README File for CALDB 4.8.5 Full Download Instructions 07 NOV 2019 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 4.8.5, see http://cxc.harvard.edu/caldb/downloads/releasenotes.html Condensed Release Notes for CalDB 4.8.5 ------------------------------------------------------------------------------------------ I. Introduction CalDB 4.8.5 is an upgrade to the Chandra CalDB, which includes the following items: * ACIS CONTAM version N0013 For the CIAO 4.11 / CalDB 4.8.5 release notes see How CalDB 4.8.5 Affects Your Analysis, at http://cxc.harvard.edu/ciao/releasenotes/ciao_4.11_release.html#HowCALDB4.8.5AffectsYourAnalysis ------------------------------------------------------------------------------------------ II. SUMMARY OF CHANGES Location: $CALDB/data/chandra/acis/contam/ Filename: acisD1999-08-13contamN0013.fits Analysis of recent observations of previously-observed cosmic sources, such as certain clusters of galaxies and supernova remnants, have resulted in unexpected increased temperatures and reduced flux levels that have been traced to a deviation of the ACIS contaminant model (CONTAM in CalDB) from calibration measurements. Hence it is time to update this model, specifically to improve its performance since about 2018 for center-array optical depths and for center-to-edge spatial modeling since about 2015. More specifically, the new model specifies a linear layer depth with time since 2016, as well as a linear center-to-edge dependence with time since around 2010-2011. The current and new models are compared with calibration data in the technical details section below. See the why page for more general information on the ACIS OBF contaminant. CIAO SCRIPTS/TOOLS AFFECTED: See the script fluximage, which uses mkinstmap See the script specextract, which uses mkwarf See the script 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 ------------------------------------------------------------------------------- III. Instructions for MANUALLY Downloading and Unpacking CALDB 4.8.5 NOTE: The installation of CalDB 4.8.5 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 4.8.5. You will need at least 20 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 6.1 GB to the space you need. See the following ftp links to acquire the CALDB download tar files for version 4.8.5. MAIN CALDB DIRECTORY AND FILES: 1. ftp://cda.harvard.edu/pub/arcftp/caldb/caldb_4.8.5_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_4.8.5_main.tar.gz 3,636,134,097 8.2 GB 4e2f3238b1adadea093fe19401867087 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