Fermi-LAT Binned Analysis

Introduction

This repository contains the main analysis script that was used for the following studies:

1. Dark Matter Interpretation of the Fermi-LAT Observation Toward the Galactic Center (link)

2. Fermi-LAT Observations of Gamma-Ray Emission Toward the Outer Halo of M31 (link)

The module requires installation of the Fermi Science Tools (available here).

The code provided here streamlines the analysis procedure that's detailed in the binned likelihood tutorial (available here). The code is easily generalizable, although it will require some modifications of input directories and files.

Module name:

   analysis_module

Classes:

   1) Analysis: superclass 
   2) Iteration(Analysis) 
   3) PyLikelihood(Iteration,Analysis) 
   4) Plots(Analysis) 

Purpose:

  Perform a binned analysis of the Fermi-LAT data.

Index of Functions:

   Analysis Class(superclass):
           -gtselect()
           -maketime()
           -cmap()
           -ccube()
           -expCube()      
           -expMap()
           -srcMaps(xml_file, outfile)
           -run_gtlike(xml_file, outfile)
           -model_map(src_file, xml_file, outfile, out_type)
           -Residual_map(cmap, model, outfile, operation)
           -Residual_Map2(cmap, model, ccube, modelcube)
           -counts_map_small
           -Make_TS(model_file_xml, xref, yref, nxpix, nypix, bin_size, outfile)
           -gtobsSim(infile, srclist, seed, name)

   Iteration(Analysis):
           -ff_source(source, ff)
           -ff_by_name(root, name_list, ff)
           -iterate(starting_xml_infile, src_file, mass) 

   PyLikelihood(Iteration, Analysis)
           -run_gtlike(src_file, xml_infile, xml_outfile, mass, pass_count)
           
   Plots(Analysis, Iteration)
           -plot_main(x_list, y_list, savefig, Title, x_label, y_label)
           -Counts_spectra_plots()
           -calculate_flux(model_file, exp_file, name, low, high)
           -pylikelihood_flux(src, xml, source_name_list)
           -pylikelihood_counts(input_list, source_plot_list)
           -pyLikelihood_fractional_residuals(src_file,xml_file)

Methodology

   For any given analysis do the following:
   
   1) Define a new directory
   2) Make a parameter card
           -This file defines all the neccessary parameters for the analysis
           -The parameter card must follow the same format as that in parameters.txt
   3) Make a TS file
           -This file contains the point sources to be iterated over
           -The TS file must follow the same format as TS.txt
   4) Make a client code
           -This is a python script that specifies the neccessary functions to be called
           -The file client.py can be used as a template