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NPAC (Nuclear/Particle/Astro/Cosmo) Forum
Cosmic-ray proton measurements with the Fermi-LAT
Date: Thursday, January 19th
Time: 2:30 pm
Place: 5280 Chamberlin Hall
Speaker: David Green, University of Maryland/Goddard
Abstract: The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope has continuously observed the gamma-ray sky since June 2008.
Cosmic-ray protons represent the majority of events downloaded from the Fermi-LAT, which are removed from the gamma-ray dataset. Our sample is comprised of over 1 billion cosmic-ray protons to TeV energies. We present the measurement of the cosmic-ray proton spectrum between 54 GeV and 9.5 TeV using 7 years of Pass 8 flight data from the Fermi-LAT. We developed a dedicated proton event selection with an acceptance of 0.25 m^2 sr. Our analysis yields a large dataset with low statistical uncertainty and low residual contamination for a spectral measurement. The systematic errors associated with the acceptance, energy measurement, GEANT4 Monte-Carlo simulations are an order of magnitude larger than the statistical uncertainty. The event selection and spectral measurement of the proton analysis create the opportunity for additional proton analyses with the Fermi-LAT, such as a dedicated proton anisotropy search.
Host: Stefan Westerhoff
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