Galactic latitude and Source Cuts

Galactic latitude selections

Once good Fermi data in the desired energy range is selected, we proceed to narrow our focus on photons with galactic latitude b above 50deg or below -50deg. The following Python script accomplishes this goal: Media:bcut.py. After running this script on each of the files obtained from noroi.sh, we obtain the following datafiles containing photons only in the polar caps Media:bcutoutput.tar.gz

Removing regions around Fermi sources (Ferrer)

We use the First Fermi-LAT Catalog of Sources above 10 GeV (1FHL). (Note that this is not the 1st-year Fermi catalogue, and it is actually more recent than the 2nd-year Point Source catalogue. See the link for a description).

The following Python script takes the data within the polar caps selected above and discards any photon therein that falls within a circular region of radius 1.5deg centered at the position of any source listed in the 1FHL catalogue. Media:nosource.py. The result of running this script on the files obtained after bcut.py can be found here Media:nosourceoutput.tar.gz.

Removing regions around Fermi sources (Chen)

Here are the Chen’s IDL routines to accomplish those two goals above: File:Mask 1FHL.tar. These routines read the filtered weekly files generated by Chen’s Bash script in section Fermi data. These routines combine the weekly files, filter the events by galactic latitude criterion, and mask out 1FHL sources. The resulting lists of photon events are the same as those in Media:nosourceoutput.tar.gz (we have checked that they have the same EVENT_ID value).