CalDB 4.12.3 Public Release Notes

I. INTRODUCTION

CalDB 4.12.3 is an upgrade to the Chandra CalDB, which includes the following items:

• ACIS CONTAM version N0016
• HRC-I QE vN0017 File Set (43 new files)
• PCAD ACA-P DARK_CURR periodic update #12 (4 new files)
• PIMMS Cycle 28 Effective Areas

For the CIAO 4.18 / CalDB 4.12.3 release notes see How CalDB 4.12.3 Affects Your Analysis.

II. SUMMARY OF CHANGES

A. ACIS CONTAM version N0016

Location:	$CALDB/data/chandra/acis/contam/
Filename:	acisD1999-08-13contamN0016.fits

The ACIS calibration team has produced a new, updated CONTAM file, which extends the quasi-linear model for the optical depth of the overlayer out for two more years, since the previous update in 2023. The models are separate between ACIS-I and ACIS-S arrays, however the center-to-edge model has not changed for either array.

The model extends through the end of calendar year 2029 (same as the previous two versions). It has been tested against all of the most recent Mkn421 and E0102-72.3 (ACIS-S) and A1795 (ACIS-I) calibration observations, as well as being confirmed to be consistent with earlier calibration models for earlier observations. Because the N0015 model is not adequate for fitting the most recent data, the Cal team recommends the new file for immediate release.

See the ACIS QE CONTAM why page for basic information concerning ACIS contamination. For further details on the latest CONTAM N0014 effects on the ACIS aimpoint EAs, see the technical details below.

CIAO SCRIPTS/TOOLS AFFECTED:

See the CIAO scripts as follows:

• fluximage, which uses mkinstmap
• specextract, which uses mkwarf
• fullgarf, which uses mkgarf

THREADS AFFECTED:

For exposure-corrected imaging analysis with ACIS, see the threads:

• Single Chip ACIS Exposure Map and Exposure-corrected Image
• Multiple Chip ACIS Exposure Map and Exposure-corrected Image

For imaging spectroscopy with ACIS, see the threads:

• Extract Spectrum and Response Files for a Pointlike Source
• Extract Spectrum and Response Files for an Extended Source
• Extract Spectrum and Response Files for Multiple Sources

For grating spectroscopy with ACIS, see the threads:

• HETG/ACIS-S Grating ARFs
• LETG/ACIS-S Grating ARFs

B. HRC-I QE vN0017 File Set (43 new files)

Location:

$CALDB/data/chandra/hrc/qe/

Filenames:

hrciD1999-07-29qeN0017.fits hrciD2000-07-23qeN0017.fits hrciD2001-04-17qeN0017.fits hrciD2001-10-12qeN0017.fits hrciD2002-04-12qeN0017.fits hrciD2002-10-23qeN0017.fits hrciD2003-04-23qeN0017.fits hrciD2003-10-06qeN0017.fits hrciD2004-04-05qeN0017.fits hrciD2004-11-05qeN0017.fits hrciD2005-05-15qeN0017.fits hrciD2005-11-01qeN0017.fits hrciD2006-04-25qeN0017.fits hrciD2006-11-19qeN0017.fits hrciD2007-09-15qeN0017.fits hrciD2008-09-11qeN0017.fits hrciD2009-09-15qeN0017.fits hrciD2010-09-16qeN0017.fits hrciD2011-09-29qeN0017.fits hrciD2012-09-29qeN0017.fits hrciD2013-10-03qeN0017.fits hrciD2014-09-29qeN0017.fits hrciD2015-08-05qeN0017.fits hrciD2016-06-11qeN0017.fits hrciD2017-02-16qeN0017.fits hrciD2017-08-16qeN0017.fits hrciD2018-02-12qeN0017.fits hrciD2018-08-24qeN0017.fits hrciD2019-02-27qeN0017.fits hrciD2019-08-24qeN0017.fits hrciD2020-02-20qeN0017.fits hrciD2020-08-27qeN0017.fits hrciD2021-01-09qeN0017.fits hrciD2021-02-16qeN0017.fits hrciD2021-04-05qeN0017.fits hrciD2021-08-29qeN0017.fits hrciD2022-09-04qeN0017.fits hrciD2023-09-27qeN0017.fits hrciD2024-03-30qeN0017.fits hrciD2024-06-06qeN0017.fits hrciD2024-09-20qeN0017.fits hrciD2024-10-14qeN0017.fits hrciD2025-02-23qeN0017.fits

The HRC calibration team has generated an update (version 17) to the HRC-I time-dependent QE file set in CalDB, to include data derived from recent HRC-I/LETG HZ 43 observations. The new file set includes three additional files, the first effective as of 2024-06-06T00:00:00 (UTC) which includes the calibrations for the previous HV settings, and the third and final one, effective 2025-02-23T00:00:00 UTC, which will be the new default for current observations.

See the Technical Details section below for the HRC-I QE N0017 updates.

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 periodic update #12 (4 new files)

Location:	$CALDB/data/chandra/pcad/dark_curr/
Filename:	acapD2025-08-10darkN0002.fits acapD2025-09-10darkN0002.fits acapD2025-10-10darkN0002.fits acapD2025-11-01darkN0002.fits

The CXC Aspect Team has generated a twelfth set of ACAP DARK_CURR files, including three new 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 ~2-6 weeks apart, as with their previously released datasets. The new files are effective as of the respective dates given in the filnames in the Description of Change section below. These new files extend the date coverage for archival observations through 2025-11-01T00:00:00, 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 calls for the ASPECT CalDB files, including DARK_CURR.

THREADS AFFECTED:

None.

C. PIMMS Cycle 28 Effective Areas

Location:	$CALDB/data/chandra/pimms/acis/
Filenames:	acisiD2025-11-25pimmsN0028.fits acisihetg0D2025-11-25pimmsN0028.fits acisiletg0D2025-11-25pimmsN0028.fits acissD2025-11-25pimmsN0028.fits acissheg1D2025-11-25pimmsN0028.fits acisshegmeg1D2025-11-25pimmsN0028.fits acisshetg0D2025-11-25pimmsN0028.fits acissleg1D2025-11-25pimmsN0028.fits acissletg0D2025-11-25pimmsN0028.fits acissmeg1D2025-11-25pimmsN0028.fits
Location:	$CALDB/data/chandra/pimms/hrc/
Filenames:	hrciD2025-11-25pimmsN0028.fits hrciletg0D2025-11-25pimmsN0028.fits hrcsD2025-11-25pimmsN0028.fits hrcsleg1D2025-11-25pimmsN0028.fits hrcsleghiD2025-11-26pimmsN0028.fits hrcsletg0D2025-11-25pimmsN0028.fits

The Chandra Cycle 28 PIMMS effective areas have been generated and loaded into the DS10.13.1 software for release with the Cycle 28 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 28 PIMMS Effective Areas

Cycle 2 PIMMS Effective Area Public Information

PIPELINES/TOOLS AFFECTED:

PIMMS Effecive Area Viewer

PIMMS Count Rate Calculator

THREADS AFFECTED:

None.

III. TECHNICAL DETAILS