Bugs: tgextract - CIAO 3.4

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Matching CIAO and CALDB Versions

CIAO 3.4 requires CALDB 3.3.0 or higher to operate properly.

CALDB 3.4.0 and higher should not be used unless you are running CIAO 3.4 or CIAO 4.0.

Are your versions mismatched? Time to update CIAO and CALDB!

News Previous Items

11 Nov 2008

These are the webpages relative to the CIAO 3.4 release (18 December 2006). They are no longer actively updated, however the CXC will continue limited support of CIAO 3.4 for the near future.

CIAO 3.4 users should check the CALDB 3 website for compatible calibration updates.

15 Dec 2008

The newest version of the Chandra Interactive Analysis of Observations software, is CIAO 4.1, released on 15 December 2008. Read the release notes for detailed information. This release requires that CALDB 4.1.0 be installed for the software to work correctly.

Bugs

If you have a multi-source observation, you cannot extract with the CALDB bow-tie region for any source other than the first (tg_srcid=1).

The current implementation of tgextract defaults to a box without any error or warning.

DETCHANS header keyword not written to Type 2 PHA files (01 Dec 2006)

Type 2 PHA files produced by tgextract do not have the DETCHANS header keyword. Since tgextract is used to create the pha2.fits files in SDP, this affects all Chandra data, whether you've reprocessed in CIAO or not.

This is not a problem for Sherpa users, but causes an error in XSpec.

Workaround:

If you are analysing data in XSpec, add the DETCHANS keyword to the file header with dmhedit. The DETCHANS keyword value equals the length of the COUNTS array, whose default is 8192. It is an arbitrary number for gratings - whatever you specified in the grid.

Use dmlist to find the size of the array:

unix% dmlist acisf00459N002_pha2.fits cols | grep COUNTS
   8   COUNTS[8192]  count  Int2(8192)  0:32767  -1  Counts array (a spectrum)

Then run dmhedit:

unix% dmhedit infile=acisf00459N002_pha2.fits filelist="" \
      operation=add key=DETCHANS value=8192