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Here is the distribution of arrival times for the gamma rays from this simulation. Note that during the 20 ks that the source is on, the source is seen on 3 different orbits (with 3 different aspect angles). Also shown are the RA and Dec of the LAT z-axis on the same time scale. The count rates are lower for the first and third orbits because the LAT is pointed further away from the source (which has RA, Dec = 80 deg, 20 deg) and because the source has lower flux at those times.

SpectralTransient (Chiang)

This is a generalization of the TransientTemplate source and allows a broken power-law to specified for the spectrum during each interval. In addition, beginning and end times must be given for each interval, thereby allowing non-uniform interval sizes, as well as zero flux intervals that do no need to be explicitly defined.

Here is an annotated example of an xml-file entry:

   <source name="spectral_transient">
      <spectrum escale="MeV">
<!-- 
     mean flux = 0.1 (1e4/m^2/s) 
     start time = 0 (MET s)
     stop time = 1e4 (MET s)
     template file name = $(GENERICSOURCESROOT)/data/testTemplate.dat
     emin = 20 (MeV, this is the default)
     emax = 2e5 (MeV, default)
     lc # (in FITS file) = 0 (default)
     z (redshift) = 0 (default)
--!>
          <SpectrumClass name="SpectralTransient"
          params="1e-1, 0., 1e4, $(GENERICSOURCESROOT)/data/testTemplate.dat, 20, 2e5, 0, 0"/>
          <celestial_dir ra="193.4" dec="-5.82"/>
      </spectrum>
   </source>

Light curves may be defined using a text file or a FITS file; the latter is convienient for allowing large libraries of light curves to be accessed compactly. The text format files can contain only one light curve. In the case of text files, the "lc #" parameter is ignored. Here is an example light curve text file:

# $Header: /nfs/slac/g/glast/ground/cvs/celestialSources/genericSources/data/testTemplate.dat,v 1.2 2005/02/08 00:20:55 jchiang Exp $
#
# @file testTemplate.dat
# @brief Used by SpectralTransient class
# The columns are
# tstart tstop  flux gamma1 gamma2 ebreak/MeV 
  0.     0.3     50.   1.7   2.5    300.
  0.5    0.8    100.   1.5   2.2    1000.
  0.8    1.0     10.   2.1   2.1    1000.

Lines beginning with a "#" are comments and are ignored.

A description of the FITS file version of the light curve templates is forthcoming. Here is an example that was generated in preparation for the DC2 source model.

PulsarSpectrum (Omodei & Razzano)

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