like_lc.pl: V1.45 (R. Corbet)
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like_lc.pl

Typing 
like_lc.pl -help 
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Perl script that generates Fermi LAT light curves using 
likelihood analysis. This is not an official part of the Fermi analysis
software.

Caution. The models and other parameters used here
are for demonstration purposes.
You should carefully evaluate the choice of parameters
for your own particular needs!

To use this script you must be set up to 
run both the Fermi science tools and HEASOFT.
This script checks the environment variables LHEASOFT,
PFILES, and FERMI_DIR as a check on this.

In addition, if you are using the auto-generation option to automatically
make a model file from the 2FGL catalog, the environment variable MY_FERMI_DIR
needs to be set. This is where the 2FGL catalog and the
make2FGLxml.py script must be located if used.

The model file generated by make2FGLxml.py uses the parameters
in the 2FGL catalog. In this example only the parameters of the
source of interest are left free, others are held fixed at their
catalog values. Spectra are power laws. This may very well
not be optimum!

Among the inputs prompted for are two files: 
slist.dat
	This should contain a list of source names and their coordinates
	in the form:
	2FGLJ0240.5+6113 40.1317, 61.2281
	i.e. the 2FGL catalog name must be given because if you will use
	make2FGLxml.py to generate the model file.
	Note that there is _no_ space in the source name.
	i.e. "2FGLJ0240.5+6113" rather than "2FGL J0240.5+6113"

Source names should not be duplicated because the output files are
constructed from the source names.

Optionally, an entry in the slist.dat file my have the form:
A_Source 40.1317, 61.2281 super_model.xml
where the 4th entry is the name of the model file to use for that source.
The source name (e.g. "A_Source") must be contained in the model file specified.
	

plist.dat
	This contains a list of photon files, one file per line.
It is also necessary to provide a single spacecraft (FT2) file.

Several temporary files are created while running this script.
At least most are deleted at the end.

The output file for each source is an ASCII file called
XXX_like_lc.dat, where "XXX" is the source name as given in slist.dat
This file contains:
time (bin center, MJD),  flux (cts/cm^2/s), flux error, time bin half width (days), TS value, spectral index, index error

If the spectral model goes not include the parameter "Index" then "-99" is written instead.

Other command line options:

-start mjdstart
	The light curve will start at the specified time in units of MJD.
-stop  mjdstop
	The light curve will end at the specified time in units of MJD.


CHANGES:
1.45	Include spectral output for log parabola and broken power law models. Make default maximum energy 300 GeV,
	allow optional prefix for output light curve name.
1.44	Command line options to specify start and stop times of light curve.
        Minor changes to avoid spurious error messages.
1.43	Support for updated background files for P7REP and use of "CALDB" for IRFs
1.42	Changed name of output xml files to decrease name collision possibility (2014 February)
1.41	Typo correction in prompts (October 2013).
1.4	Support for Pass 7 reprocessed data. (September 2013).
1.35	Change to checks on existence of environment variables.
1.34	Print time step at each loop iteration.
1.33	Changed (yet again) location of diffuse files. (2012 April).
1.32	Change to diffuse models used.
1.31	Bug fix for Pass 6 data.
1.3     Support for Pass 7 data (default) as well as Pass 6. Use 2FGL catalog and make2FGLxml.py.
1.2	Fix for bug causing mangled output if logParabola model was used
1.1	Support for selecting either P6_V3 or P6_V11 IRFs