UnmaskedResponder

Python response generator for the Swift Burst Alert Telescope (BAT). Creates full non mask-weighted responses.

In order to build and install this package to your python, first ensure that you're within the /UnmaskedResponder directory. We first want to install our dependencies listed in requirements.txt (using python3 for example):

python -m pip install -r requirements.txt

In the base directory, run the command:

python -m pip install .

Response Files and Configuration

There are many internal data files (mostly used for generating the detector response) used in the codebase. Some are found in this repo and others are found in the Zenodo community.

The simplest way to organize these files is to put all of them into a single directory, and setting the path to that directory as an environment variable named NITRATES_RESP_DIR. If NITRATES_RESP_DIR is set and all of the response files are placed in there with their original file names (and directory structure for tarred directories) then config.py should be able to find the full path to all of the necessary files. NITRATES_RESP_DIR along with other paths can also be hard coded into the config.py file instead of being set as an env variable. If NITRATES_RESP_DIR is not hardcoded and an environmental variable is not set, config.py will assume that NITRATES_RESP_DIR is in the directory above config.py.

In the Zenodo community, the Swift-BAT Response Files for NITRATES dataset contains sevaral .tar.gz files that each contain a folder of data files to be downloaded and extracted into NITRATES_RESP_DIR. The tarred directories: resp_tabs_ebins.tar.gz, comp_flor_resps.tar.gz, hp_flor_resps.tar.gz need to be downloaded and extracted into NITRATES_RESP_DIR, along with the file solid_angle_dpi.npy. The other files either contain more energy bins or are used only for the seeding analyses.

The .tar.gz files in the datasets Swift-BAT Response Files for NITRATES: Forward Ray Tracings at IMX > 0 and Swift-BAT Response Files for NITRATES: Forward Ray Tracings at IMX < 0 also need to be downloaded and extracted into NITRATES_RESP_DIR. These are the forward ray tracing files and are a few hundred GBs uncompressed. They're split up into seperate tarred files do to size limits, but should end up in the same directory, NITRATES_RESP_DIR/ray_traces_detapp_npy/.

The bright_src_cat.fits file and the element_cross_sections folder in this repo should also be copied into NITRATES_RESP_DIR.

Paths to these files can instead be given as arguments to some of the analysis objects, such as Source_Model_InOutFoV().

Important Modules

models.py

• Has the models that convert input paramaters into the count rate expectations for each det and energy bin in the LLH
• The models are sub classes of the Model class
• Currently used diffuse model is Bkg_Model_wFlatA
• Currently used point source model is Source_Model_InOutFoV, which supports both in and out of FoV positions
• Currently used simple point source model for known sources is Point_Source_Model_Binned_Rates
• CompoundModel takes a list of models to make a single model object that can give the total count expectations from all models used

flux_models.py

• Has functions and classes to handle computing fluxes for different flux models
• The different flux model object as subclasses of Flux_Model
  • Flux_Model contains methods to calculate the photon fluxes in a set of photon energy bins
  • Used by the response and point source model objects
• The different available flux models are:
  • Plaw_Flux for a simple power-law
  • Cutoff_Plaw_Flux for a power-law with an exponential cut-off energy
  • Band_Flux for a Band spectrum

response.py

• Contains the functions and objects for the point source model
• Most current response object is ResponseInFoV2 and is used in the Source_Model_InOutFoV model

ray_trace_funcs.py

• Contains the functions and objects to read and perform bilinear interpolation of the foward ray trace images that give the shadowed fraction of detectors at different in FoV sky positions
• RayTraces class manages the reading and interpolation and is used by the point source response function and simple point source model