S2 Gbm Intro And Data Access

Software

We use the spectral analysis package rmfit, which was developed for time-resolved analysis of BATSE GRB data but has been adapted for GBM and other instruments with suitable FITS data formats.

The software download and instructions are available at the Fermi Science Support Center. There are binaries, or you can do your own installation. A README_top.txt file will tell you which download is more appropriate for you, but the general guideline is: if you have a Mac you have to do your own installation because static linking of libraries is not permitted, if you have some standard flavor of linux you should be able to use the binaries.

For the self-installation version, there are many pre-requisites (including IDL which you will run for free under a limited license, and the Gnu Scientific Library fortran routines) and system requirements and you should read the additional README file included in the tarball very carefully! It includes all you need to know about downloading external software and the changes you will need to make to your own system.

All software is at:

http://fermi.gsfc.nasa.gov/ssc/data/analysis/user/

Binary:

FGST-rmfit_ver33pr7.tar.gz

Self-install:

FGST_DIY-rmfit_ver33pr7.tar.gz

You will be able to perform spectral analysis of LAT data with rmfit, after using the standard tools gtselect and gtbin to make pha2 files. The format of the pha2 files, however, lacks some information needed by rmfit and we use a python script attached to this page that you can download to your python script area and run to insert that information in the file.

Data Access

All GBM data are in the archive at the Fermi Science Support Center (FSSC). You can retrieve via ftp or using the Browse interface. For this course, you will need all the CSPEC, TTE and RSP files for GRB 090510, and some quicklook lightcurves to aid in detector selection.

FTP

The ftp access root is:

http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers

If you know the complete name of the burst of interest, in this case the year is 2009, and the burst directory is bn090510016 , then navigate to the "current" directory under the main burst directory. Download all the CSPEC, TTE and RSP files. These will have the format:

glg_cspec_dx_bn090510016_vxx.pha
glg_tte_dx_bn090510016_vxx.fit
glg_cspec_dx_bn090510016_vxx.rsp

d is the detector type, b for BGO and n for NaI.
x is the detector number 0,1 for BGO, 0-b for NaI.
xx is the file version number, of which the most current resides in this "current" directory.

In addition to the data files, you will need quicklook lightcurve files.

glg_lc_all_bn090510016_v01.gif

to show you which are the brighter detectors for this burst.

Browse

If you prefer to use the Browse interface, go to :

http://fermi.gsfc.nasa.gov/ssc/data/access/

under "GBM Burst Catalog". Click the top left hand corner to get into Browse.

Search for "GRB090510*" in the "name" field of the table that pops up.
Select your burst 090510016 in the list that is returned, and navigate to the data products using 'Preview and Retrieve'. Select the files described in the FTP section above, or you can retrieve all available data products in a tarball.