BatAnalysis—A Comprehensive Python Pipeline for Swift BAT Time-tagged Event Data Analysis

Abstract

The Neil Gehrels Swift Observatory (Swift) Burst Alert Telescope (BAT) is a coded aperture gamma-ray instrument with a large field of view that was designed to detect and localize transient events. When a transient is detected, either on board or externally, the BAT saves time-tagged event (TTE) data, which provide the highest-quality information of the locations of the photons on the detector plane and their energies. These data can be used to produce spectra, lightcurves, and sky images of a transient event. While these data products are produced by the Swift Data Center and can be produced by current software, they are often preset to certain time and energy intervals, which have limited their use in the current time domain and multimessenger environment. Here, we introduce a new capability for the BatAnalysis Python package to download and process TTE data under an open-source Python framework that allows for easy interfacing with other Python packages. The new capabilities of the BatAnalysis software allow for TTE data to be used by the community in a variety of advanced customized analyses of astrophysical sources which BAT may have TTE data for, such as fast radio bursts (FRBs), gamma-ray bursts (GRBs), low-mass X-ray binaries (LMXB), soft gamma repeaters, magnetars, and many other sources. We highlight the usefulness of the BatAnalysis package in analyzing TTE data produced by an onboard GRB trigger, an FRB external trigger, a subthreshold detection of the LMXB EXO 0748–676, and an external trigger of a GRB that BAT detected during a slew.