The Emergence of a Lanthanide-rich Kilonova Following the Merger of Two Neutron Stars

Tanvir, NR, Levan, AJ, Gonzalez-Fernandez, C, Korobkin, O, Mandel, I, Rosswog, S, Hjorth, J, D'Avanzo, P, Fruchter, AS, Fryer, CL, Kangas, T, Milvang-Jensen, B, Rosetti, S, Steeghs, D, Wollaeger, RT, Cano, Z, Copperwheat, CM, Covino, S, D'Elia, V, de Ugarte Postigo, A et al (2017) The Emergence of a Lanthanide-rich Kilonova Following the Merger of Two Neutron Stars. Astrophysical Journal Letters, 848 (2). ISSN 2041-8205

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Abstract

We report the discovery and monitoring of the near-infrared counterpart (AT2017gfo) of a binary neutron-star merger event detected as a gravitational wave source by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo (GW170817) and as a short gamma-ray burst by Fermi Gamma-ray Burst Monitor (GBM) and Integral SPI-ACS (GRB 170817A). The evolution of the transient light is consistent with predictions for the behavior of a "kilonova/macronova" powered by the radioactive decay of massive neutron-rich nuclides created via r-process nucleosynthesis in the neutron-star ejecta. In particular, evidence for this scenario is found from broad features seen in Hubble Space Telescope infrared spectroscopy, similar to those predicted for lanthanide-dominated ejecta, and the much slower evolution in the near-infrared ${K}_{{\rm{s}}}$-band compared to the optical. This indicates that the late-time light is dominated by high-opacity lanthanide-rich ejecta, suggesting nucleosynthesis to the third r-process peak (atomic masses $A\approx 195$). This discovery confirms that neutron-star mergers produce kilo-/macronovae and that they are at least a major—if not the dominant—site of rapid neutron capture nucleosynthesis in the universe.

Item Type:	Article
Uncontrolled Keywords:	0201 Astronomical And Space Sciences
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	American Astronomical Society; IOP Publishing
Related URLs:	http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000413099200015&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=7f77ca1697db64ccb27a8011c7ced90d
Date of acceptance:	29 September 2017
Date of first compliant Open Access:	8 November 2017
Date Deposited:	08 Nov 2017 11:17
Last Modified:	04 Sep 2021 11:02
DOI or ID number:	10.3847/2041-8213/aa90b6
URI:	https://ljmu-9.eprints-hosting.org/id/eprint/7488

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