and C/2002
T7 (LINEAR)
PI: Lisse
Abstract: The highly favorable perigee passage of the very bright comets C/2001
Q4 (NEAT) and C/2002 T7 (LINEAR) in late May 2004 provides an
opportunity to study cometary x-ray emission in conjunction with the
new CHIPS spectroscopic mission. In 10 ksec of on-target time for each
comet, ACIS-S will obtain snapshot images of the comets in the heart of
the CHIPS 0.05 0.150 keV spectroscopic monitoring period in late-May
2004. The combined observations have the potential of directly
detecting for the first time the ultra-soft emission due to Mg, S, Si,
and Fe predicted by McCammon et al. (2002) from soft x-ray background
measurements and by Kharchenko et al. (2000, 2003) from models of solar
wind minor ion charge exchange emission. New work by Wegmann, Dennerl,
and Lisse (2004) allows a determination of the neutral gas production
rate from the spatial scale of the emission, and an independent
determination of the solar wind minor ion flux density using the x-ray
surface brightness.

Sequence Number: 800375

Title : A Chandra Survey of a uniformly-selected sample of high-redshift galaxy
clusters.
PI: Bautz
Abstract: This request is being submitted after consulation with the CXC Director
to compensate for unusually high background during, and premature
termination by SCS 107 of obsid 3577 (seq 800298.) This is a routine
(non-time-critical) request. The high background and early termination
substantially reduced the signal:noise ratio of this extended,
high-redshift cluster.

Sequence Number: 500500

Title : Understanding the nature of the unidentified EGRET source 3EG
J1631-4033
PI: Foschini
Abstract: The EGRET unidentified sources represent one of the most challenging
enterprises of the modern astrophysics. In the 3rd EGRET catalog there
are 271 sources, 170 of them are still unidentified. The identified
sources are mainly blazars (93) and pulsars (5). Now that the most
probable sources are identified, it remains to understand if there are
other populations of objects able to generate high energy (E>100 MeV)
gamma-rays, or if there are different engines powering known objects,
like - for example - transition objects between FRI radio galaxies and
BL Lac or off-beam gamma-ray pulsars of the Gould belt. Given the
high-energy gamma-ray (EGRET) and the hard-X (ISGRI) spectral and
temporal characteristics, this source could be the first example of
off-beam gamma-ray pulsars of the Gould Belt, predicted by several
authors like I. Grenier, N. Gehrels, A. Harding, et al.

Sequence Number: 500499

Title : SN 2003jd; A GRB-like hypernova
PI: Watson
Abstract: SN 2003jd has been identified as a peculiar Type Ic (Stanek et al. GCN
2431) showing strong similarities with SN 1998bw near maximum. However
the spectrum does not match well with other peculiar type Ic's like SN
1997ef or 2002ap. There is an association between GRBs and hypernovae
(HNe), (1998bw/980425 & 2003dh/030329) and it has been suggested that
HNe are GRBs observed off-axis and that HNe-without-GRBs may have early
X-ray emission identifiable with non-thermal afterglow-like emission.
SN 2003jd is an excellent candidate, the best to date, for a GRB-like
HN without an observed GRB and represents an opportunity to examine the
characteristics of a GRB-less HN where the HN appears to be very
similar to those observed in GRBs. The paucity of X-ray data on HNe &
this HN's similarity to a GRB, prompts us to request an initial imaging
observation with Chandra (with a possible follow-up observation after 1
month), to determine the X-ray luminosity and the behaviour of the
lightcurve.

Sequence Number: 500498

Title : Unveiling the multiwavelength spectrum of the AXP XTEJ1810-197
PI: Israel
Abstract: XTEJ1810-197 is a newly discovered Anomalous X-ray Pulsar (AXP), first
detected by XTE and INTEGRAL and then observed by Chandra (DDT obs.
carried out on 28 August 2003) and XMM (ToO obs.; see Gotthelf et al.
2003, astro-ph/0309745). XTEJ1810-197 is also the first confirmed
example of a transient AXP. The Chandra data allowed to detect
XTEJ1810-197, about 15' off-axis, resulting in a less accurate position
(radius of about 2.5"; 1sigma). On October 7th we carried out deep IR
obs. with the adaptive optic instrument (NACO) mounted on the VLT.
These data allowed us to sort out four faint (Ks>19.5) IR counterpart
candidates to XTEJ1810-197. The latters are separated each other of
more than 1" (within the Chandra uncertainty region of radius 2.5").
Therefore, the requested Chandra on-axis obs. will allow us to
unambiguously identify the counterpart to XTEJ1810-197 (position with
radius of about 0.6" at 90% c.l.).

Sequence Number: 500415

Title : Locating the Transient AXP XTE J1810-197
PI: Gotthelf
Abstract: The newly discovered 5.5s X-ray pulsar XTE J1810-197 (Markwardt et al,
AUC 8168) is the 2nd example of a transient AXP (TAXP). Unlike the
original TAXP, AX J1845-058 (Gotthelf & Vasisht 1998, NA, 3, 293), this
new source was found prior to its fading away; furthermore, an archival
XTE detection provides a spin-down rate, confirming its AXP status.
TAXPs may be related to a growing class of young, isolated NSs whose
properties are distinct from young rotation-powered pulsars, and whose
basic physics is unknown. Examples are, the central compact object
(CCO) in SNR RCW 103, whose flux is variable over years and lack
pulsations, the Cas A point source, another possible quiescent AXP,
based on its spectrum and central SNR location, and the original TAXP,
AX J1845-058, found to be associated with a SNR. Chandra provides a
unique opportunity to characterize a fading AXP, and to determine an
possibly evolutionary link with the CCOs, thus unifying these
mysterious manifestations of NSs.

Sequence Number: 500413

Title : SN2002ic and its Circumstellar Medium
PI: Hughes
Abstract: Supernova (SN) 2002ic (IAUC 8019) is the first thermonuclear or Type Ia
SN ever to show hydrogen in its spectrum (IAUC 8151). Hamuy et al
(astro-ph/0306270) argue that the H alpha emission of the SN arises
from a dense circumstellar medium (CSM), which itself was the result of
pre-SN mass loss from a massive asymptotic giant branch star that was
the companion to the white dwarf that exploded as the SN. This result
could have wide implications for the origin of SNe Ia and their
cosmological use. This study is based on observations taken between
November and February; our more recent VLT data from July continue to
show strong H alpha emission. Radio emission has not been detected
(IAUC 8157), which can be explained if there is substantial free-free
absorption in the CSM gas. Hard X-ray observations are the most
sensitive probe of the CSM surrounding SN Ia; here we propose X-ray
observations of SN2002ic to detect the shocked CSM and confirm the high
mass loss rate of the progenitor.

Sequence Number: 500412

Title : ToO observations of SGR 1806-20 in an active state
PI: Woods
Abstract: SGRs are a class of high-energy transients that emit brief, intense
bursts of soft gamma-rays. There is now strong evidence in support of
the idea that SGRs (and AXPs) are magnetars. SGR 1900+14, SGR 1627-41
and the AXP 1E 2259+586 have shown that during epochs of intense burst
activity, there are changes in the persistent and pulsed emission
properties of the underlying X-ray source. Quantifying these changes
has shed light on the burst mechanism and the consequences of bursts in
magnetars. Details are given in the AO-4 and AO-5 proposals by Woods et
al. SGR 1806-20 recently entered a new phase of activity. As yet there
have been no detections of changes in the persistent emission of this
source during periods of burst activity. The transient effects of burst
activity seen in SGR 1900+14, SGR 1627-41 and 1E 2259+586 are markedly
different. Given the low number of magnetars, it is important to study
these transient effects whenever possible to better understand their
nature.

Sequence Number: 500411

Title : Chandra LETG/ACIS Observation of H2650 (=GRB030328)
PI: Ricker
Abstract: GRB030328 is a very bright, long GRB localized to arcminute accuracy by
the HETE SXC in real time at 1120 UT. An observation commencing in less
than 20 hours may permit the detection of Si and S lines (Butler et al
2003) at a high level of significance.

Sequence Number: 500410

Title : GRB030226: TESTING THE DUST DESTRUCTION HYPOTHESIS
PI: Pedersen
Abstract: GRB030226 was discovered by HETE-2 and an optical transient identified
2.6h later. The redshift has now been measured to z=1.99 placing it in
an ideal redshift window for combined X-ray and lyman alpha studies: It
is close enough for X-ray absorption in the vicinity of the burst to be
measurable in the CXO spectrum and far enough that lyman alpha can be
reached from the ground. Combining the two measurements with
optical/NIR observations we can accurately determine the amount of
oxygen and iron (dominating the X-ray absorption), the amount of
neutral hydrogen, and the dust content in the GRB environment. For this
burst, we can thus tell if the low dust content, found in most burst
environments, is due to either a) low metallicity and a universal
dust-to-metals ratio, or b) solar metallicity, but a low dust-to-metal
ratio. In case b) most of the metals are in the gas phase - indicating
significant dust destruction.

Sequence Number: 500409

Title : EXPLORING THE GRB-SUPERNOVA CONNECTION VIA SN2003L
PI: Kulkarni
Abstract: The type Ibc SN 1998bw provides a link between GRBs and supernovae.
Like GRBs, it had relativistic ejecta (as inferred from the brilliant
radio emission and early non-thermal X-ray emission) but with lower
Lorentz factor. Ordinary SNe do not show bright radio emission at early
times and theoretically appear unable to produce significant
relativistic ejecta. Thus it is generally assumed that SN 1998bw
harbored a central engine. For the past four years, we have been
searching for other such engine-driven SNe and have recently reported
bright emission from the type Ic SN2003L. With a radio luminosity that
is currently 1.9E+28 erg/s/Hz (15% of SN1998bw at peak) and rising,
this event is very similar to SN1998bw. A detection of non-thermal
X-ray emission (synchrotron or inverse-Compton) would confirm the
inference of relativistic ejecta and mark SN 2003L as another link
between GRBs and SNe. A 30 ks observation will allow a rough
determination of the spectrum.

Sequence Number: 400324

Title : Localization and Spectroscopy of the Millisecond X-Ray Pulsar XTE
J1814-338
PI: Chakrabarty
Abstract: A new msec X-ray pulsar (MSXP) , XTE J1814-338 (P=3.2 ms, Porb=1.9 hr)
was just discovered (Markwardt, IAUC submitted). Its orb params are
very similar to those of pulsar SAX J1808.4-3658, the only XRB known
with a brown dwarf donor. J1808 also the only one of 4 prev known MSXPs
whose orb params and disk geometry led to a bright opt counterpart in
outburst. The new psr appears to be geometrically very similar (from
orbit), and it is now anti-Sun, ideal for optical/IR obs. We are
obtaining Magellan optical/IR obs of field, but cannot obtain opt
spectra until 2 arcmin position improved, since field crowded. Also,
J1808 showed strange IR/radio excess early in 1998 outburst that may
have been synchtroton (ApJ, 563, L61); if so, soft X-ray sync excess
also expected, possibly with jets, a first for a NS/pulsar. J1808 was
never observed with CXO in outburst. We request ACIS/HETG for 10 ks to
(1) localize source, (2) look for soft excess/extension, (3) spectrum,
(4) HETG to limit pileup.