All-Sky Imaging With Fermi's GBM in the Hard X-ray Regime

ORAL

Abstract

The 12 sodium iodide (NaI) detectors that provide the hard x-ray (8-1000 keV) coverage for the Fermi satellite mission's Gamma-Ray Burst Monitor (GBM) can utilize the Earth Occultation Technique to measure the flux of x-ray and gamma-ray sources. When a source moves behind (or out from behind) the Earth, a step-like feature occurs in the detector count rate. The $ \sim 53$ day orbital precession period allows for complete sky coverage, though the coverage is not uniform. The standard analysis relies on a catalog of known sources for obtaining occultation times and flux measurements. To search for unknown sources, imaging techniques must be used such as the Differential Filter Technique being developed at LSU. A grid with $0.25^{\circ}$ spacing is overlaid on the sky, and the data near a given grid point's occultation times are folded over multiple days. The folded data are then passed through the filter, amplifying an occultation step while damping background and providing an estimate of the intensity from that grid point. Results using GBM will be presented.

–

Authors

  • J. Rodi

    Louisiana State University, Dept. of Physics \& Astronomy, Louisiana State University

  • Philip Adams

    Department of Physics and Astronomy, Louisiana State University, ORNL, UT, ORNL/UT, UK, LSU, Louisiana State University, Zhejiang Normal University, Center for Computation and Technology, Louisiana State University, University of Tuebingen, Germany, Aristotle University of Thessaloniki, Greece, Max Planck Institute for Astrophysics, Max Plank Institute for Astrophysics, Laboratoire d'Astrophysique de Marseille, Albert Einstein Institute, California Institute of Technology, Dept. of Physics \& Astronomy, Louisiana State University, Baton Rouge, LA 70803, Dept. of Physics \& Astronomy, Louisiana State Univ., Baton Rouge, LA 70803, NASA Marshall Space Flight Center, Dept. of Physics \& Astronomy, Louisiana State University, Ohio State University, Wright State University, Department of Physics, North Carolina A\&T State University, Clark Atlanta University, Department of Electrical and Computer Engineering, Pennsylvania State University, University Park, P, Princeton University, University of New Orleans, Alabama A\&M University, Vanderbilt Univ., Konstanz Univ., Isik Univ., Department of Physics, Yale University

  • Philip Adams

    Department of Physics and Astronomy, Louisiana State University, ORNL, UT, ORNL/UT, UK, LSU, Louisiana State University, Zhejiang Normal University, Center for Computation and Technology, Louisiana State University, University of Tuebingen, Germany, Aristotle University of Thessaloniki, Greece, Max Planck Institute for Astrophysics, Max Plank Institute for Astrophysics, Laboratoire d'Astrophysique de Marseille, Albert Einstein Institute, California Institute of Technology, Dept. of Physics \& Astronomy, Louisiana State University, Baton Rouge, LA 70803, Dept. of Physics \& Astronomy, Louisiana State Univ., Baton Rouge, LA 70803, NASA Marshall Space Flight Center, Dept. of Physics \& Astronomy, Louisiana State University, Ohio State University, Wright State University, Department of Physics, North Carolina A\&T State University, Clark Atlanta University, Department of Electrical and Computer Engineering, Pennsylvania State University, University Park, P, Princeton University, University of New Orleans, Alabama A\&M University, Vanderbilt Univ., Konstanz Univ., Isik Univ., Department of Physics, Yale University

  • Philip Adams

    Department of Physics and Astronomy, Louisiana State University, ORNL, UT, ORNL/UT, UK, LSU, Louisiana State University, Zhejiang Normal University, Center for Computation and Technology, Louisiana State University, University of Tuebingen, Germany, Aristotle University of Thessaloniki, Greece, Max Planck Institute for Astrophysics, Max Plank Institute for Astrophysics, Laboratoire d'Astrophysique de Marseille, Albert Einstein Institute, California Institute of Technology, Dept. of Physics \& Astronomy, Louisiana State University, Baton Rouge, LA 70803, Dept. of Physics \& Astronomy, Louisiana State Univ., Baton Rouge, LA 70803, NASA Marshall Space Flight Center, Dept. of Physics \& Astronomy, Louisiana State University, Ohio State University, Wright State University, Department of Physics, North Carolina A\&T State University, Clark Atlanta University, Department of Electrical and Computer Engineering, Pennsylvania State University, University Park, P, Princeton University, University of New Orleans, Alabama A\&M University, Vanderbilt Univ., Konstanz Univ., Isik Univ., Department of Physics, Yale University