Chandra X-Ray Observatory
	(CXC)
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Last modified: 27 August 2013

URL: http://cxc.harvard.edu/csc/data_products/usage/index.html

Using the L3 Data Products



The so-called "L3" data products are born in the Level=3 data processing pipeline developed to produce the continually growing Chandra Source Catalog. The L3 pipeline derives higher level information from the L2 outputs, including more precise source detection and characterization (fluxes, morphology), plus cross-correlation with other catalogs. Some of the L3 files are equivalent or very similar to their familiar L1 and L2 counterparts (or to the file output of CIAO threads which use L1 and L2 files); the nature of the differences are listed for the relevant data products in the table below. Perhaps the most interesting difference is that the L3 event files undergo background flare filtering, whereas the L2 event files do not. Furthermore, many of the L3 data products which come pre-packaged with the CSC, e.g. source spectra and light curves, are only produced with Level 1 and 2 files after following a series of CIAO processing and analysis threads. This results in the production of certain types of L3 files with multiple interesting CXC Data Model blocks (FITS HDUs); e.g., the full-field events image for a given science energy band contains three image blocks, one for each blocking factor (i.e., resolution). The various images contained in one L3 image file may be viewed simultaneously with the DS9 v5.6 menu item "File-->Open-->Open Other-->Open Ext Multi Frames."

The table below lists each L3 data product with a link to a full description; the CXC Data Model blocks (FITS HDUs) and columns for each; as well as a list of relevant CIAO threads and ahelp files. The CIAO documents labeled with an asterisk can be used together with L1 and/or L2 files to replicate or approximate the L3-equivalents. For example, the exp3.fits exposure maps are created as shown in the CIAO thread Multiple Chip ACIS Exposure Map, which requires files evt2, asol1, msk1, and pbk0.

Questions about the L3 data products should be submitted to the CXC Helpdesk.


Level 3 Data Products CXC DM Blocks and Columns Relevant CIAO documentation
Full-Field Event File
(evt3.fits)
EXAMPLE
CAUTION #1
ciao% dmlist evt3.fits blocks
ciao% dmlist evt3.fits cols
The destreak algorithm has been applied to the ACIS-S4 CCD of evt3.fits files. Good time intervals have been revised to eliminate periods of background flares. The evt3.fits file is similar to the evt2.fits file from the Chandra Data Archive, but has different GTIs due to the filtering of background flares.
Reprocessing Data to Create a New Level=2 Event File*

Filtering Lightcurves*
Full-Field Image File
(img3.fits, img3.jpg)
CAUTION #2
CAUTION #5
 
ciao% dmlist {e}_img3.fits blocks
ciao% dmlist {e}_img3.fits cols

{e} = science energy band (u, s, m, h, b, or w)
dmbinning ahelp file*

dmfiltering ahelp file*

True Color Images*

Single Chip ACIS Exposure Map and Fluxed Image*

Multiple Chip ACIS Exposure Map and Fluxed Image*

Match the Binning of an Image*
Full-Field Background Image File
(bkgimg3.fits)
CAUTION #2
CAUTION #5
ciao% dmlist {e}_bkgimg3.fits blocks
ciao% dmlist {e}_bkgimg3.fits cols

{e} = science energy band (u, s, m, h, b, or w)
wavdetect ahelp file (see 'defnbkgfile' file)

dmbinning ahelp file

dmfiltering ahelp file

Full-Field Exposure Map File
(exp3.fits)
CAUTION #5
 
ciao% dmlist {e}_exp3.fits blocks
ciao% dmlist {e}_exp3.fits cols

{e} = science energy band (u, s, m, h, b, or w)
The exp3.fits exposure maps are created as shown in the CIAO thread "Multiple Chip ACIS Exposure Map."
Multiple Chip ACIS Exposure Map and Fluxed Image*

Using merge_all to Compute ACIS Exposure Maps and Fluxed Images*
Full-Field Sensitivity Map File
(sens3.fits)
ciao% dmlist {e}_sens3.fits blocks
ciao% dmlist {e}_sens3.fits cols

{e} = science energy band (u, s, m, h, b, or w)
lim_sens ahelp file*
Aspect Histogram File
(ahst3.fits)
CAUTION #3
ciao% dmlist ahst3.fits blocks
ciao% dmlist ahst3.fits cols
The ahst3.fits file is generated by the asphist tool, as users would in CIAO data analysis.
asphist ahelp file*

Step-by-Step Guide to Creating ACIS Spectra for Pointlike Sources*

Using merge_all to Compute ACIS Exposure Maps and Fluxed Images*

Multiple Chip ACIS Exposure Map and Fluxed Image*

Bad Pixel File
(bpix3.fits)
	 
ciao% dmlist bpix3.fits blocks
ciao% dmlist bpix3.fits cols
For ACIS, the bpix3.fits file is the same as the bpix1.fits file from the Chandra Data Archive. The HRC bpix3.fits may have a newer degap correction applied than the bpix1.fits version.
Setting the Observation-Specific Bad Pixel

New ACIS Hot Pixel File: Identify ACIS Hot Pixels and Cosmic Ray Afterglows
Field of View File
(fov3.fits)
ciao% dmlist fov3.fits blocks
ciao% dmlist fov3.fits cols
The fov3.fits file may be slightly different than the fov1.fits from the Chandra Data Archive, due to the different GTIs from background flare filtering.
skyfov ahelp file
Source Region Event File
(regevt3.fits)
EXAMPLE
CAUTION #4
ciao% dmlist regevt3.fits blocks
ciao% dmlist regevt3.fits cols
dmfiltering ahelp file*
Source Region Image File
(regimg3.fits, regimg3.jpg)
CAUTION #2
CAUTION #5
ciao% dmlist {e}_regimg3.fits blocks
ciao% dmlist {e}_regimg3.fits cols

{e} = science energy band (u, s, m, h, b, or w)
dmbinning ahelp file*

dmfiltering ahelp file*
Source Region PHA File
(pha3.fits)
EXAMPLE
CAUTION #6
ciao% dmlist pha3.fits blocks
ciao% dmlist pha3.fits cols
Using psextract to Extract ACIS Spectra and Response Files for Pointlike Sources*

Coadding Spectra and Weighted Responses*
Source Region ARF
(arf3.fits)
EXAMPLE
ciao% dmlist arf3.fits blocks
ciao% dmlist arf3.fits cols
Using psextract to Extract ACIS Spectra and Response Files for Pointlike Sources*

Coadding Spectra and Weighted Responses*
Source Region RMF File
(rmf3.fits)
EXAMPLE
ciao% dmlist rmf3.fits blocks
ciao% dmlist rmf3.fits cols
Using psextract to Extract ACIS Spectra and Response Files for Pointlike Sources*

Coadding Spectra and Weighted Responses*
Source Region Exposure Map File
(regexp3.fits)
CAUTION #5
ciao% dmlist {e}_regexp3.fits blocks
ciao% dmlist {e}_regexp3.fits cols

{e} = science energy band (u, s, m, h, b, or w)
dmfiltering ahelp file

dmbinning ahelp file

Single Chip ACIS Exposure Map and Fluxed Image*

Multiple Chip ACIS Exposure Map and Fluxed Image*

Using merge_all to Compute ACIS Exposure Maps and Fluxed Images*
Source Region PSF File
(psf3.fits, psf3.jpg)
ciao% dmlist {e}_psf3.fits blocks
ciao% dmlist {e}_psf3.fits cols

{e} = science energy band (u, s, m, h, b, or w)
Create a PSF*
Light Curve File
(lc3.fits)
ciao% dmlist {e}_lc3.fits blocks
ciao% dmlist {e}_lc3.fits cols

{e} = science energy band (u, s, m, h, b, or w)
Basic Lightcurves*
Region File
(reg3.fits)
EXAMPLE
ciao% dmlist reg3.fits blocks
ciao% dmlist reg3.fits cols
dmregions ahelp file*

dmgroupreg ahelp file*

Creating Source and Background Files*

Using CIAO Region Files

Cautionary Items

#1

Some observations (OBIs) have CCDs removed from the L3 event files and related products to avoid bright, extended objects that would cause many spurious detections in the catalog processing pipeline. The L3 per-observation data products that have CCDs removed have the following comment in the (sometimes NULL) primary header:

COMMENT  Chandra Source Catalog Level 3 pipeline has removed data from
COMMENT  CCD(s) ACIS-${dd} prior to processing.  The effective DETNAM
COMMENT  is changed from ${detnam} to ${mm}.  Users of these
COMMENT  data should be aware that the CSC Level 3 products will not
COMMENT  match the Chandra Level 2 and earlier products in the Chandra
COMMENT  Data Archive.

The script csc_dropchip_msk1.sh is a modified version of the script used in the L3 pipeline to remove the CCD(s) from the msk1 file (which is used to make ARFs, instrument maps, field-of-view files, etc.). Since the mask file contains one FITS HDU per CCD, a simple 'dmcopy' command won't do; the file has be to de-/re-constructed HDU by HDU.


#2

In many L3 image files, "NaN" values are used to represent data that is outside the field of view (e.g., in the full-field exposure-corrected images where [0 counts / 0 exposure]).

Users should be cautioned that performing seemingly simple operations with the affected files may cause programs to run very, very slow, e.g. using ds9's built in 'smoothing' operation or the tool dmimgcalc. The reason is that whenever the NaN values are encountered, a SIGFPE is generated and has to be dealt with; most applications choose to ignore SIGFPEs, but mechanically, they are still processed and use up significant CPU time.

Furthermore, performing any FFT-based operation (e.g., csmooth, wavdetect, aconvolve, apowerspectrum, etc.) will (a) take a very long time, and (b) will yield an output that is all NaNs. Since every pixel contributes to every frequency in Fourier space, and any operation with a NaN yields another NaN, all the output pixels are NaN.

CIAO users can replace NaN values with zeros (or any other value) accordingly:

ciao%   dmimgthresh in.fits out.fits cut=INDEF value=0

#3

CIAO users should be sure to specify a block extension of the ahst3.fits file ("ahst3.fits[asphist{#}]") in the parameters of tools/scripts which accept aspect histogram files (not asol1.fits), e.g. the 'obsfile' parameter of mkinstmap and the 'asphistfile' parameter of mkexpmap.


#4

CIAO users should note that the L3 source region event file, regevt3.fits, is not equal in size to the source region stored in the region file reg3.fits file (FITS HDU 'SRCREG'); it contains a rectangular SKY region equal in size to the background region of interest (ROI) corresponding to the detected source region.


#5

DS9 v5.5 users should note the caveats associated with the menu item "File-->Open-->Open Other-->Open Ext Multi Frames", which allows for simultaneous viewing of multiple images contained in one file:

* this feature does not work if the file is gzipped
* the first 'interesting' block is not always displayed
* GTI blocks are opened in their own frames as blank images

These issues are resolved in DS9 v5.6.


#6

To use the CSC source region PHA spectrum file (pha3) with the XSPEC X-ray spectral fitting package, it may be necessary to manually split the file into separate source region and background region spectra prior to analysis. To do so, use the CIAO tool 'dmcopy', as follows:

ciao% dmcopy pha3.fits"[SPECTRUM1]" src_spec.fits
ciao% dmcopy pha3.fits"[SPECTRUM2]" bkg_spec.fits


CXC Data Model Blocks and Columns

evt3.fits for ObsID 2180

ciao: dmlist acisf02180_000N001_evt3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_evt3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PRIMARY                        Null        
Block    2: EVENTS                         Table        15 cols x 45039    rows
Block    3: GTI7                           Table         2 cols x 1        rows
Block    4: GTI5                           Table         2 cols x 1        rows
Block    5: GTI2                           Table         2 cols x 1        rows
Block    6: GTI6                           Table         2 cols x 1        rows
Block    7: GTI3                           Table         2 cols x 1        rows
Block    8: GTI8                           Table         2 cols x 2        rows

ciao: dmlist acisf02180_000N001_evt3.fits cols
 
--------------------------------------------------------------------------------
Columns for Table Block EVENTS
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   time                 s            Real8          117172670.5632600039:117177787.8759600073 S/C TT corresponding to mid-exposure
   2   ccd_id                            Int2           0:9                  CCD reporting event
   3   node_id                           Int2           0:3                  CCD serial readout amplifier node
   4   expno                             Int4           0:2147483647         Exposure number of CCD frame containing event
   5   chip(chipx,chipy)    pixel        Int2           1:1024               Chip coords
   6   tdet(tdetx,tdety)    pixel        Int2           1:8192               ACIS tiled detector coordinates
   7   det(detx,dety)       pixel        Real4          0.50:     8192.50    ACIS detector coordinates
   8   sky(x,y)             pixel        Real4          0.50:     8192.50    sky coordinates
   9   pha                  adu          Int4           0:36855              total pulse height of event
  10   pha_ro               adu          Int4           0:36855              total read-out pulse height of event
  11   energy               eV           Real4          0:  1000000.0        nominal energy of event (eV)
  12   pi                   chan         Int4           1:1024               pulse invariant energy of event
  13   fltgrade                          Int2           0:255                event grade, flight system
  14   grade                             Int2           0:7                  binned event grade
  15   status[4]                         Bit(4)                              event status bits
 
--------------------------------------------------------------------------------
World Coord Transforms for Columns in Table Block EVENTS
--------------------------------------------------------------------------------
 
ColNo    Name
5:    CPC(CPCX) = (+0)[mm] +(+0.0240)* (chip(chipx)-(+0.50))
         (CPCY)   (+0)      (+0.0240)  (    (chipy) (+0.50))
7:    MSC(PHI  ) = (+0)[deg] +TAN-P[(+0.000136667)* (det(detx)-(+4096.50))]
         (THETA)   (+0)             (+0.000136667)  (   (dety) (+4096.50)) 
8:    EQPOS(RA ) = (+16.5804)[deg] +TAN[(-0.000136667)* (sky(x)-(+4096.50))]
           (DEC)   (+0.8159 )           (+0.000136667)  (   (y) (+4096.50)) 

ahst3.fits for ObsID 2180

ciao: dmlist acisf02180_000N001_ahst3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_ahst3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PRIMARY                        Null        
Block    2: asphist2                       Table         4 cols x 470      rows
Block    3: GTI                            Table         2 cols x 1        rows
Block    4: asphist3                       Table         4 cols x 470      rows
Block    5: asphist5                       Table         4 cols x 470      rows
Block    6: asphist6                       Table         4 cols x 470      rows
Block    7: asphist7                       Table         4 cols x 470      rows
Block    8: asphist8                       Table         4 cols x 470      rows



ciao: dmlist acisf02180_000N001_ahst3.fits cols
 
--------------------------------------------------------------------------------
Columns for Table Block asphist2
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   CAH_REC              bin          Int4           -                    histogram bin
   2   POS_OFFSET(X_OFFSET,Y_OFFSET) pixel        Real8          -Inf:+Inf            Offset in x (Central Pixel)
   3   ROLL_OFFSET          deg          Real8          -Inf:+Inf            Offsets in roll(Central radian)
   4   DURATION             s            Real8          -Inf:+Inf            Bin Duration (corrected for LT and GTI)
 
--------------------------------------------------------------------------------
World Coord Transforms for Columns in Table Block asphist2
--------------------------------------------------------------------------------
 
ColNo    Name
2:    POS_OFFBIN(X_OFFBIN) = (+1.0)[bin] +(+0.9840)* (POS_OFFSET(X_OFFSET)-(-29.3985))
                (Y_OFFBIN)   (+1.0)       (+0.9840)  (          (Y_OFFSET) (-21.3243))
2:    POS_OFFDEG(X_OFFDEG) = (+0)[degree] +(+0.000136667)* (POS_OFFSET(X_OFFSET)-(+0))
                (Y_OFFDEG)   (+0)          (+0.000136667)  (          (Y_OFFSET) (+0))
3:    ROLL_OFFBIN          = +1.0 [bin] +6.0 * (ROLL_OFFSET  -0.0734)

bpix3.fits for ObsID 2180

ciao: dmlist acisf02180_000N001_bpix3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_bpix3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PRIMARY                        Null        
Block    2: BADPIX2                        Table         6 cols x 116      rows
Block    3: BADPIX3                        Table         6 cols x 73       rows
Block    4: BADPIX5                        Table         6 cols x 126      rows
Block    5: BADPIX6                        Table         6 cols x 54       rows
Block    6: BADPIX7                        Table         6 cols x 138      rows
Block    7: BADPIX8                        Table         6 cols x 136      rows


ciao: dmlist acisf02180_000N001_bpix3.fits cols
 
--------------------------------------------------------------------------------
Columns for Table Block BADPIX2
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   SHAPE                             String[16]                          region shape
   2   COMPONENT                         Int2           0:36                 Component number
   3   CHIP(CHIPX,CHIPY)[2] pixel        Int2(2)        1:1024               CHIP X location
   4   TIME                 s            Real8          117172670.5632600039:117177787.8759600073 Time pixel went bad
   5   TIME_STOP            s            Real8          -Inf:+Inf            Time pixel went bad
   6   STATUS[4]            coded        Bit(4)                              Badpixel status code

Broad band bkgimg3.fits for ObsID 2180

ciao-137: dmlist acisf02180_000N001_b_bkgimg3.fits 
Option (cols): blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_b_bkgimg3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: IMAGE4                         Image      Real4(2048x2048)
Block    2: IMAGE2                         Image      Real4(2048x2048)
Block    3: IMAGE1                         Image      Real4(2048x2048)


ciao: dmlist acisf02180_000N001_b_bkgimg3.fits cols
 
--------------------------------------------------------------------------------
Columns for Image Block IMAGE4
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   IMAGE4[2048,2048]    count        Real4(2048x2048) -Inf:+Inf            
 
--------------------------------------------------------------------------------
Physical Axis Transforms for Image Block IMAGE4
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    sky(x) = (+0.50) +(+4.0)* ((#1)-(+0.50))
                 (y)   (+0.50)  (+4.0)  ((#2) (+0.50))
 
--------------------------------------------------------------------------------
World Coordinate Axis Transforms for Image Block IMAGE4
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    EQPOS(RA ) = (+16.5804)[deg] +TAN[(-0.000136667)* (sky(x)-(+4096.50))]
                   (DEC)   (+0.8159 )           (+0.000136667)  (   (y) (+4096.50)) 

Broad band exp3.fits for ObsID 2180

ciao: dmlist acisf02180_000N001_b_exp3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_b_exp3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: EXPMAP4                        Image      Real4(2048x2048)
Block    2: EXPMAP2                        Image      Real4(2048x2048)
Block    3: EXPMAP1                        Image      Real4(2048x2048)


ciao: dmlist acisf02180_000N001_b_exp3.fits cols
 
--------------------------------------------------------------------------------
Columns for Image Block EXPMAP4
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   EXPMAP4[2048,2048]   photon cm^-2 s^-1 Real4(2048x2048) -Inf:+Inf            
 
--------------------------------------------------------------------------------
Physical Axis Transforms for Image Block EXPMAP4
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    SKY(X) = (+2.50) +(+4.0)* ((#1)-(+1.0))
                 (Y)   (+2.50)  (+4.0)  ((#2) (+1.0))
 
--------------------------------------------------------------------------------
World Coordinate Axis Transforms for Image Block EXPMAP4
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    EQPOS(RA ) = (+16.5804)[deg] +TAN[(-0.000136667)* (SKY(X)-(+4096.50))]
                   (DEC)   (+0.8159 )           (+0.000136667)  (   (Y) (+4096.50)) 

Broad band sens3.fits for ObsID 2180

ciao: dmlist acisf02180_000N001_b_sens3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_b_sens3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: SENSITY                        Image      Real4(2048x2048)


ciao: dmlist acisf02180_000N001_b_sens3.fits cols
 
--------------------------------------------------------------------------------
Columns for Image Block SENSITY
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   SENSITY[2048,2048]   photon cm^-2 s^-1 Real4(2048x2048) -Inf:+Inf            
 
--------------------------------------------------------------------------------
Physical Axis Transforms for Image Block SENSITY
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    sky(x) = (+0.50) +(+4.0)* ((#1)-(+0.50))
                 (y)   (+0.50)  (+4.0)  ((#2) (+0.50))
 
--------------------------------------------------------------------------------
World Coordinate Axis Transforms for Image Block SENSITY
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    EQPOS(RA ) = (+16.5804)[deg] +TAN[(-0.000136667)* (sky(x)-(+4096.50))]
                   (DEC)   (+0.8159 )           (+0.000136667)  (   (y) (+4096.50)) 

Broad band img3.fits for ObsID 2180

ciao: dmlist acisf02180_000N001_b_img3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_b_img3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: IMAGE4                         Image      Real4(2048x2048)
Block    2: GTI7                           Table         2 cols x 1        rows
Block    3: GTI5                           Table         2 cols x 1        rows
Block    4: GTI2                           Table         2 cols x 1        rows
Block    5: GTI6                           Table         2 cols x 1        rows
Block    6: GTI3                           Table         2 cols x 1        rows
Block    7: GTI8                           Table         2 cols x 2        rows
Block    8: IMAGE2                         Image      Real4(2048x2048)
Block    9: IMAGE1                         Image      Real4(2048x2048)


ciao: dmlist acisf02180_000N001_b_img3.fits cols
 
--------------------------------------------------------------------------------
Columns for Image Block IMAGE4
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   IMAGE4[2048,2048]    photon cm^-2 s^-1 Real4(2048x2048) -Inf:+Inf            
 
--------------------------------------------------------------------------------
Physical Axis Transforms for Image Block IMAGE4
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    sky(x) = (+0.50) +(+4.0)* ((#1)-(+0.50))
                 (y)   (+0.50)  (+4.0)  ((#2) (+0.50))
 
--------------------------------------------------------------------------------
World Coordinate Axis Transforms for Image Block IMAGE4
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    EQPOS(RA ) = (+16.5804)[deg] +TAN[(-0.000136667)* (sky(x)-(+4096.50))]
                   (DEC)   (+0.8159 )           (+0.000136667)  (   (y) (+4096.50)) 

fov3.fits file for ObsID 2180

ciao: dmlist acisf02180_000N001_fov3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_fov3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PRIMARY                        Null        
Block    2: FOV                            Table         7 cols x 6        rows


ciao: dmlist acisf02180_000N001_fov3.fits cols
 
--------------------------------------------------------------------------------
Columns for Table Block FOV
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   POS(X,Y)[13]         pixel        Real8(13)      -Inf:+Inf            Position
   2   SHAPE                             String[16]                          Region shape type
   3   R[2]                 pixel        Real8(2)       -Inf:+Inf            Radius
   4   ROTANG[2]            pixel        Real8(2)       -Inf:+Inf            Angle
   5   COMPONENT                         Int2           -                    Component number
   6   CCD_ID                            Int2           -                    CCD ID
   7   EQPOS(RA,DEC)[13]    degree       Real8(13)      -360.0:      360.0   

regevt3.fits file for a source in ObsID 2180

ciao: dmlist acisf02180_000N001_r0002_regevt3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_r0002_regevt3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PRIMARY                        Null        
Block    2: EVENTS                         Table        15 cols x 60       rows
Block    3: GTI7                           Table         2 cols x 1        rows


ciao: dmlist acisf02180_000N001_r0002_regevt3.fits cols
 
--------------------------------------------------------------------------------
Columns for Table Block EVENTS
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   time                 s            Real8          117172670.5632600039:117177787.8759600073 S/C TT corresponding to mid-exposure
   2   ccd_id                            Int2           0:9                  CCD reporting event
   3   node_id                           Int2           0:3                  CCD serial readout amplifier node
   4   expno                             Int4           0:2147483647         Exposure number of CCD frame containing event
   5   chip(chipx,chipy)    pixel        Int2           1:1024               Chip coords
   6   tdet(tdetx,tdety)    pixel        Int2           1:8192               ACIS tiled detector coordinates
   7   det(detx,dety)       pixel        Real4          0.50:     8192.50    ACIS detector coordinates
   8   sky(x,y)             pixel        Real4          0.50:     8192.50    sky coordinates
   9   pha                  adu          Int4           0:36855              total pulse height of event
  10   pha_ro               adu          Int4           0:36855              total read-out pulse height of event
  11   energy               eV           Real4          0:  1000000.0        nominal energy of event (eV)
  12   pi                   chan         Int4           1:1024               pulse invariant energy of event
  13   fltgrade                          Int2           0:255                event grade, flight system
  14   grade                             Int2           0:7                  binned event grade
  15   status[4]                         Bit(4)                              event status bits
 
--------------------------------------------------------------------------------
World Coord Transforms for Columns in Table Block EVENTS
--------------------------------------------------------------------------------
 
ColNo    Name
5:    CPC(CPCX) = (+0)[mm] +(+0.0240)* (chip(chipx)-(+0.50))
         (CPCY)   (+0)      (+0.0240)  (    (chipy) (+0.50))
7:    MSC(PHI  ) = (+0)[deg] +TAN-P[(+0.000136667)* (det(detx)-(+4096.50))]
         (THETA)   (+0)             (+0.000136667)  (   (dety) (+4096.50)) 
8:    EQPOS(RA ) = (+16.5804)[deg] +TAN[(-0.000136667)* (sky(x)-(+4096.50))]
           (DEC)   (+0.8159 )           (+0.000136667)  (   (y) (+4096.50)) 

Broad band regimg3.fits file for a source in ObsID 2180

ciao: dmlist acisf02180_000N001_r0002b_regimg3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_r0002b_regimg3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: IMAGE                          Image      Real4(51x43)


ciao: dmlist acisf02180_000N001_r0002b_regimg3.fits cols
 
--------------------------------------------------------------------------------
Columns for Image Block IMAGE
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   IMAGE[51,43]         photon cm^-2 s-1 Real4(51x43)   -Inf:+Inf            
 
--------------------------------------------------------------------------------
Physical Axis Transforms for Image Block IMAGE
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    sky(x) = (+4072.80  ) +(+1.0)* ((#1)-(+0.50))
                 (y)   (+4006.1499)  (+1.0)  ((#2) (+0.50))
 
--------------------------------------------------------------------------------
World Coordinate Axis Transforms for Image Block IMAGE
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    EQPOS(RA ) = (+16.5804)[deg] +TAN[(-0.000136667)* (sky(x)-(+4096.50))]
                   (DEC)   (+0.8159 )           (+0.000136667)  (   (y) (+4096.50)) 

pha3.fits file for a source in ObsID 2180

ciao: dmlist acisf02180_000N001_r0002_pha3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_r0002_pha3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PRIMARY                        Null        
Block    2: SPECTRUM1                      Table         4 cols x 1024     rows
Block    3: GTI7                           Table         2 cols x 1        rows
Block    4: SPECTRUM2                      Table         4 cols x 1024     rows


ciao: dmlist acisf02180_000N001_r0002_pha3.fits cols
 
--------------------------------------------------------------------------------
Columns for Table Block SPECTRUM1
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   CHANNEL              channel      Int4           1:1024               PI
   2   PI                   chan         Real8          1.0:     1024.0      pulse invariant energy of event
   3   COUNTS               count        Int4           -                    Counts
   4   COUNT_RATE           count/s      Real8          -Inf:+Inf            Rate

arf3.fits file for a source in ObsID 2180

ciao: dmlist acisf02180_000N001_r0002_arf3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_r0002_arf3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PRIMARY                        Null        
Block    2: SPECRESP                       Table         4 cols x 900      rows


ciao: dmlist acisf02180_000N001_r0002_arf3.fits cols
 
--------------------------------------------------------------------------------
Columns for Table Block SPECRESP
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   ENERG_LO             keV          Real4          -Inf:+Inf            Min Energy
   2   ENERG_HI             keV          Real4          -Inf:+Inf            Max Energy
   3   SPECRESP             cm**2        Real4          -Inf:+Inf            Effective Area
   4   PSF_FRAC                          Real8          -Inf:+Inf            Fraction of PSF enclosed in SRC region

rmf3.fits file for a source in ObsID 2180

ciao: dmlist acisf02180_000N001_r0002_rmf3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_r0002_rmf3.fits 
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PRIMARY                        Null        
Block    2: RSP_MATRIX                     Table         6 cols x 900      rows
Block    3: EBOUNDS                        Table         3 cols x 1024     rows


ciao: dmlist acisf02180_000N001_r0002_rmf3.fits cols
 
--------------------------------------------------------------------------------
Columns for Table Block RSP_MATRIX
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   ENERG_LO             keV          Real4          -Inf:+Inf            label for field   1
   2   ENERG_HI             keV          Real4          -Inf:+Inf            label for field   2
   3   N_GRP                             Int2           -                    label for field   3
   4   F_CHAN                            Int2           1:1024               label for field   4
   5   N_CHAN                            Int2           -                    label for field   5
   6   MATRIX[552]          au           Real4(552)     -Inf:+Inf            label for field   6

Broad band regexp3.fits file for a source in ObsID 2180

ciao: dmlist acisf02180_000N001_r0002b_regexp3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_r0002b_regexp3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: EXPMAP                         Image      Real4(51x43)


ciao: dmlist acisf02180_000N001_r0002b_regexp3.fits cols
 
--------------------------------------------------------------------------------
Columns for Image Block EXPMAP
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   EXPMAP[51,43]        cm**2 sec    Real4(51x43)   -Inf:+Inf            
 
--------------------------------------------------------------------------------
Physical Axis Transforms for Image Block EXPMAP
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    SKY(X) = (+4073.30 ) +(+1.0)* ((#1)-(+1.0))
                 (Y)   (+4006.650)  (+1.0)  ((#2) (+1.0))
 
--------------------------------------------------------------------------------
World Coordinate Axis Transforms for Image Block EXPMAP
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    EQPOS(RA ) = (+16.5804)[deg] +TAN[(-0.000136667)* (SKY(X)-(+4096.50))]
                   (DEC)   (+0.8159 )           (+0.000136667)  (   (Y) (+4096.50)) 

Broad band psf3.fits file for a source in ObsID 2180

ciao: dmlist acisf02180_000N001_r0002b_psf3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_r0002b_psf3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PSF                            Image      Real8(51x43)


ciao: dmlist acisf02180_000N001_r0002b_psf3.fits cols
 
--------------------------------------------------------------------------------
Columns for Image Block PSF
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   PSF[51,43]                        Real8(51x43)   -Inf:+Inf            
 
--------------------------------------------------------------------------------
Physical Axis Transforms for Image Block PSF
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    SKY(X) = (+4072.80 ) +(+1.0)* ((#1)-(+0.50))
                 (Y)   (+4006.150)  (+1.0)  ((#2) (+0.50))
 
--------------------------------------------------------------------------------
World Coordinate Axis Transforms for Image Block PSF
--------------------------------------------------------------------------------
 
Group# Axis# 
   1   1,2    EQPOS(RA ) = (+16.5804)[deg] +TAN[(-0.000136667)* (SKY(X)-(+4096.50))]
                   (DEC)   (+0.8159 )           (+0.000136667)  (   (Y) (+4096.50)) 

Broad band lc3.fits file for a source in ObsID 2180

ciao: dmlist acisf02180_000N001_r0002b_lc3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_r0002b_lc3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PRIMARY                        Null        
Block    2: LIGHTCURVE                     Table         5 cols x 225      rows
Block    3: BKGLIGHTCURVE                  Table         5 cols x 225      rows


ciao: dmlist acisf02180_000N001_r0002b_lc3.fits cols
 
--------------------------------------------------------------------------------
Columns for Table Block LIGHTCURVE
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   Time                 s            Real8          117172670.5632600039:117177787.8759600073 
   2   COUNT_RATE           count/s      Real8          -Inf:+Inf            Rate
   3   COUNT_RATE_ERR       count/s      Real8          -Inf:+Inf            Rate Error
   4   Minus_3Sig           count/s      Real8          -Inf:+Inf            Expectation value minus 3 times sigma
   5   Plus_3Sig            count/s      Real8          -Inf:+Inf            Expectation value plus 3 times sigma

reg3.fits file for a source in ObsID 2180

ciao: dmlist acisf02180_000N001_r0002_reg3.fits blocks
 
--------------------------------------------------------------------------------
Dataset: acisf02180_000N001_r0002_reg3.fits
--------------------------------------------------------------------------------
 
     Block Name                          Type         Dimensions
--------------------------------------------------------------------------------
Block    1: PRIMARY                        Null        
Block    2: SRCREG                         Table         5 cols x 1        rows
Block    3: BKGREG                         Table         5 cols x 2        rows


ciao: dmlist acisf02180_000N001_r0002_reg3.fits cols
 
--------------------------------------------------------------------------------
Columns for Table Block SRCREG
--------------------------------------------------------------------------------
 
ColNo  Name                 Unit        Type             Range
   1   POS(X,Y)             pixel        Real8          -Inf:+Inf            Position
   2   SHAPE                             String[16]                          Region shape type
   3   R[2]                 pixel        Real8(2)       -Inf:+Inf            Radius
   4   ROTANG[2]            pixel        Real8(2)       -Inf:+Inf            Angle
   5   COMPONENT                         Int2           -                    Component number
 
--------------------------------------------------------------------------------
World Coord Transforms for Columns in Table Block SRCREG
--------------------------------------------------------------------------------
 
ColNo    Name
1:    EQSRC(RA_SRC ) = (+16.5804)[DEG] +TAN[(-0.000136667)* (POS(X)-(+4096.50))]
           (DEC_SRC)   (+0.8159 )           (+0.000136667)  (   (Y) (+4096.50)) 
3:    EQR                  = +0 [DEG] +0.000136667 * (R  -0)


Last modified: 27 August 2013
Smithsonian Institute Smithsonian Institute

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email:   cxchelp@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2017. All rights reserved.