CalDB 4.9.8 Public Release Notes
Public Release Date: 16 JUN 2022
SDP Installation Date: 2022-06-15T19:37:14 (UTC)
I. INTRODUCTION
CalDB 4.9.8 is an upgrade to the Chandra CalDB, which includes the following items:
For the CIAO 4.14 / CalDB 4.9.8 release notes see How CalDB 4.9.8 Affects Your Analysis.
II. SUMMARY OF CHANGES
A. PCAD "CALALIGN" version N0010
| Location: | $CALDB/data/chandra/pcad/align/ |
| Filenames: | pcadD2013-01-19alignN0010.fits pcadD2013-07-02alignN0010.fits pcadD2014-01-01alignN0010.fits pcadD2014-07-02alignN0010.fits pcadD2015-01-01alignN0010.fits pcadD2015-07-02alignN0010.fits pcadD2016-01-01alignN0010.fits pcadD2016-07-02alignN0010.fits pcadD2017-01-01alignN0010.fits pcadD2017-07-02alignN0010.fits pcadD2018-01-01alignN0010.fits pcadD2018-07-02alignN0010.fits pcadD2019-01-01alignN0010.fits pcadD2019-07-02alignN0010.fits pcadD2020-01-01alignN0010.fits pcadD2020-07-02alignN0010.fits pcadD2021-01-01alignN0010.fits pcadD2021-07-02alignN0010.fits |
The ASPECT Calibration Team has just recently generated new PCAD "ALIGN" files, orignally designated "CALALIGN", updating the existing file set in CalDB for the first time since year 2013. The above 18 files, separated in six-month intervals, each include modified aca_misalign and fts_misalign in order to improve absolute aspect solution accuracy. The new values were determined using Chandra observations of well-determined X-ray sources, and comparing those with the latest tabulated positions of their optical counterparts. A table containing the actual updated calibration products is included in the technical details linked to this section.
PIPELINES/TOOLS AFFECTED:
Aspect L1 pipeline tool asp_get_calib, which writes the acacal apect supporting data product.
CIAO THREADS AFFECTED:
None. PCAD CalDB files are not referenced by any CIAO software.
B. HRC-I Grating Angle Corrections
| Location: | $CALDB/data/chandra/default/geom/ |
| Filename: | telD1999-07-23geomN0007.fits |
Improvements have been made for all three of the HRC-I/Grating angles (HEG, MEG, and LEG) in the PIXLIB GEOM file above in CalDB. The changes are small, but as illustrated in the associated Technical Details for this section, the apparent tilt in the grating dispersion versus wavelength across the HRC-I "axis" has been removed for all three grating arms. Users may apply these updates to archival HRC-I/Gratings observations using the chandra_repro script in CIAO.
PIPELINES/TOOLS AFFECTED:
CIAO 4.14 reprocessing tool chandra_repro; affects HRC-I/GRATING observations only.
THREADS AFFECTED:
C. HRC-S QE Uniformity version N0016
| Location: | $CALDB/data/chandra/hrc/qeu/ |
| Filenames: | hrcsD1999-07-22qeuN0016.fits hrcsD2000-01-01qeuN0016.fits hrcsD2001-01-01qeuN0016.fits hrcsD2002-01-01qeuN0016.fits hrcsD2003-01-01qeuN0016.fits hrcsD2004-01-01qeuN0016.fits hrcsD2005-01-01qeuN0016.fits hrcsD2006-01-01qeuN0016.fits hrcsD2007-01-01qeuN0016.fits hrcsD2008-01-01qeuN0016.fits hrcsD2009-01-01qeuN0016.fits hrcsD2009-08-08qeuN0016.fits hrcsD2010-09-14qeuN0016.fits hrcsD2012-03-29qeuN0016.fits hrcsD2012-10-05qeuN0016.fits hrcsD2013-09-21qeuN0016.fits hrcsD2015-02-17qeuN0016.fits hrcsD2016-02-22qeuN0016.fits hrcsD2016-07-28qeuN0016.fits hrcsD2017-01-23qeuN0016.fits hrcsD2017-06-05qeuN0016.fits hrcsD2017-09-26qeuN0016.fits hrcsD2018-01-19qeuN0016.fits hrcsD2018-05-27qeuN0016.fits hrcsD2018-09-26qeuN0016.fits hrcsD2019-02-24qeuN0016.fits hrcsD2019-08-22qeuN0016.fits hrcsD2020-01-16qeuN0016.fits hrcsD2020-07-22qeuN0016.fits hrcsD2021-05-14qeuN0016.fits hrcsD2021-09-02qeuN0016.fits |
Another full upgrade is being released to the QEU calibration data sets for HRC-S listed above. As stated in the previous release of the HRC-S QEU's, the secular time variations in the HRC-S response are subsumed into these numerous QEU maps.
See the HRC-S QE/QEU why page for information on the current HRC-S QE and QE Uniformity. See the technical details section below for illustrations and details of the derivation of these new QE Uniformity corrections.
SDP Pipeline / CIAO SCRIPTS/TOOLS AFFECTED:
The SDP pipeline procedure "tg_mk_responses" is used to generate single-source GARFs and GRMFs for HRC-S/LETG observations, to be ingested onto the archive. This procedure uses the HRC-S QEU library as loaded from the ARDLIB.
See the CIAO script fluximage, which uses mkinstmap.
THREADS AFFECTED:
For exposure-corrected imaging analysis with HRC-S, see the thread:
For grating spectroscopy with the LETG/HRC-S, see the thread:
D. PCAD "CALALIGN" old file header changes
| Location: | $CALDB/data/chandra/pcad/align/ |
| Filename: | pcadD{yyyy-mm-dd}alignN0008.fits |
The existing set of 49 PCAD ALIGN files with version N0008, extending in effective dates from the beginning of the mission until the end of year 2002, have had the Calibration Validity End Dates (CVED0001) and times (CVET0001) header keywords deleted from their Block 2 headers. These headers provide the single listing for each file in the PCAD branch CalDB index. The change is make these old files conform to the current standard for PCAD ALIGN CalDB specs in the Chandra CalDB. These changes have zero effect on current processing, and are listed here only for completeness.
PIPELINES/TOOLS AFFECTED:
None.
THREADS AFFECTED:
None.