Toward an Enhanced BATSE Gamma-Ray Burst Catalog

The Compton Gamma Ray Observatory (CGRO) ceased operation and was de-orbited in 2000, passing the baton for twenty-first century gamma-ray burst (GRB) surveying from CGRO's Burst and Transient Source Experiment (BATSE) to Swift, and Fermi's Gamma-ray Burst Monitor (GBM) (and a few smaller missions). But the Swift and Fermi instruments were not designed with the goals of producing a large, well-characterized GRB catalog, and they will detect far fewer GRBs during their lifetimes than BATSE did. The BATSE burst catalog will remain the key observational resource for addressing GRB population studies for a decade or more. Yet well under half of BATSE GRBs may be used for population studies, due to incomplete characterization of important aspects of the BATSE survey. We describe ongoing work aiming to characterize the full 5B BATSE GRB sample by calculating accurate exposure maps and efficiency functions for the sample. We describe the key elements of our calculations (including treatment of atmospheric scattering and statistical effects), and present new exposure maps for the 5B catalog. This work is supported by NASA's Astrophysics Data Analysis Program (ADP).