VERITAS OBSERVATIONS OF GAMMA-RAY BURSTS DETECTED BY SWIFT

Journal Article · Sat Dec 10 04:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/743/1/62· OSTI ID:22004526

Acciari, V A; Benbow, W ^[1]; Aliu, E; Errando, M ^[2]; Arlen, T ^[3]; Aune, T ^[4]; Beilicke, M; Buckley, J H; Bugaev, V ^[5]; Bradbury, S M ^[6]; Byrum, K ^[7]; Cannon, A; Collins-Hughes, E ^[8]; Cesarini, A; Connolly, M P ^[9]; Christiansen, J L ^[10]; Ciupik, L ^[11]; Cui, W ^[12]; Duke, C ^[13]; Falcone, A ^[14] ; others, and

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1. Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States)
2. Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States)
3. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)
4. Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States)
5. Department of Physics, Washington University, St. Louis, MO 63130 (United States)
6. School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT (United Kingdom)
7. Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)
8. School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)
9. School of Physics, National University of Ireland Galway, University Road, Galway (Ireland)
10. Physics Department, California Polytechnic State University, San Luis Obispo, CA 94307 (United States)
11. Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States)
12. Department of Physics, Purdue University, West Lafayette, IN 47907 (United States)
13. Department of Physics, Grinnell College, Grinnell, IA 50112-1690 (United States)
14. Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States)

We present the results of 16 Swift-triggered Gamma-ray burst (GRB) follow-up observations taken with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) telescope array from 2007 January to 2009 June. The median energy threshold and response time of these observations were 260 GeV and 320 s, respectively. Observations had an average duration of 90 minutes. Each burst is analyzed independently in two modes: over the whole duration of the observations and again over a shorter timescale determined by the maximum VERITAS sensitivity to a burst with a t{sup -1.5} time profile. This temporal model is characteristic of GRB afterglows with high-energy, long-lived emission that have been detected by the Large Area Telescope on board the Fermi satellite. No significant very high energy (VHE) gamma-ray emission was detected and upper limits above the VERITAS threshold energy are calculated. The VERITAS upper limits are corrected for gamma-ray extinction by the extragalactic background light and interpreted in the context of the keV emission detected by Swift. For some bursts the VHE emission must have less power than the keV emission, placing constraints on inverse Compton models of VHE emission.

• OSTI ID: 22004526
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 743; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AFTERGLOW
ASTROPHYSICS
COSMIC GAMMA BURSTS
PHOTON EMISSION
SATELLITES
TELESCOPES
THRESHOLD ENERGY