Chandra Transmission Grating Data Catalog & Processing Software

TGCat is an archive of Chandra transmission grating spectra, and a suite of software for processing such data.

Data processing for the catalog was done with a suite of ISIS/S-Lang scripts. The software is available for download. These ISIS scripts wrap and call CIAO tools for reprocessing from "Level 1" (acis_process_events or hrc_process_events) through "Level 2" (binned spectra, via tg_resolve_events and tgextract), compute responses (grating "RMFs" and "ARFs", via mkgrmf and mkgarf), and make summary plots.

Documentation for the reprocessing scripts is in this PDF file, which also describes the required software (ISIS, S-Lang modules, CIAO).

Updates:

August 2009:

Problem: Archive download (via download_obsid) would hang. The chandra-get script was modified slightly to support CXC OS upgrades and new ftp defaults.

Problem: S-Lang 2.2 improved error-checking uncovered a bug in aglc.sl (in code not used in tgcat) which prevented the file from loading. Version 1.3.9 fixed this problem.

Enhancements: High-level control of extraction regions added to scripts, particularly for extended source support. See documentation for set_tg_create_mask_info, set_tgextract_info, and run_cfg. Added use of "qualifiers" to run_cfg to handle processing configuration variables.

(Previous version of software and manual.)

Processing Quick Example

See the manual for examples. The top-level, do-it-all case looks like this...

    > download_obsid 16
    > isis
    isis> require( "tgcat" );
    isis> run_cfg( "obs_16" ); % run the pipeline using the instrumental configuration read from a header.
    isis> exit ;
    > display obs_16/summary*.ps &

...and you get a pha file (spectrum), responses (grating ARFs and RMFs), light curves, and quick-look summary plots (like THESE).

Thanks to...

Thanks to Mike Nowak, Dan Dewey, and Arik Mitschang for extensive testing and use of the scripts, and again to Arik Mitschang for the great web interface. Thanks to a number of people for their active interest and participation in the catalog definition and development, especially John Davis, Dan Dewey, John Houck, Herman Marshall, Arik Mitschang, Joy Nichols, Mike Noble, Mike Nowak, and Norbert Schulz. And for behind the scenes work: Craig Anderson, Jen Lauer, Doug Morgan, Beth Sundheim.

Thanks to Claude Canizares for the initial encouragement to work on a catalog and archive.

Feedback:

We want your suggestions, on the interface, on features you would like to see, and on the software. Please email me: dph@space.mit.edu (David Huenemoerder).

This page was last updated Aug 5, 2009 by David P. Huenemoerder. To comment on it or the material presented here, send email to dph@space.mit.edu.