Details

Autor(en) / Beteiligte

• Troja, E.
• Castro-Tirado, A. J.
• Gonzalez, J Becerra
• Hu, Y.
• Ryan, G. S.
• Cenko, S. B.
• Ricci, R.
• Novara, G.
• Sanchez-Ramirez, R.
• Acosta-Pulido, J. A.
• Ackley, K. D.
• Garcıa, M. D. Caballero
• Eikenberry, S. S.
• Guziy, S.
• Jeong, S.
• Lien, A. Y.
• Marquez, I.
• Pandey, S. B.
• Park, I. H.
• Sakamoto, T.
• Tello, J. C.
• Sokolov, I. V.
• Tiengo, A.
• Valeev, A. F.
• Zhang, B. B.
• Veilleux, S.

Titel

The Afterglow and Kilonova of the Short GRB 160821B

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2019-08, Vol.489 (2), p.2104-2116

Ort / Verlag

Goddard Space Flight Center: Oxford University Press

Erscheinungsjahr

2019

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• 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 (θview ∼ θcore) while expanding into a low-density medium (n ≈ 10−3 cm−3). Analysis of the kilonova properties suggests a rapid evolution towards red colours, similar toAT2017gfo, 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 (Mej <~ 0.006 Msun) and velocities (vej >~ 0.05c) of lanthanide-rich ejecta are consistent with a binary neutron star merger progenitor.