SEARCH FOR GAMMA-RAYS FROM THE UNUSUALLY BRIGHT GRB 130427A WITH THE HAWC GAMMA-RAY OBSERVATORY

Journal Article · Fri Feb 20 00:00:00 EST 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/800/2/78· OSTI ID:22364174

Abeysekara, A. U. ^[1]; Alfaro, R. ^[2]; Alvarez, C.; Arceo, R. ^[3]; Álvarez, J. D.; Arteaga-Velázquez, J. C.; Cotti, U.; De León, C. ^[4]; Solares, H. A. Ayala ^[5]; Barber, A. S. ^[6]; Baughman, B. M.; Braun, J. ^[7]; Bautista-Elivar, N. ^[8]; BenZvi, S. Y. ^[9]; Rosales, M. Bonilla; Carramiñana, A. ^[10]; Caballero-Mora, K. S. ^[11]; Castillo, M.; Cotzomi, J. ^[12]; others, and

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1. Department of Physics and Astronomy, Michigan State University, East Lansing, MI (United States)
2. Instituto de Física, Universidad Nacional Autónoma de México, México D. F. (Mexico)
3. CEFyMAP, Universidad Autónoma de Chiapas, Tuxtla Gutiérrez, Chiapas (Mexico)
4. Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán (Mexico)
5. Department of Physics, Michigan Technological University, Houghton, MI (United States)
6. Department of Physics and Astronomy, University of Utah, Salt Lake City, UT (United States)
7. Department of Physics, University of Maryland, College Park, MD (United States)
8. Universidad Politécnica de Pachuca, Municipio de Zempoala, Hidalgo (Mexico)
9. Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States)
10. Instituto Nacional de Astrofísica, Óptica y Electrónica, Tonantzintla, Puebla (Mexico)
11. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México D. F. (Mexico)
12. Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla (Mexico)

The first limits on the prompt emission from the long gamma-ray burst (GRB) 130427A in the >100 GeV energy band are reported. GRB 130427A was the most powerful burst ever detected with a redshift z ≲ 0.5 and featured the longest lasting emission above 100 MeV. The energy spectrum extends at least up to 95 GeV, clearly in the range observable by the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, a new extensive air shower detector currently under construction in central Mexico. The burst occurred under unfavorable observation conditions, low in the sky and when HAWC was running 10% of the final detector. Based on the observed light curve at MeV-GeV energies, eight different time periods have been searched for prompt and delayed emission from this GRB. In all cases, no statistically significant excess of counts has been found and upper limits have been placed. It is shown that a similar GRB close to zenith would be easily detected by the full HAWC detector, which will be completed soon. The detection rate of the full HAWC detector may be as high as one to two GRBs per year. A detection could provide important information regarding the high energy processes at work and the observation of a possible cut-off beyond the Fermi Large Area Telescope energy range could be the signature of gamma-ray absorption, either in the GRB or along the line of sight due to the extragalactic background light.

• OSTI ID: 22364174
• Journal Information: Astrophysical Journal, Vol. 800, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COSMIC GAMMA BURSTS
DETECTION
DIAGRAMS
ENERGY SPECTRA
EXTENSIVE AIR SHOWERS
GAMMA DETECTION
GAMMA RADIATION
GEV RANGE
MEV RANGE
RED SHIFT
TELESCOPE COUNTERS
VISIBLE RADIATION