CDA - Reprocessing III
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- The archive is fully functional.
Reprocessing IV has been completed in December 2014.
- ASCDSVER: 10.11.1
- CALDBVER: 4.10.4
- Electrical Outage 11/05/21 - 11/06/21
There will be a planned electrical outage Friday, November 5 2021, 5:30PM - Saturday, November 6 2021, 6:00PM EDT. During this time period ChaSeR and other archive interfaces will be unavailable.
- Electrical Outage on 07/28/21
There will be a planned electrical outage Wednesday, July 28 2021, 8:00PM - 10:00PM EDT. During this time period ChaSeR and other archive interfaces will be unavailable.
- Downtime on 6/12/21
Due to electrical work, the public interfaces of the Chandra Data Archive will not be available on Saturday 6/12 from 4 AM to 9 PM.
- Repro V Begins
The fifth major reprocessing of the archive (Repro V) has started! Details can be found here.
- Past Notices
The third reprocessing series consists of one large reprocessing project and a few smaller ones:
- Reprocessing III: Uniform calibration of almost all
data in the archive
This run consists of a complete reprocessing of all data obtained between 29 January 2000 and 15 November 2005. The aim of this run was to provide a complete set of archived data, processed with a uniform calibration database from the moment the frontend temperature went to -120° C, in January 2000. Details of the changes may be found below. This bulk of this processing run was performed between February 2006 and June 2007.
- Reprocessing IIIa: Aspect correction for early 2007
During the August 2007 we reprocessed observations made between December 2006 and May 2007, using an updated aspect calibration. That correction is only needed for this particular set of observations.
More specifically: It affects all data obtained after 2006-12-10 and processed on or before 2007-05-22. These data were subject to a systematic aspect offset of approximately 0.4 arcsec, believed to be the result of a changed thermal environment following the procedure to cool the ACA CCD from -15° C to -19° C that took place between late Nov-2006 and early Jan-2007. This error has been corrected in the newly processed version of the data.
More information is available at this location.
- Reprocessing IIIb: Override Obspar
- Reprocessing IIIc: Calibration update of all HRC-I
observations since 29 January 2000
The following concerns HRC-I observations only and is of interest to you if one or more of the following apply:
- you have performed hardness ratio or quantile color-color analysis
- your analysis was particularly sensitive to the Enclosed Count Fraction (ECF)
- your sources were close to on-axis in observations witha large SIM-Z offset
- Reprocessing IIId: Problem Obsids
Reprocessing III: Uniform calibration of almost all data in the archive
Summary of Changes for Reprocessing III of Chandra Data
The main component of the third reprocessing run of Chandra data was started in February 2006 and covers most of the mission. It began with data from January 2005 and ran through November 2005; then it went back to December 2004 and is running backwards to the moment when the frontend temperature went down to -120° C, in January 2000; the very early part of the mission may be reprocessed later. The quality of the reprocessed data will be better because of improvements in software and, especially, calibration since the current default data in the archive were created.
Whether the new data version would affect any scientific conclusion drawn on the basis of the older versions depends on many factors: the nature of the conclusions, the type of analysis, the signal-to-noise ratio, etc. Ultimately, the user may need to make a comparison in order to judge whether the changes are significant for her or his purposes, but to aid in that assessment we have summarized in the following tables the most significant CalDB and software changes. There are three keywords in the headers of all CXC FITS data products that indicate what version those products were processed with:
- DATE: The date and time of the file's creation (in UTC)
- ASCDSVER: The CXC-DS software release version used
- CALDBVER: The CalDB version used for creating the data product
The values of these keywords should be looked up in older versions of data products and used when consulting the tables below in order to determine whether reprocessed products may differ significantly.
Note also, that the new products will be fully compatible with the current version of CIAO, something that is not necessarily the case for older data versions.
Major CalDB Changes
The following is a short summary of Chandra calibration (CalDB) upgrades that have affected various aspects of pipeline processing since the completion of the previous (second) round of archival reprocessing. The specific relevant portions of the CalDB are ACIS, HRC, PIXLIB (coordinate library), and PCAD (aspect).
|2005-12-15T17:30:00||3.2.1||BADPIX||-120° C Version N0003: Status bits changed on node boundary chips so they are not counted as normal bad columns. Hence adjacent columns will not be automatically included in the *bpix1.fits primary data files.|
|2005-11-16T16:00:00||3.2.0||CTI||Version N0005 Epochs 1-22 (to May 2005)
Due to the CTI time-dependence added in CTI N0005 files below, T_GAIN is now approximately re-zeroed at the start of Epoch 11, which is August 1, 2002, for the FI chips ONLY!
BI chips T_GAIN corrections have not yet been affected by CTI correction, because no CTI correction has been released for them.
Epochs 21 and 22 are added; however all files have been changed to include a higher-density spatial grid, which eliminates a calibration problem, to wit a gain-sag most notably at high energies near the central 50 columns of each chip.
|2005-11-16T16:00:00||3.2.0||DETGAIN||CTI files version N0005, time-dependence added to FI chips to account for decay in their resolution with time. Two files have been included, for T_GAIN epochs 1-10 and 11-current. Only the S2 data for epochs 1-10 are updated with a better model. (BI chip CTI corrections are not yet included.)|
|2005-11-15T15:30:00||3.2.0||BADPIX||An improved bad pixel map|
|2005-06-23T15:17:00||3.1.0||TGAIN||Time-dependent gain corrections to the PHA in Level 1|
|2005-06-23T15:17:00||3.1.0||CTI||Phase 2 response gains for Chips 4, 8, and 9 (S0,4,5), making the set complete for use with mkacisrmf.|
|2004-12-14T18:00:00||3.0.0||DETGAIN||S1-3, I0-3 gain function modifications (improved gain model) near the Si-K edge|
|2004-12-14T18:00:00||3.0.0||DETGAIN||S1 gain function improvements for imaging and grating (order-sorting) observations|
|2005-11-16T16:00:00||3.2.0||GAINMAP||Gain maps included in processing for HRC-I for the first time, version N0001. Second file applies to all data after HV was reduced in the HRC-I, on 1999-10-04.|
|2005-11-16T16:00:00||3.2.0||DEGAP||Improved gap removal calibrations for HRC-S. For a complete
GAPLOOKUP version N0002: This file is the first iteration of corrections for the known non-linearity in the HRC-S/LETG spatial wavelength scale that has been frequently alluded to in the literature.
|2004-08-11T19:30:00||2.28||BADPIX||Upgrades to the bad pixel map for HRC-S.
This new file has a time-dependent addition for a rectangular hot spot on plate 1 of HRC-S, which recently became enlarged.
|2002-04-04T15:05:00||2.13||BADPIX||Upgrades to the bad pixel map for HRC-I|
|2002-11-08T00:00:00||2.4||EVENT FILTER||Upgrades to event tests to eliminate ghost images and some background events, such as event flatness, tapringing, amplifier saturation, and f-p test|
|2001-03-07T14:50:00||2.3||EVENT FILTER||HRC-S GAIN and PI region filters for background elimination|
|2001-01-25T18:00:00||2.2||DEGAP||Improved gap removal calibrations for HRC-I|
|2003-12-30T14:00:00||2.25||ASTROMETRY||Astrometry corrections to within 0.2 arc seconds on axis, in particular for ACIS|
|2005-02-15T16:45:00||3.0.1||AIMPOINTS||Version N0002, HRC-S imaging default aimpoint added.|
|2005-02-15T16:45:00||3.0.1||GEOM||Improved chip corner positions to correct the HETG/ACIS-S
wavelength/energy scale to within prelaunch specifications.
Version N0005 includes ACIS-S chip corner positions modifications for chips 4, 5, 6, 8, and 9. (ACIS-I0-3 and ACIS-7 are not changed.) These corrections, while having negligible affect on the imaging astrometry for ACIS-S, eliminate wavelength errors of the order .002 Angstroms in the HETG and LETG spectra with ACIS-S. Further an adjustment to the MEG period has been included, which makes the HEG and MEG spectra more mutually consistent.
|2001-10-22T16:00:00||2.9||GEOM||Off-axis astrometry improvements for outlying ACIS chips. spectra more mutually consistent.|
Other areas of the CalDB have been significantly upgraded since the second reprocessing run, e.g., the response input data for ACIS (CalDB 3.2.0), the spatially-dependent ACIS OBF contamination correction (CalDB 3.0.0), the LSF parameter input data for grating RMFs (CalDB 2.27, 2.28), the upgrades in the detector quantum efficiencies and uniformities (CalDB 2.9 for HRC-I, 2.28 for ACIS, 3.0.1 for HRC-S), and the HRMA effective area modifications (CalDB 3.2.1). However, these do not directly affect processing through Level 2 which is the work of the current reprocessing run. Nevertheless, the reprocessing of the older data does allow these new analysis-level calibrations to be applied more appropriately and directly to archival data (i.e. without user reprocessing or custom processing). Hence reprocessing will make the latest and best Chandra calibrations more immediately applicable for the bulk of the archive.
Major Software Changes
Updates will that will change and/or improve standard pipeline data products
|Date||DS software version||Description|
|2004-06-25||7.3.1||No change (most data are still labeled as 7.3.0)|
|2004-04-26||7.2.2||No change (most data are still labeled as 7.2.1)|
|2003-10-06||7.0.3||No change (some data labeled as 7.0.2)|
|2003-05-06||6.12.0 (6.11.0 deployed at the same time)||
|2003-05-06||6.11.0 (deployed at the same time as 6.12.0)||
Reprocessing IIIa: Aspect correction for early 2007
Follow this link.
Reprocessing IIIb: Override Obspar
Reprocessing IIIc: Calibration update of all HRC-I observations since 29 January 2000
During the third Chandra Reprocessing run (January 2006 - September 2007) all observations since 29 January 2000, including those made by HRC-I, were processed with a new common set of calibrations. However, since the start of that run there have been significant improvements in two calibration areas for HRC-I: the gain map (GMAP) and DEGAP (GAPLOOKUP). We have decided to perform a supplemental reprocessing of all HRC-I observations since Feb 2000 in order to update all of them to the latest gain and degap calibrations; This is designated as Reprocessing Run 3C.
The GMAP is used to generate PI values from PHA values in the event list. The PI values may be used to estimate hardness ratios, and to perform quantile color-color analyses of HRC-I observed sources. If your analyses have included hardness ratios or quantile color-color analysis, or you would like to perform such analyses of your sources, you may wish to review the Repro 3C processing of your observations.
The upgrades to the GAPLOOKUP tables (see section III.B of the CalDB 3.4.1 Release Notes) for HRC-I have made minor, but still significant improvements to the encircled energy fraction for on-axes sources located at or near the nominal aimpoint position of HRC-I. The latest upgrade to GAPLOOKUP, which has been added as of September 14, 2007, makes significant improvements in the degap solution for on-axis source observations with a particular large SIM_Z offset, so that the source appears in CRSU = 12-13 region, and small improvements elsewhere. If your analyses are particularly sensitive to the ECF, you may want to review your results with the Repro 3C processing of your observations.
Reprocessing IIId: Problem Obsids