The afterglow and kilonova of the short GRB 160821B

GRB 160821B is a short duration gamma-ray burst (GRB) detected and localized by the Neil Gehrels Swift Observatory in the outskirts of a spiral galaxy at z = 0.1613, at a projected physical offset of 16 kpc from the galaxy's center. We present X-ray, optical/nIR, and radio observations of its c...

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Detalhes bibliográficos
Autores: Troja, E., Castro-Tirado, Alberto J., Becerra González, J., Hu, Y., Ryan, G. S., Cenko, S. B., Ricci, R., Novara, G., Sánchez Ramírez, Rubén, Acosta-Pulido, J. A., Ackley, K. D., Caballero Garcia, M. D., Eikenberry, S. S., Guziy, Sergey, Jeong, S., Lien, A. Y., Márquez, Isabel, Pandey, Shashi Bhushan, Park, I. H., Sakamoto, T., Tello, J. C., Sokolov, I., V, Sokolov, Vladimir V., Tiengo, A., Valeev, A. F., Zhang, B. B., Veilleux, S.
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2019
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/194587
Acesso em linha:http://hdl.handle.net/10261/194587
Access Level:acceso abierto
Palavra-chave:Gravitational waves
Nuclear reactions, nucleosynthesis, abundances
Gamma-ray burst: general
Stars: neutron
Descrição
Resumo:GRB 160821B is a short duration gamma-ray burst (GRB) detected and localized by the Neil Gehrels Swift Observatory in the outskirts of a spiral galaxy at z = 0.1613, at a projected physical offset of 16 kpc from the galaxy's center. We present X-ray, optical/nIR, and radio observations of its counterpart and model them with two distinct components of emission: a standard afterglow, arising from the interaction of the relativistic jet with the surrounding medium, and a kilonova, powered by the radioactive decay of the sub-relativistic ejecta. Broadband modelling of the afterglow data reveals a weak reverse shock propagating backward into the jet, and a likely jet-break at 3.5 d. This is consistent with a structured jet seen slightly off-axis (theta(view) similar to theta(core)) while expanding into a low-density medium (n approximate to 10(-3) cm(-3)). Analysis of the kilonova properties suggests a rapid evolution towards red colours, similar to AT2017gfo, and a low-nIR luminosity, possibly due to the presence of a long-lived neutron star. The global properties of the environment, the inferred low mass (M-ej less than or similar to 0.006 M-circle dot) and velocities (v(ej) greater than or similar to 0.05c) of lanthanide-rich ejecta are consistent with a binary neutron star merger progenitor.© 2019 The Authors.

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