2014/06/30 by Stephen K. N. Portillo, Douglas P. Finkbeiner · 1 citation
Mathematics · Physics and Astronomy · #Algorithm #Angular resolution (graph drawing) #Artificial intelligence #Astrophysics #Astrophysics and Cosmic Phenomena #Computer science #Computer vision #Dark Matter and Cosmic Phenomena #Event (particle physics) #Fermi Gamma-ray Space Telescope #Function (biology) #Gamma-ray bursts and supernovae #Geometry #Image (mathematics) #Mathematics #Noise (video) #Optics #Parameter space #Physics #Point (geometry) #Point spread function #Poisson distribution #Quality (philosophy) #Quantum mechanics #Selection (genetic algorithm) #Sky #Statistics #Telescope #astro-ph.HE #astro-ph.IM
paper · pdf · doi:10.1088/0004-637x/796/1/54
published as ApJ 796 (2014) 54 · 6 pages, 6 figures; extended PSF analysis down to 100 MeV, typos corrected; to be published in The Astrophysical Journal
arxiv created 2014/09/29 · openalex publication_date 2014/11/05 · arxiv updated 2014/11/07 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope has a point-spread function (PSF) with large tails, consisting of events affected by tracker inefficiencies, inactive volumes, and hard scattering; these tails can make source confusion a limiting factor. The parameter CTBCORE, available in the publicly available Extended Fermi LAT data (available at http://fermi.gsfc.nasa.gov/ssc/data/access/), estimates the quality of each event's direction reconstruction; by implementing a cut in this parameter, the tails of the PSF can be suppressed at the cost of losing effective area. We implement cuts on CTBCORE and present updated instrument response functions derived from the Fermi LAT data itself, along with all-sky maps generated with these cuts. Having shown the effectiveness of these cuts, especially at low energies, we encourage their use in analyses where angular resolution is more important than Poisson noise.