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Title: Short GRB 130603B: Discovery of a jet break in the optical and radio afterglows, and a mysterious late-time X-ray excess

We present radio, optical/NIR, and X-ray observations of the afterglow of the short-duration Swift and Konus-Wind GRB 130603B, and uncover a break in the radio and optical bands at ≈0.5 day after the burst, best explained as a jet break with an inferred jet opening angle of ≈4°-8°. GRB 130603B is only the third short GRB with a radio afterglow detection to date, and represents the first time that a jet break has been evident in the radio band. We model the temporal evolution of the spectral energy distribution to determine the burst explosion properties and find an isotropic-equivalent kinetic energy of ≈(0.6-1.7) × 10{sup 51} erg and a circumburst density of ≈5 × 10{sup –3}-30 cm{sup –3}. From the inferred opening angle of GRB 130603B, we calculate beaming-corrected energies of E {sub γ} ≈ (0.5-2) × 10{sup 49} erg and E {sub K} ≈ (0.1-1.6) × 10{sup 49} erg. Along with previous measurements and lower limits we find a median opening angle of ≈10°. Using the all-sky observed rate of 10 Gpc{sup –3} yr{sup –1}, this implies a true short GRB rate of ≈20 yr{sup –1} within 200 Mpc, the Advanced LIGO/VIRGO sensitivity range for neutron star binary mergers.more » Finally, we uncover evidence for significant excess emission in the X-ray afterglow of GRB 130603B at ≳ 1 day and conclude that the additional energy component could be due to fall-back accretion or spin-down energy from a magnetar formed following the merger.« less
Authors:
; ; ; ; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ; ;  [5] ; ;  [6] ;  [7]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  2. Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)
  3. Astronomy Department, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801 (United States)
  4. School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287-1404 (United States)
  5. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
  6. Pomona College, 610 N. College Ave., Claremont, CA 91711 (United States)
  7. Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106-7215 (United States)
Publication Date:
OSTI Identifier:
22348272
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AFTERGLOW; COSMIC GAMMA BURSTS; DENSITY; DETECTION; EMISSION; ENERGY SPECTRA; EVOLUTION; EXPLOSIONS; NEAR INFRARED RADIATION; NEUTRON STARS; RADIO TELESCOPES; SENSITIVITY; SPIN; VISIBLE RADIATION; X RADIATION