Cycle 27 PIMMS Effective Area Public Information
Released as of 19 DEC 2024
The Chandra effective areas are built for sixteen configurations implemented in the PIMMS EA viewer and count rate calculator facility. Four of the configurations are for the default aim-point positions for each of the four detector arrays aboard Chandra, specifically the ACIS-I, ACIS-S, HRC-I and HRC-S detectors.
The other twelve configurations involve one or the other of the transmission gratings. For the HETG/ACIS-S configurations the default SIM_Z positions do not correspond to the above aim point settings, but instead are offset to minimize the ACIS CTI effect. A default SIM_Z offset of -3.0 mm (in the direction of the readouts) is used for HETG/ACIS-S.
As in previous years, model observations have been selected so that the zeroth order ARFs, as well as the first order GARFs will correspond to the appropriate positions on the ACIS-S array. The same is true for the LETG/HRC-S configuration, where the default zeroth order position does not necessarily coincide with the default imaging aim point.
PIMMS effective area (EA) files are built using model observations (OBSIDs) with standard/default detector and SIM_Z configurations with the CIAO 4.17 routines mkarf for imaging aimpoint cases and mkgarf for gratings configurations, using the most current CALDB input files (CALDB 4.11.6). The following table gives the input CALDB file information used by mkarf or mkgarf to generate the respective effective area files (as ARFs) for the Cycle 26 (N0026) and Cycle 27 (N0027) proposal cycles. Plots of the PIMMS effective areas may be viewed at the PIMMS Effective Area Data page. You may also use the automated Chandra Effective Area Viewer.
PIMMS Input Data and Procedure Changes for Cycle 27:
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AIMPOINT Configurations: ENERGY GRIDS All the grids for the aimpoint configurations match the default energy grid of the LETG first order for that detector array; for the HRC-I, the grid corresponds to the LETG/HRC-S first order default grid. Hence, for ACIS configurations, the aimpoint and zeroth order grids all have 8192 points. For HRC, the energy grids include 16384 points. The grids were changed for Cycle 21 in December 2018, to eliminate interpolation errors that occur when comparing spectra (and associated count rates) when comparing or calculating results across configurations.
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ACIS configurations: The only change for ACIS configurations is the ACIS TIME delay qualifier, which has been adjusted for Cycle 27 to be 15 May 2026 UTC, or 895190469.184s MET. The result is that the Cycle 27 EAs for ACIS configurations show a still further decrease in predicted EA below 1 keV compared with Cycle 26 for both ACIS-I and ACIS-S. The relative reduction at the carbon edge is -400%, while at the oxygen K-edge, it is about -1400%.
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HRC-I configurations: The HRC-I QE file set has been upgraded from version N0014 to N0016, with an additional file added effective 2024-09-20T12:00:00, with the new HV setting for HRC-I effective on that date. The change affects all wavelengths, but most significantly below the O K-edge (-3.8%), and to a variable degree +/-10% above 0.6 keV.
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HRC-S configurations: There is only one change in calibration inputs for the HRC-S configurations, specifically the upgrades in the HRC-S QE from version N0016 to N0017, and for the QEU from version N0017 to N0020, and the addition of one extra QE, as well as two new QEU files, the last of which is effective on 2024-09-20T12:00:00. The QE and QEU changes affect all wavelengths, giving an increase from 4%-7% in the PIMMS EAs.
| Configuration | (CHIPX, CHIPY) | ObsID Used | HRMA | QE | QEU | ACIS FI DEAD AREA | ACIS CONTAM | CONTAM TIME DELAY | ACIS OSIP | GREFF | CALDB Filenames |
| ACIS-I |
(970.00, 975.00) (953.74, 958.74) |
9768 | hrmaD1996-12-20axeffaN0008.fits | acisD1997-04-17qeN0006.fits | acisD2010-02-01qeuN0007.fits | acisD1999-09-16dead_areaN0001.fits | acisD1999-08-13contamN0015.fits | 863654469.184 895190469.184 |
N/A | N/A |
acisiD2023-11-20pimmsN0026.fits
acisiD2024-11-06pimmsN0027.fits |
| ACIS-S |
(210.00, 520.00) (193.74, 520.00) |
9300 | hrmaD1996-12-20axeffaN0008.fits | acisD1997-04-17qeN0006.fits | acisD2010-02-01qeuN0007.fits | acisD1999-09-16dead_areaN0001.fits | acisD1999-08-13contamN0015.fits | 863654469.184 895190469.184 |
N/A | N/A |
acissD2023-11-20pimmsN0026.fits
acissD2024-11-06pimmsN0027.fits |
| HRC-I | (7590.0, 7745.0) | 8531 | hrmaD1996-12-20axeffaN0008.fits | hrciD2021-09-04qeN0014.fits hrciD2024-09-20qeN0016.fits |
hrciD1999-07-22qeuN0002.fits | N/A | N/A | N/A | N/A | N/A |
hrciD2023-11-20pimmsN0026.fits
hrciD2024-11-06pimmsN0027.fits |
| HRC-S | (2195.0, 8915.0) | 9630 | hrmaD1996-12-20axeffaN0008.fits | hrcsD2021-05-14qeN0016.fits hrcsD2024-09-20qeN0017.fits |
hrcsD2021-09-02qeuN0017.fits hrcsD2024-09-20qeuN0020.fits |
N/A | N/A | N/A | N/A | N/A |
hrcsD2023-11-20pimmsN0026.fits
hrcsD2024-11-06pimmsN0027.fits |
| HETG0/ACIS-I |
(970.00, 975.00) (953.74, 958.74) |
9768 | hrmaD1996-12-20axeffaN0008.fits | acisD1997-04-17qeN0006.fits | acisD2010-02-01qeuN0007.fits | acisD1999-09-16dead_areaN0001.fits | acisD1999-08-13contamN0015.fits | 863654469.184 895190469.184 |
N/A | hetgD1996-11-01greffpr001N0007.fits |
acisihetg0D2023-11-20pimmsN0026.fits
acisihetg0D2024-11-06pimmsN0027.fits |
| HETG0/ACIS-S |
(210.00, 520.00) (193.74, 520.00) |
7280 | hrmaD1996-12-20axeffaN0008.fits | acisD1997-04-17qeN0006.fits | acisD2010-02-01qeuN0007.fits | acisD1999-09-16dead_areaN0001.fits | acisD1999-08-13contamN0015.fits | 863654469.184 895190469.184 |
N/A | hetgD1996-11-01greffpr001N0007.fits |
acisshetg0D2023-11-20pimmsN0026.fits
acisshetg0D2024-11-06pimmsN0027.fits |
| HEG1/ACIS-S | (211.2, 369.3) | 7280 | hrmaD1996-12-20axeffaN0008.fits | acisD1997-04-17qeN0006.fits | acisD2010-02-01qeuN0007.fits | acisD1999-09-16dead_areaN0001.fits | acisD1999-08-13contamN0015.fits | 863654469.184 895190469.184 |
acisD2000-01-29osip_ctiN0006.fits | hetgD1996-11-01greffpr001N0007.fits |
acissheg1D2023-11-20pimmsN0026.fits
acissheg1D2024-11-06pimmsN0027.fits |
| HEGMEG1/ACIS-S | (211.2, 369.3) | 7280 | hrmaD1996-12-20axeffaN0008.fits | acisD1997-04-17qeN0006.fits | acisD2010-02-01qeuN0007.fits | acisD1999-09-16dead_areaN0001.fits | acisD1999-08-13contamN0015.fits | 863654469.184 895190469.184 |
acisD2000-01-29osip_ctiN0006.fits | hetgD1996-11-01greffpr001N0007.fits |
acisshegmeg1D2023-11-20pimmsN0026.fits
acisshegmeg1D2024-11-06pimmsN0027.fits |
| MEG1/ACIS-S | (211.2, 369.3) | 7280 | hrmaD1996-12-20axeffaN0008.fits | acisD1997-04-17qeN0006.fits | acisD2010-02-01qeuN0007.fits | acisD1999-09-16dead_areaN0001.fits | acisD1999-08-13contamN0015.fits | 863654469.184 895190469.184 |
acisD2000-01-29osip_ctiN0006.fits | hetgD1996-11-01greffpr001N0007.fits |
acissmeg1D2023-11-20pimmsN0026.fits
acissmeg1D2024-11-06pimmsN0027.fits |
| LETG0/ACIS-I |
(970.00, 975.00) (953.74, 958.74) |
9768 | hrmaD1996-12-20axeffaN0008.fits | acisD1997-04-17qeN0006.fits | acisD2010-02-01qeuN0007.fits | acisD1999-09-16dead_areaN0001.fits | acisD1999-08-13contamN0015.fits | 863654469.184 895190469.184 |
N/A | letgD1996-11-01greffpr001N0007.fits |
acisiletg0D2023-11-20pimmsN0026.fits
acisiletg0D2024-11-06pimmsN0027.fits |
| LETG0/ACIS-S | (210.00, 520.00) (193.74, 520.00) |
10662 | hrmaD1996-12-20axeffaN0008.fits | acisD1997-04-17qeN0006.fits | acisD2010-02-01qeuN0007.fits | acisD1999-09-16dead_areaN0001.fits | acisD1999-08-13contamN0015.fits | 863654469.184 895190469.184 |
N/A | letgD1996-11-01greffpr001N0007.fits |
acissletg0D2023-11-20pimmsN0026.fits
acissletg0D2024-11-06pimmsN0027.fits |
| LEG1/ACIS-S | (210.00, 520.00) (193.74, 520.00) |
10662 | hrmaD1996-12-20axeffaN0008.fits | acisD1997-04-17qeN0006.fits | acisD2010-02-01qeuN0007.fits | acisD1999-09-16dead_areaN0001.fits | acisD1999-08-13contamN0015.fits | 863654469.184 895190469.184 |
acisD2000-01-29osip_ctiN0006.fits | letgD1996-11-01greffpr001N0007.fits |
acissleg1D2023-11-20pimmsN0026.fits
acissleg1D2024-11-06pimmsN0027.fits |
| LETG0/HRC-I | (7590.0, 7745.0) | 8531 | hrmaD1996-12-20axeffaN0008.fits | hrciD2021-09-04qeN0014.fits hrciD2024-09-20qeN0016.fits |
hrciD1999-07-22qeuN0002.fits | N/A | N/A | N/A | N/A | letgD1996-11-01greffpr001N0007.fits |
hrciletg0D2023-11-20pimmsN0026.fits
hrciletg0D2024-11-06pimmsN0027.fits |
| LETG0/HRC-S | (2116.9, 8850.3) | 331 | hrmaD1996-12-20axeffaN0008.fits | hrcsD2021-05-14qeN0016.fits hrcsD2024-09-20qeN0017.fits |
hrcsD2021-09-02qeuN0017.fits hrcsD2024-09-20qeuN0020.fits |
N/A | N/A | N/A | N/A | letgD1996-11-01greffpr001N0007.fits |
hrcsletg0D2023-11-20pimmsN0026.fits
hrcsletg0D2024-11-06pimmsN0027.fits |
| LEG1/HRC-S | (2116.9, 8850.3) | 331 | hrmaD1996-12-20axeffaN0008.fits | hrcsD2021-05-14qeN0016.fits hrcsD2024-09-20qeN0017.fits |
hrcsD2021-09-02qeuN0017.fits hrcsD2024-09-20qeuN0020.fits |
N/A | N/A | N/A | N/A | letgD1996-11-01greffpr001N0007.fits |
hrcsleg1D2023-11-20pimmsN0026.fits
hrcsleg1D2024-11-06pimmsN0027.fits |
| LEGHI/HRC-S | (2116.9, 8850.3) | 331 | hrmaD1996-12-20axeffaN0008.fits | hrcsD2021-05-14qeN0016.fits hrcsD2024-09-20qeN0017.fits |
hrcsD2021-09-02qeuN0017.fits hrcsD2024-09-20qeuN0020.fits |
N/A | N/A | N/A | N/A | letgD1996-11-01greffpr001N0007.fits |
hrcsleghiD2023-11-20pimmsN0026.fits
hrcsleghiD2024-11-06pimmsN0027.fits |
Notes for Table 1:
None.