A First Look at Fermi Tools

A First Look at Fermi Tools : 

A First Look at Fermi Tools Michelle Wojtaszek, University of Wisconsin-Madison COW Fermi Meeting, Wednesday, November 5th, 2008

Fermi GBM : 

Fermi GBM Secondary instrument on the Fermi Gamma-ray Space Telescope 12 + 2 detectors: sodium iodide (NaI) & bismuth germanate (BGO), respectively 10 keV to 30 MeV High time resolution

Currently Available Tools:“gtbin” & “gtbindef” : 

Currently Available Tools:“gtbin” & “gtbindef” Download from Fermi Science support center: http://fermi.gsfc.nasa.gov/ssc/ Full Standard Analysis Environment (SAE) will be released ~ mid-Nov. 2008 (soon…we hope!) Fermi-specific GBM tools-use with other NASA tools (fv, XSPEC, FTOOLS, etc.) Installation (on Mac)-a comedy of errors… More to come….and improvements to be made

Gtbindef : 

Gtbindef Creates input file for gtbin that specifies user defined binning parameters (T or E) Input .txt (ASCII)? output .fits Example: [Astrophysics-iMac:/] michellewojtaszek% gtbindef This is gtbindef version v9r5p6-g1_2 Type of bins, E -- energy or T – time [ ] E File containing the ascii bin definitions[ ] /Users/michellewojtaszek/Astro/evtbin-v9r5p6-g1_2/pfiles/3050.txt Output file name[ ] bin2.fits Units of input energy bins: MeV, GeV, keV, or eV [MeV] [Astrophysics-iMac:/] michellewojtaszek% gtbin

Gtbin : 

Gtbin Used to analyze Fermi data, several important parameter choices, choice of output type, etc. Bins GBM or LAT events list in time, energy, and/or space to produce light curves, spectra, count cubes, or count maps, respectively. Use in combination with other Fermi tools Utilizes a set of general parameters, as well as a set of specific time and energy binning parameters that depend on type of analysis

Primary gtbin commands & parameters : 

Primary gtbin commands & parameters algorithm: CCUBE (a data cube with one or more count maps binned in sky X-Y projected coordinates corresponding to different energy bins) CMAP (count map binned in sky X-Y projected coordinates) LC (light curve binned in time only), PHA1 (spectrum binned in energy) PHA2 (spectra binned in energy for a series of time ranges/bins) evfile: Name of input event FITS file outfile: Name of output FITS file scfile: Spacecraft data file?binning GBM data does not require a ` spacecraft data file; set this parameter to "none".

Fermi GBM Data (filenames/conventions) : 

Fermi GBM Data (filenames/conventions) A multitude of files for GBM: not only a large number of individual files but also many types The names of the Fermi data files contain information regarding their content Familiarity with these is necessary in order to navigate the sheer volume of files containing GBM data, and for proper analysis.

(filenames/conventions) General form: glg_uu_wz_bnyymmddfff_vxx.ttt : 

(filenames/conventions) General form: glg_uu_wz_bnyymmddfff_vxx.ttt glg—The data are from Fermi's GBM uu—The data type wz—Detector type & detector number (or 'all' for catalog files and etc.) bnyymmddfff—The burst number ('bn'), year ('yy'), month ('mm'), day ('dd') fraction of day ('fff') of the GBM trigger. vxx—Version ('v') number xx of the file; the file may be updated, for example as a result of reprocessing. ttt—The extension is usually 'fit' (for FITS) (but can also be pha (binned spectra), rsp—response file, bak—background spectra)

For now, we just want to look at: : 

For now, we just want to look at: Time-Tagged Events (TTE)—lists of the counts in 128 energy channels from each GBM detector for the period of the burst. Catalog entry—An initial catalog file is provided with the other burst data products immediately after the burst, and updates will be provided later.

Making a simple light curve with gtbin: : 

Making a simple light curve with gtbin: Find tcat file, examine contents Ex: glg_tcat_all_bn080925775_v01.fit To determine which detectors were triggered during a particular event, look for “DET_MASK” parameter in header Ex: DET_MASK= '000000110000’?NaI detectors 6 & 7

Running gtbin : 

Running gtbin This is gtbin version v9r5p6-g1_2 Type of output file (CCUBE|CMAP|LC|PHA1|PHA2) [ ] LC Event data file name[ ] /Users/michellewojtaszek/Astro/evtbin-v9r5p6-g1_2/data/2008/bn080925775/current/glg_tte_n7_bn080925775_v01.fit Output file name[ ] trig_7_LC.lc Spacecraft data file name[NONE] Algorithm for defining time bins (FILE|LIN|SNR) [LIN] Start value for first time bin in MET[ ] INDEF Stop value for last time bin in MET[ ] INDEF Width of linearly uniform time bins in MET[ ] .25 Astrophysics-iMac:/] michellewojtaszek%

Plot for glg_tte_n7_bn080925775_v01.fit : 

Plot for glg_tte_n7_bn080925775_v01.fit

More Info: : 

More Info: http://fermi.gsfc.nasa.gov/ssc/ http://polywww.in2p3.fr/activites/physique/glast/workbook/ An online calculator is available to convert between Fermi's MET and other time systems: http://heasarc.gsfc.nasa.gov/cgi-bin/Tools/xTime/xTime.pl