High energy emission of GRB 130821A: Constraining the density profile of the circum-burst medium as well as the initial Lorentz factor of the outflow

Journal Article · Sat Feb 01 00:00:00 EST 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/781/2/74· OSTI ID:22348125

Liang, Yun-Feng; Zhou, Bei; He, Hao-Ning; Fan, Yi-Zhong; Wei, Da-Ming ^[1]

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1. Key laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

GRB 130821A was detected by Fermi-GBM/LAT, Konus-WIND, SPI-ACS/INTEGRAL, RHESSI and Mars Odyssey-HEND. Although the data of GRB 130821A are very limited, we show in this work that the high energy γ-ray emission (i.e., above 100 MeV) alone imposes tight constraint on the density profile of the circum-burst medium as well as the initial Lorentz factor of the outflow. The temporal behavior of the high energy γ-ray emission is consistent with the forward shock synchrotron radiation model, and the circum-burst medium likely has a constant-density profile. The Lorentz factor is about a few hundred, similar to other bright GRBs.

• OSTI ID: 22348125
• Journal Information: Astrophysical Journal, Vol. 781, 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
DENSITY
EMISSION
GAMMA RADIATION
LIMITING VALUES
MARS PLANET
MEV RANGE
SYNCHROTRON RADIATION