All-Sky Imaging of the Gamma-Ray Sky with BATSE

ORAL

Abstract

Earth occultation provides a means of monitoring gamma-ray sources over the entire sky. The technique has been demonstrated with the Burst And Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO), and is now being used with the Gamma-ray Burst Monitor (GBM) instrument on the Fermi mission. Although the approach provides a powerful wide-field monitoring capability, the BATSE and GBM implementations of the technique have so far limited the analysis to a catalog of previously identified sources. We present an indirect imaging method that permits searching for unknown sources by applying the Differential Filter Technique (DFT) to archival BATSE data. Occultation steps are transformed into gaussian-like features corresponding to the intensities measured from each pixel in the sky. Coupling this to the $ \sim 51$-day precession cycle of the CGRO orbit (with $28.5^{\circ}$ inclination) makes it possible to perform an all-sky survey. By applying standard imaging deconvolution techniques, it becomes possible to locate known and unknown sources with spatial resolution to $\sim 0.5^{\circ}$ accuracy. Initial results from the application of the approach to BATSE will be presented.

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Authors

  • Y. Zhang

    Dept. of Physics \& Astronomy, Louisiana State Univ., Baton Rouge, LA 70803

  • 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