README File for CALDB 4.7.7 Full Download Instructions 12 Dec 2017 DE Graessle, Chandra CALDB Manager Includes brief Intro, Download instructions, Unpacking instructions, Pointers for further assistance. To learn more about the Chandra CALDB, and to find this information on the WEB, you are referred to http://cxc.harvard.edu/caldb/index.html. For Release Notes to the Chandra CALDB4, and specifically CalDB 4.7.7, see http://cxc.harvard.edu/caldb/downloads/releasenotes.html CalDB 4.7.7 requires CIAO 4.5 (or later version) because of an upgrade to the caldb4 software that was included since the release of CIAO 4.5 in December of 2012. The caldb4 upgrade in question provides for the proper selection of time-displaced CalDB files with overlapping validity date ranges, which does not exist in earlier CIAO versions. CalDB 4.7.7 is optimized for CIAO 4.8 (or later version) which includes an upgrade to the acis_process_events tool (a-p-e) for handling CC-mode observations, specifically to perform the CTI-correction properly for them. As a result, the EDSER SUBPIX algorithm is now applied in a-p-e to CC-modes, where it had not been before. Condensed Release Notes for CalDB 4.7.7 ------------------------------------------------------------------------------------------ I. INTRODUCTION CalDB 4.7.7 is an upgrade to the Chandra CalDB, which includes the following items: HRC-I GMAP for 2017-09-17 HRC-I PIBGSPEC for 2017-09-17 HRC-I BKGRND Event Lists for 2015-2017 PIMMS CYCLE 20 Effective Areas For the CIAO 4.9 / CalDB 4.7.7 release notes see How CalDB 4.7.7 Affects Your Analysis. ------------------------------------------------------------------------------------------ II. SUMMARY OF CHANGES A. HRC-I GMAP for 2017-09-17 Location: $CALDB/data/chandra/hrc/gmap/ Filename: hrciD2017-09-17sampgainN0001.fits The September 2017 adjustment to the HRC-I time-dependent gain map has been calibrated and has been released. The rate of gain decay continues to increase with time; however the HRC calibration team has determined that an annual GMAP adjustment is adequate to maintain approximately 2-4% global accuracy in the gain. The same set of ArLac observations has been used to measure the gain corrections. Details including a plot of the new GMAP and its differences with the previous corrections for 2015 are included in the technical details section of the online CalDB 4.7.7 release notes. As with previous HRC-I GMAP updates, these changes will apply only to recent HRC-I observations, specifically those with DATE-OBS later than 2017-09-17T12:00:00 UTC. See the HRC-I gain map why page for more information. PIPELINES/TOOLS AFFECTED: DS and CIAO level 1 (re)processing tool hrc_process_events Also: CIAO reprocessing script chandra_repro THREADS AFFECTED: Reprocessing Data to Create a New L2 Events File B. HRC-I PIBGSPEC for 2017-09-17 Location: $CALDB/data/chandra/hrc/pibgspec/ Filename: hrciD2017-09-17pibgspecN0001.fits Along with the new 2017 HRC-I GMAP, the incumbent PIBGSPEC for September 2017 is also being released. The PI background spectrum changes with the GMAP, because background events reprocessed using the new GMAP, using the point-source observations as are used to generate the new GMAP. This results in a shift in the background spectrum in channel space relative to the previous spectrum file. Details of how the derivation is done, and a plot of the new spectrum in comparison with previous PIBGSPEC files are given in the technical details section in the CalDB 4.7.7 online release notes. PIPELINES/TOOLS AFFECTED: CIAO tool hrc_bkgrnd_lookup. THREADS AFFECTED: HRC-I Background Spectra Files C. HRC-I BKGRND Event Lists for 2015-2017 Location: $CALDB/data/chandra/hrc/bkgrnd/ Filenames: hrciD2015-01-01bkgrndN0003.fits hrciD2016-01-01bkgrndN0001.fits hrciD2017-01-01bkgrndN0001.fits As per the original HRC Stowed Position Background Study, the CalDB is to be annually updated with HRC-I background event lists effective for one full calendar year. As indicated in the contributed page How to Create a Background Map for an Observation, one updated and two more new HRC-I stowed-position background data sets have been compiled and released to users applicable to calendar years 2015 through 2017, respectively. These have been adapted to CalDB and the applicable CIAO thread for generating fluxed images using the BKGRND files. The "time" columns were removed, the EXPOSURE keywords with appropriate values have been added to the headers, along with the CalDB indexing keywords. These are to be added to the existing 15 annually displaced HRC-I BKGRND files already present in CalDB, which extended from 2000 to 2015 previously. See the HRC-I Background Vignetting why page for more information on use of the HRC-I BKGRND event lists to remove vignetting rings from exposure maps. PIPELINES/TOOLS AFFECTED: CIAO tool reproject_events is used to tailor an appropriate HRC-I BKGRND event list to a give observation. The CIAO script fluximage selects the appropriate BKGRND file from CalDB, and uses it to generate background-subtracted fluxed images. THREADS AFFECTED: The HRC-I Background Event Files HRC-I Exposure Map and Exposure-corrected Image ------------------------------------------------------------------------------- III. Instructions for MANUALLY Downloading and Unpacking CALDB 4.7.7 NOTE: The installation of CalDB 4.7.7 may be done automatically by using the new ciao-install routine, as a matter of course, when installing or upgrading CIAO. See the instruction at "Downloading CIAO ", http://cxc.harvard.edu/ciao/download/ Instructions for Downloading (Manually): Download all files into the same directory, where you intend to install your Chandra CALDB 4.7.7. You will need at least 15 GBytes free to download and unpack the basic structure. The ACIS & HRC background files are now packaged separately, so you don't have to install it to get the basic package. The background files add another 5.2 GB to the space you need. See the following ftp links to acquire the CALDB download tar files for version 4.7.7. MAIN CALDB DIRECTORY AND FILES: 1. ftp://cda.harvard.edu/pub/arcftp/caldb/caldb_4.7.7_main.tar.gz The ACIS and HRC-I background files (blank-field files) are now packaged separately, so if you want to use them you will need files 2 and 3. You need these files if you are going to run reproject_events to generate background files for your ACIS or HRC-I observations. 2. The ACIS BKGRND files tar ball was most recently upgraded with CalDB 4.7.6, 18 Aug 2017 to include version N0002 of the Group G event lists (effective 2012-01-01 through the present.) ftp://cda.harvard.edu/pub/arcftp/caldb/acis_bkgrnd_4.7.6.tar.gz 3. The HRC-I BKGRND files tar ball has been newly upgraded in CalDB 4.7.7 (14 Dec 2017), to include the new background files effective for 2015-2017 calendar years, respectively. ftp://cda.harvard.edu/pub/arcftp/caldb/hrc_bkgrnd_4.7.7.tar.gz TABLE 1: Files and sizes: FILE FILENAME Ship Size(byte) Unpacking space md5sum 1 caldb_4.7.7_main.tar.gz 3,409,517,845 8.3 GB 2643f9791bae129db2782c27ea530c3d 2 acis_bkgrnd_4.7.6.tar.gz 1,387,251,364 2.9 GB 192d4871813c9d5d3e857726195d1261 3 hrc_bkgrnd_4.7.7.tar.gz 2,323,747,030 3.2 GB 3c9b4e5d6966929793d726b12ae4a4b2 Instructions for unpacking: 1. Locate a place for your CALDB. Designate an empty directory to be assigned to the value of $CALDB. Unpack file 1 above from that location. 2. It is not necessary to edit the ./software/tools/caldbinit.* files. When you install or load CIAO, the location of the CalDB gets set up to the appropriate directory. 3. Unpack the ACIS "background" files (File 2 in the table above) if you expect to use them. The files take up a large amount of space. 4. Unpack the HRC "background" files (File 3 in the table above) if you expect to use them. The files take up a large amount of space. 5. Delete the tar files. The latest versions will be maintained online at CXC at all times. -- Chandra CALDB Manager