GCE-2FIG

This code implements the analysis described in 1710.10266 and uses 2FIG sources to constrain the spatial distributions of pulsar-like PS populations. The main purpose of the code is to test the results presented in 1705.00009.

All of the code is contained in the likelihood directory and analysis notebooks are contained in notebooks/.

Authors

• Richard Bartels; richard.t.bartels at gmail dot com
• Dan Hooper; dhooper at fnal dot gov
• Tim Linden; linden.70 at osu dot edu
• Siddharth Mishra-Sharma; smsharma at princeton dot edu
• Nicholas Rodd; nrodd at mit dot edu
• Benjamin Safdi; bsafdi at umich dot edu
• Tracy Slatyer; tslatyer at mit dot edu

Compiling and running

This code package is written in python and cython. To compile the cython, go into the likelihood/ subfolder and execute the file make.sh. Note that you must have cython installed.
Examples of how to run the code are presented in the run/ folder.

Parameter scans

The scripts to run the scans in parallel on the cluster are located in the run/ folder, also containing examples of SLURM batch files used to launch these scan. The file names are below. These are used to obtain the Monte Carlo chains, which are included in the repository in run/chains/.

Three scans are performed, floating:

• ND, z0 and beta (run_nd_z0_beta_prior.py)
• ND, NB, z0 and beta (run_nd_nb_z0_beta_prior.py)
• ND, NB, z0, beta and alpha (run_nd_nb_z0_beta_alpha_prior.py).

The likelihoods of the runs including a bulge population are compared with one without it to test the preference for a bulge population of pulsars. This is analyzed in the notebook Full_Scan.ipynb as described below.

Notebooks

The following notebooks are used in the analysis:

1. Efficiency.ipynb: Constructing of the pulsar detection efficiency for binned data.
2. Sources.ipynb: Constructing the data used in the analysis. The binning scheme is described and data is constructed from a combination of 2FIG candidates and 3FGL sources.
3. Models_and_Likelihoods.ipynb: Deriving the modeled number of disk and bulge sources in each bin. Calculating the likelihood for a given set of disk and bulge model parameters.
4. Full_Scan.ipynb: Analyzing the results of the full parameter scans above, extracting best-fit parameters and TS in preference of a bulge population.
5. A_Resolved_Fraction.ipynb: Calculating the fraction of the GCE that should be resolved for various luminosity functions, including the one calculated in the original 2FIG paper.

Results

The best fit parameters taken from Table 2 of 1705.00009 are given as:

Our runs indicate instead the following best fit parameters:

In particular our returned TS values, whilst still in favor of a bulge population, are more modest. Further we favor different values for both z0 and beta. The derivation of these parameters is shown in the notebooks outlined below.