This code calculates powerful and universal integral upper limits, sensitivities, and times to detection for astroparticle telescopes, assuming the underlying unseen source emission behaves as a power law in energy. All implemented functionality is based on the paper linked in the arxiv.org|astro-PH.HE badge above.
In order to install, use python3 and pip:
pip install git+https://github.com/mahnen/gamma_limits_sensitivity.git
Or clone the repo and run the setup.py from there:
git clone https://github.com/mahnen/gamma_limits_sensitivity.git
cd gamma_limits_sensitivity
pip install .
The repo has been sucessfully used in python2.7 (with some hickups) --- at the moment support is not foreseen.
How it works
There are three main commands that gamma_limits_sensitivity can excecute. These are:
- (ul): calculate integral upper limits
- (sens): calculate sensitivity given an observation time t_obs
- (predict): calculate time to detection, given an uncertain source spectrum (independent normal distributed errors are assumed)
Usage:
gamma_limits_sensitivity ul --l_lim=<arg> --t_obs=<arg> --A_eff=<file> [--E_0=<arg>] [--out=<path>]
gamma_limits_sensitivity sens --s_bg=<arg> --alpha=<arg> --t_obs=<arg> --A_eff=<file> [--E_0=<arg>] [--out=<path>]
gamma_limits_sensitivity predict --s_bg=<arg> --alpha=<arg> --f_0=<arg> --df_0=<arg> --Gamma=<arg> --dGamma=<arg> --E_0=<arg> --A_eff=<file> [--out=<path>]
gamma_limits_sensitivity (-h | --help)
gamma_limits_sensitivity --version
Options:
--l_lim=<arg> Signal count limit, estimated from n_on, n_off, and alpha
--t_obs=<arg> Observation time / s
--A_eff=<file> File with samples from the effective area after all cuts
--out=<path> Optional argument for specifying the output directory
--alpha=<arg> Ratio of On to Off region exposures
--s_bg=<arg> Estimated rate of background in On region / s
--f_0=<arg> Flux normalization / [1/(cm^2 s TeV)]
--df_0=<arg> Error of the flux normalization (1 sigma) / [1/(cm^2 s TeV)]
--Gamma=<arg> Emission power law index (< 0)
--dGamma=<arg> Error of the emission power law index (1 sigma)
--E_0=<arg> Reference energy / TeV
-h --help Show this screen.
--version Show version.
How it also works
In case you want to use gamma_limits_sensitivity in your own python analysis, you can import it and use the member functions directly. The API is the same as for the command line interface:
import gamma_limits_sensitivity as gls
a_eff_file = 'gamma_limits_sensitivity/resources/A_eff/VERITAS_V5_lowZd_McCutcheon.dat'
l_lim = 11.3
t_obs = 25200
result_dict = gls.upper_limit(lambda_lim=l_lim, t_obs=t_obs, a_eff=a_eff_file, e_0=1.)
result_dict['plots']['ul_sensitive_energy'].show()In this case, the resulting plot shown is:
