Constraining weakly interacting massive particles with primordial black holes
Read the paper: arXiv:1905.01238.
Code authors: Adam Coogan, Daniele Gaggero and Bradley Kavanagh.
The figures can be remade with the following commands:
- Figure 1:
- Figure 2:
python plot_frequentist_limits.py -plot_limits
- Figure 3:
python plot_frequentist_limits.py -plot_ps_diff
Computing the point-source limits requires making tables containing
p_gamma, the probability that an individual PBH is detectable by Fermi-LAT. The tables used for the analysis in the paper are contained in the directory
data/p_gammas/. These may take a few hours to recompute. They can be regenerated with
python generate_p_gamma_tables.py -test. With the
-test flag, the
p_gamma tables will be written to
data/p_gammas/test/ instead of overwriting the precomputed tables. The script can also be used to generate
p_gamma tables over different
(m_dm, sv) grids.
All limit calculations require tabulated posteriors of
f_pbh. These are provided in
data/posteriors_f but they can be recomputed by running the script
ComputePosteriors.sh. This script calls a number of scripts in
src/ which calculate the posteriors from gravitational wave observations. Run
python src/tabulate_posteriors_O3.py -h and
python src/tabulate_posteriors_ET.py -h for more detailed usage of these scripts. Scripts for calculating posteriors from SKA will be added shortly.
This branch contains code for performing a Bayesian analysis of the cross section limits.
- The notebook
plot_bayesian_limits.ipynbgenerates Bayesian versions of figures 2 and 3 assuming a uniform prior on the cross section.
submit_posterior_calcs_diff.pygenerates tables of the posterior over a grid of
(m_dm, sv)points for the diffuse analysis. The posterior is very simple: we marginalize over
f, assume the background model for the EGB perfectly matches observations, and simply penalize the extragalactic flux from PBHs for exceeding zero using a Gaussian likelihood for each bin.
- The analysis point-source analysis assumes that astrophysical sources can appear in the unassociated point source catalogue with an unknown rate, which we marginalize over assuming a Jeffreys prior. The script
submit_posterior_calcs_ps.pygenerates tables of
p_gammaand the posterior over an