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Volume 312 - 7th International Fermi Symposium (IFS2017) - Session Other Transients
MAGIC observation of the short nearby GRB160821B
M. Palatiello, K. Noda, S. Inoue, P. Colin, E. Moretti, F. Longo* on behalf of the MAGIC and Fermi Collaboration
*corresponding author
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Supplementary files
Published on: 2017 December 12
Abstract
Gamma-ray bursts (GRBs) are the most luminous explosions in the Universe, yet many of their basic properties remain poorly understood, particularly for short GRBs with durations less than ~ 2 sec. Fermi/LAT has shown that some GRBs emit at high-energy (100 MeV to ~ 100 GeV) gamma-rays with a hard (index of < 2) spectrum. Atmospheric Cherenkov Telescopes (IACTs) could provide information on the possible emission at very-high-energy (VHE, > 100 GeV) gamma-rays. In particular MAGIC telescopes were designed to explore this particular physics case. Although no firm detection has been reported so far, the MAGIC Collaboration reported a hint of a VHE gamma-ray emissions from a short, very nearby (z = 0.16) GRB 160821B. Even if it is only a hint, this creates doubts on the the standard expectations for gamma-ray emissions from GRBs: low energy (~ 30 GeV) over a short period (< 100 s). Moreover GRB 160821B showed a clear extended emission in the X-ray band, which can be generated by a ms pulsar after a NS-NS or NS-BH merger. In this picture a long activity with multiple Lorenz factors is well expected, which can consistently explain a possible long VHE emission. In this contribution we will briefly report on the hint of the signal and on possible interpretations of the data assuming that the hint is real.
DOI: https://doi.org/10.22323/1.312.0084
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