CalDB 4.11.0 Public Release Notes

I. INTRODUCTION

CalDB 4.11.0 is an upgrade to the Chandra CalDB, which includes the following items:

• ACIS "warm" CTI corrections vN0011
• HRC-I QE vN0014 file set
• PCAD ACA-P DARK_CURR Files set #5
• PIMMS Cycle 26 Effective Areas

For the CIAO 4.16 / CalDB 4.11.0 release notes see How CalDB 4.11.0 Affects Your Analysis.

II. SUMMARY OF CHANGES

A. ACIS "warm" CTI corrections vN0011

Location:	$CALDB/data/chandra/acis/cti/
Filenames:	acisD2005-01-01ctiN0011.fits acisD2005-09-16ctiN0011.fits acisD2010-01-01ctiN0011.fits acisD2015-01-01ctiN0011.fits acisD2020-01-01ctiN0011.fits

Calibrations for "warm" FP_TEMPs have been generated for the four ACIS-I chips. Five new files have been generated, replacing the corresponding existing N0009 files with the same effective dates, beginning with the 2005-01-01 file.

Version N0011 of the CTI correction file contains improved CTI corrections for all four chips on ACIS-I up to focal plane temperatures of -107C. No changes are made for data taken with FP temperatures below -117C, or prior to 2005. The CTI correction for all six chips on ACIS-S remains the same as that in the prior version of the CTI correction file.

Prior versions of the CTI correction file used a linear correction with temperature, a single energy-dependent correction at all temperatures, and a single trap map at all temperatures. Version N0011 uses a quadratic function to model the temperature dependence of the CTI correction, a separate power-law energy-dependent correction in each temperature bin, and a separate trap map in each temperature bin.

Hence the new CTI N0011 files have 3-D trap density map extensions, one for each chip. The four ACIS-I chips have multiple trap maps in each extension, i.e. 1024x1024xn, where n is 4 for ACIS-0 and ACIS-2 and 5 for ACIS-1 and ACIS-3. The ACIS-S chips have a single 1024x1024x1 trap map each. Each n, or index value covers a range of FP_TEMP values, from -125 C to -105 C.

See the ACIS CTI Correction why page for more information.

PIPELINES/TOOLS AFFECTED:

ACIS L1 pipeline tool acis_process_events
CIAO reprocessing tool chandra_repro

THREADS AFFECTED:

Reprocessing Data to Create a New Level=2 Event File

B. HRC-I QE vN0014 file set

Location:

$CALDB/data/chandra/hrc/qe/

Filenames:

hrciD1999-07-29qeN0014.fits hrciD2000-07-23qeN0014.fits hrciD2001-04-17qeN0014.fits hrciD2001-10-12qeN0014.fits hrciD2002-04-12qeN0014.fits hrciD2002-10-23qeN0014.fits hrciD2003-04-23qeN0014.fits hrciD2003-10-06qeN0014.fits hrciD2004-04-05qeN0014.fits hrciD2004-11-05qeN0014.fits hrciD2005-05-15qeN0014.fits hrciD2005-11-01qeN0014.fits hrciD2006-04-25qeN0014.fits hrciD2006-11-19qeN0014.fits hrciD2007-09-15qeN0014.fits hrciD2008-09-11qeN0014.fits hrciD2009-09-15qeN0014.fits hrciD2010-09-16qeN0014.fits hrciD2011-09-29qeN0014.fits hrciD2012-09-29qeN0014.fits hrciD2013-10-03qeN0014.fits hrciD2014-09-29qeN0014.fits hrciD2015-08-05qeN0014.fits hrciD2016-06-11qeN0014.fits hrciD2017-02-16qeN0014.fits hrciD2017-08-16qeN0014.fits hrciD2018-02-12qeN0014.fits hrciD2018-08-24qeN0014.fits hrciD2019-02-27qeN0014.fits hrciD2019-08-24qeN0014.fits hrciD2020-02-20qeN0014.fits hrciD2020-08-27qeN0014.fits hrciD2021-01-09qeN0014.fits hrciD2021-02-16qeN0014.fits hrciD2021-04-05qeN0014.fits hrciD2021-08-29qeN0014.fits hrciD2022-09-04qeN0014.fits

New time-varying QE maps have been generated for HRC-I, based on the latest QE/QEU calibrations for the HRC-S. The QE manufacturing process is exactly as it was for version N0013 (the QE is adjusted by pasting the HRC-S QE shape at low energies and renormalized to generate the appropriate count rate in HZ 43 after accounting for QE loss due to gain drop by matching the HZ 43 scaled SUMAMPS profiles to an early-mission observation), with the following additional adjustments this time:

• The QE loss factor used to be limited to above 60 Ang, but is now extended to high energies, with a linear trend in wavelength accounting for ±1/2 the observed QE loss of 135 Ang at 0 Ang.

• Previously the HRC-S paste was smoothed out over a narrow 0.1 Ang wavelength band. Now it is smoothed out in the range (-25,+0.1) Ang.

Hence, a new set of 37 files have been generated for HRC-I, including three additional files relative to N0013. The final file becomes effective as of 2022-09-04.

PIPELINES/TOOLS AFFECTED:

CIAO tools/scripts fluximage and mkgarf

THREADS AFFECTED:

HRC-I Exposure Map and Exposure-corrected Image
LETG/HRC-I Grating ARFs

C. PCAD ACA-P DARK_CURR Files set #5

Location:	$CALDB/data/chandra/pcad/dark_curr/
Filenames:	acapD2023-08-29darkN0002.fits acapD2023-09-28darkN0002.fits acapD2023-10-17darkN0002.fits

The CXC Aspect Team has generated a fifth set of three (3) new ACAP time-displaced DARK_CURR files to support ACA background calculation and subtraction in the ASPECT L1 pipeline. The DARK_CURR files draw on an ever-growing database of ACA full field dark current data products which have been accumulated since the 1999:223 OAC dark current pixel map. Each version N0002 dark current fits file in the CALDB includes a 1024x1024 image with the processed full-field dark current map of the ACA CCD in e-/sec. Each file also includes header information with the ACA CCD temperature of the calibration, the reference date of the ACA dark current product, and the scale expected to be used to scale the calibration e-/sec to the effective e-/sec at the observed temperatures during observations.

The DARK_CURR files have effective dates (Cal Validity Start Date, or CVSD*) which are spaced several weeks apart, similar to their previously released datasets. The new files are effective as of the respective dates given above. These new files extend the date coverage for archival observations through 2023-10-17T00:00:00, with the final file being the one that will be the default file in standard data processing (SDP) until the next release/extension.

PIPELINES/TOOLS AFFECTED:

PCAD L1 pipeline tool asp_get_calib

THREADS AFFECTED:

None.

D. PIMMS Cycle 26 Effective Areas

Location:	$CALDB/data/chandra/pimms/acis/
Filenames:	acisiD2023-11-20pimmsN0026.fits acisihetg0D2023-11-20pimmsN0026.fits acisiletg0D2023-11-20pimmsN0026.fits acissD2023-11-20pimmsN0026.fits acissheg1D2023-11-20pimmsN0026.fits acisshegmeg1D2023-11-20pimmsN0026.fits acisshetg0D2023-11-20pimmsN0026.fits acissleg1D2023-11-20pimmsN0026.fits acissletg0D2023-11-20pimmsN0026.fits acissmeg1D2023-11-20pimmsN0026.fits
Location:	$CALDB/data/chandra/pimms/hrc/
Filenames:	hrciD2023-11-20pimmsN0026.fits hrciletg0D2023-11-20pimmsN0026.fits hrcsD2023-11-20pimmsN0026.fits hrcsleg1D2023-11-20pimmsN0026.fits hrcsleghiD2023-11-21pimmsN0026.fits hrcsletg0D2023-11-20pimmsN0026.fits

The Chandra Cycle 26 PIMMS effective areas have been generated and loaded into the DS10.12.3 software for release with the Cycle 26 Call for Proposals. These files are maintained in CalDB for use by the DS when it is ready to load the PIMMS files, and convert them into the usual PIMMS ASCII format for implementation and distribution to HEASARC, annually. See the links below for information on this cycle's PIMMS EAs:

Cycle 26 PIMMS Effective Areas

Cycle 26 PIMMS Effective Area Public Information

PIPELINES/TOOLS AFFECTED:

PIMMS Effecive Area Viewer

PIMMS Count Rate Calculator

THREADS AFFECTED:

None.