What's New for CIAO

07 Nov 2006

CALDB version 3.2.4 has been released. This release contains ACIS time-dependent gain calibration files only. See the How CALDB 3.2.4 Affects Your Analysis section of the CIAO release notes and the CALDB release notes for details.

Download CALDB 3.2.4

06 Nov 2006

Due to server maintenance, the CIAO webpages may be unavailable from 6:00 PM (EST) on Thursday, November 9 through 9:00 AM on Monday, November 13.

The Leicester Mirror Site will be available if you need access to CIAO documentation.

10 Aug 2006

CALDB version 3.2.3 has been released. The calibration changes in this release affect users of HRC-I data only. See the How CALDB 3.2.3 Affects Your Analysis section of the CIAO release notes and the CALDB release notes for details.

Download CALDB 3.2.3

31 July 2006

New webpage: Effective Area Cross-calibration Results Involving the Chandra X-ray Observatory

This webpage provides a discussion of cross-calibration work relating the Chandra X-ray Observatory to other X-ray missions, particularly XMM-Newton. Much of this webpage was developed in cooperation with the XMM-Newton calibration team.

19 June 2006

Update: The CIAO Software Survey is now over.

The CXC is planning a release of the CIAO software which includes infrastructure changes and improvements to the Sherpa modeling and fitting package and the CHIPS plotting and visualization package. We would like to get input on how the CIAO community is using the current user interfaces: command language or S-Lang commands; interactive use or scripts.

15 May 2006

CALDB version 3.2.2 has been released. See the How CALDB 3.2.2 Affects Your Analysis section of the CIAO release notes and the CALDB release notes for details.

Download CALDB 3.2.2

24 Apr 2006

New thread: Correcting Absolute Astrometry with reproject_aspect

reproject_aspect applies corrections for translation, scale, and rotation to the WCS of a file by comparing two sets of source lists from the same sky region. If three or more sources are found to be a close match in position, the tool calculates the transformation that relates the two files and updates the WCS mapping from SKY(X,Y) to (RA,Dec) either by modifying the aspect solution or by revising the WCS keywords, depending on how the parameters are set.

4 Apr 2006

Three new threads have been released:

• Overview: Reprojecting Files

• Reprojecting Images: Making an Exposure-corrected Mosaic

• Source Position for Grating Data with a Piled or Blocked Zero Order

3 Apr 2006

Reprocessing III, a complete reprocessing of all observations in the Chandra Data Archive, began in February 2006. The quality of the reprocessed data will be improved over the current data in the archive due to updates in software and calibration. The Reprocessing III of Chandra Data webpage has details on the reprocessing schedule and the specific software and calibration changes that are included.

31 Mar 2006

The recommended use for the specextract script has been changed. It has been determined that the mkwarf tool, which is used for ARF generation by specextract, may not produce accurate results for point sources. The mkarf tool, used by psextract, is preferred for point source extraction.

specextract should be used for the analysis of extended sources only. Users working with point sources should instead use the psextract script.

Analysis of point sources that was done with mkwarf/specextract should be redone with mkarf/psextract for the most accurate results, e.g. taking bad columns into account.

Related threads:

• Using specextract to Extract ACIS Spectra and Response Files
• Using psextract to Extract ACIS Spectra and Response Files for Pointlike Sources

3 March 2006

Update: Removal of support for QPOE files in CIAO

The CXC will end the support of PROS-style QPOE files as of the CIAO 4 release. These files are currently only supported in the Solaris version of CIAO.

1 Feb 2006

New thread: Using specextract to Extract ACIS Spectra and Response Files

specextract, a new script for creating ACIS spectra, was released in CIAO 3.3. It allows the user to create source and background PHA or PI spectra and the associated ARF and RMF files for both point and extended sources. specextract also has the ability to determine when mkacisrmf should be used in place of mkrmf.

Users are encouraged to start using specextract in place of psextract and acisspec for new analyses.

27 Jan 2006

New thread: Using Data Cubes

The CIAO data model allows you to filter and manipulate 3-dimensional images, known as "data cubes." You can select 3-dimensional subsets, or slice out 2-dimensional pieces. If two dimensions of the cube represent a pair of position axes, you can apply a region filter to those axes. In this thread we show how to create and filter data cubes in CIAO.

19 Jan 2006

Removal of support for QPOE files in CIAO

The CIAO development team is planning to end the support of PROS-style QPOE files in future CIAO releases. QPOE files were IRAF's photon event list implementation and were mostly used in the ROSAT-era PROS analysis system. They are currently supported in the Solaris version of CIAO.

If you think that the lack of QPOE support in CIAO would hamper your data analysis, please let us know by sending e-mail to cxchelp@cfa.harvard.edu and describing your situation. Unless we hear strong objections from the community, we plan to stop supporting QPOE files in the next CIAO release.

12 Jan 2006

CIAO 3.3 has been patched to CIAO 3.3.0.1. The patch contains a PIMMS effective area file upgrade required for Cycle 8 proposal planning.

Download CIAO 3.3.0.1

15 Dec 2005

CALDB version 3.2.1 has been released. See the How CALDB 3.2.1 Affects Your Analysis section of the CIAO release notes and the CALDB release notes for details.

Download CALDB 3.2.1

21 Nov 2005

The CIAO 3.3 software release is now available. Read the release notes for full details.

CALDB version 3.2.0 has also been released; see the release notes for details.

CIAO 3.3 requires that you have at least version 3.1.0 of the CALDB. We recommend that you upgrade to CALDB 3.2.0 in order for your analysis to keep pace with the current calibration standards.