MAGIC observations of the nearby short gamma-ray burst GRB 160821B
Abstract
The coincident detection of GW170817 in gravitational waves and electromagnetic radiation spanning the radio to MeV gamma-ray bands provided the first direct evidence that short gamma-ray bursts (GRBs) can originate from binary neutron star (BNS) mergers. On the other hand, the properties of short GRBs in high-energy gamma rays are still poorly constrained, with only 20 events detected in the GeV band, and none in the TeV band. GRB~160821B is one of the nearest short GRBs known at . Recent analyses of the multiwavelength observational data of its afterglow emission revealed an optical-infrared kilonova component, characteristic of heavy-element nucleosynthesis in a BNS merger. Aiming to better clarify the nature of short GRBs, this burst was automatically followed up with the MAGIC telescopes, starting from 24 seconds after the burst trigger. Evidence of a gamma-ray signal is found above 0.5 TeV at a significance of during observations that lasted until 4 hours after the burst. Assuming that the observed excess events correspond to gamma-ray emission from GRB 160821B, in conjunction with data at other wavelengths, we investigate its origin in the framework of GRB afterglow models. The simplest interpretation with one-zone models of synchrotron-self-Compton emission from the external forward shock has difficulty accounting for the putative TeV flux. Alternative scenarios are discussed where the TeV emission can be relatively enhanced. The role of future GeV-TeV observations of short GRBs in advancing our understanding of BNS mergers and related topics is briefly addressed.
Keywords
Cite
@article{arxiv.2012.07193,
title = {MAGIC observations of the nearby short gamma-ray burst GRB 160821B},
author = {MAGIC Collaboration and V. A. Acciari and S. Ansoldi and L. A. Antonelli and A. Arbet Engels and K. Asano and D. Baack and A. Babić and A. Baquero and U. Barres de Almeida and J. A. Barrio and J. Becerra González and W. Bednarek and L. Bellizzi and E. Bernardini and M. Bernardos and A. Berti and J. Besenrieder and W. Bhattacharyya and C. Bigongiari and A. Biland and O. Blanch and G. Bonnoli and Ž. Bošnjak and G. Busetto and R. Carosi and G. Ceribella and M. Cerruti and Y. Chai and A. Chilingarian and S. Cikota and S. M. Colak and E. Colombo and J. L. Contreras and J. Cortina and S. Covino and G. D'Amico and V. D'Elia and P. Da Vela and F. Dazzi and A. De Angelis and B. De Lotto and M. Delfino and J. Delgado and C. Delgado Mendez and D. Depaoli and F. Di Pierro and L. Di Venere and E. Do Souto Espiñeira and D. Dominis Prester and A. Donini and D. Dorner and M. Doro and D. Elsaesser and V. Fallah Ramazani and A. Fattorini and G. Ferrara and L. Foffano and M. V. Fonseca and L. Font and C. Fruck and S. Fukami and R. J. García López and M. Garczarczyk and S. Gasparyan and M. Gaug and N. Giglietto and F. Giordano and P. Gliwny and N. Godinović and J. G. Green and D. Green and D. Hadasch and A. Hahn and L. Heckmann and J. Herrera and J. Hoang and D. Hrupec and M. Hütten and T. Inada and S. Inoue and K. Ishio and Y. Iwamura and J. Jormanainen and L. Jouvin and Y. Kajiwara and M. Karjalainen and D. Kerszberg and Y. Kobayashi and H. Kubo and J. Kushida and A. Lamastra and D. Lelas and F. Leone and E. Lindfors and S. Lombardi and F. Longo and R. López-Coto and M. López-Moya and A. López-Oramas and S. Loporchio and B. Machado de Oliveira Fraga and C. Maggio and P. Majumdar and M. Makariev and M. Mallamaci and G. Maneva and M. Manganaro and K. Mannheim and L. Maraschi and M. Mariotti and M. Martínez and D. Mazin and S. Mender and S. Mićanović and D. Miceli and T. Miener and M. Minev and J. M. Miranda and R. Mirzoyan and E. Molina and A. Moralejo and D. Morcuende and V. Moreno and E. Moretti and V. Neustroev and C. Nigro and K. Nilsson and D. Ninci and K. Nishijima and K. Noda and S. Nozaki and Y. Ohtani and T. Oka and J. Otero-Santos and S. Paiano and M. Palatiello and D. Paneque and R. Paoletti and J. M. Paredes and L. Pavletić and P. Peñil and C. Perennes and M. Persic and P. G. Prada Moroni and E. Prandini and C. Priyadarshi and I. Puljak and W. Rhode and M. Ribó and J. Rico and C. Righi and A. Rugliancich and L. Saha and N. Sahakyan and T. Saito and S. Sakurai and K. Satalecka and F. G. Saturni and B. Schleicher and K. Schmidt and T. Schweizer and J. Sitarek and I. Šnidarić and D. Sobczynska and A. Spolon and A. Stamerra and D. Strom and M. Strzys and Y. Suda and T. Surić and M. Takahashi and F. Tavecchio and P. Temnikov and T. Terzić and M. Teshima and N. Torres-Albà and L. Tosti and S. Truzzi and A. Tutone and J. van Scherpenberg and G. Vanzo and M. Vazquez Acosta and S. Ventura and V. Verguilov and C. F. Vigorito and V. Vitale and I. Vovk and M. Will and D. Zarić and L. Nava},
journal= {arXiv preprint arXiv:2012.07193},
year = {2021}
}
Comments
13 pages, 4 figures, Accepted for publication in ApJ. Corresponding authors: K. Noda, L. Nava, and S. Inoue