aperture.pl: V1.53 (R. Corbet)
-help

aperture.pl 

Typing
$ aperture.pl -help
will display this help information.

This is a Perl script that generates Fermi LAT light curves using
aperture photometry. This is not an official part of the Fermi
analysis software.

To use the script you can either type:
$ perl aperture.pl
or
you can make the file executable (e.g. chmod +x aperture.pl) and edit
the first line of this script to point at your local installation of
perl.

The default value of parameters may be optionally taken from a file.
e.g.
$ aperture.pl -file aperture.par

The script can be run in non-interactive mode where parameter values
will not be prompted for using the "-batch" flag. This
can be combined with the "-file" option.
e.g.
$ aperture.pl -batch -file aperture.par

To generate a parameter file use:
$ aperture.pl -makepar [filename]
If no file name is specififed, a file called "aperture.par" will be created.

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.


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
        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.


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.


One output file is produced for each source in the slist.dat file.
The file has the name of the source with "lc_" prepended and ".out" appended.
e.g. lc_2FGLJ0240.5+6113.out

Each output file has the format:
Time (MJD), count rate (cts/cm2/s), count-rate based error (cts/cm2/s), bin half width (days), exposure-based error (cts/cm2/s), exposure (cm^2 s)

For many purposes the exposure-based error is recommended.

The count-rate based errors use the prescription of the BaBar
Statistics Working Group.
http://www-cdf.fnal.gov/physics/statistics/notes/pois_eb.txt The
asymmetric errors from this prescription are then "symmeterized" to
produce a single number.

Both the exposure-based and count-rate based errors will give non-zero
errors, even if no photons are detected in a time bin.

-version
	Print version number of script then exit.
-batch
	Runs with minimal output and no prompting for inputs.
-makepar [filename]
	Generates a default parameter file with the name [filename]. If no name
	is given the file generated is like_lc.par
-file [filename]
	Reads parameter values from a file with the name [filename].
-start [start time in MJD]
	Specify start time for light curve in Modified Julian Day.
-stop [stop time in MJD]
	Specify end time for light curve in Modified Julian Day.


History:
V1.53	- bug fix (missing routines)
V1.52	- add start and stop command line options
V1.51	- updated help information
V1.5	- Pass 8 support added (default)
V1.42	- correction to flux units in help information
V1.41	- minor changes. Change default energy upper limit to 300 GeV
V1.4	- add Pass7 reprocessed option
V1.31	- add "-makepar" option
V1.3	- add "-batch" and "-file" options
V1.21	- change default to _not_ barycenter times
V1.2	- change to checks on whether needed environment variables are set.
V1.1	- remove calls to sunpos and increase Sun avoidance defaults now that
solar position is given in spacecraft files.
V1.0	- initial release