Kilonova from post-merger ejecta as an optical and near-Infrared counterpart of GW170817

Masaomi Tanaka(National Astronomical Observatory of Japan), Yousuke Utsumi(Hiroshima University), P. A. Mazzali(Max Planck Institute for Astrophysics), Nozomu Tominaga(Konan University), M. Yoshida(National Astronomical Observatory of Japan), Yuichiro Sekiguchi(Toho University), Tomoki Morokuma(The University of Tokyo), Kentaro Motohara(The University of Tokyo), Kouji Ohta(Kyoto University), Koji S. Kawabata(Hiroshima University), Fumio Abe(Nagoya University), Kentaro Aoki(National Astronomical Observatory of Japan), Yuichiro Asakura(Nagoya University), Stefan Baar(University of Hyogo), Sudhanshu Barway(South African Radio Astronomy Observatory), I. A. Bond(Massey University), Mamoru Doi(The University of Tokyo), Takuya Fujiyoshi(National Astronomical Observatory of Japan), Hisanori Furusawa(National Astronomical Observatory of Japan), Satoshi Honda(University of Hyogo), Yoichi Itoh(University of Hyogo), Miho Kawabata(Hiroshima University), N. Kawai(Tokyo Institute of Technology), Ji Hoon Kim(National Astronomical Observatory of Japan), Chien‐Hsiu Lee(National Astronomical Observatory of Japan), Shota Miyazaki(The University of Osaka), Kumiko Morihana(University of Hyogo), Hiroki Nagashima(Hiroshima University), Takahiro Nagayama(Kagoshima University), Tatsuya Nakaoka(Hiroshima University), Fumiaki Nakata(National Astronomical Observatory of Japan), Ryou Ohsawa(The University of Tokyo), Tomohito Ohshima(University of Hyogo), Hirofumi Okita(National Astronomical Observatory of Japan), Tomoki Saito(University of Hyogo), T. Sumi(The University of Osaka), Akito Tajitsu(National Astronomical Observatory of Japan), Jun Takahashi(University of Hyogo), Masaki Takayama(University of Hyogo), Yoichi Tamura(Nagoya University), Ichi Tanaka(National Astronomical Observatory of Japan), Tsuyoshi Terai(National Astronomical Observatory of Japan), P. J. Tristram(University of Canterbury), Naoki Yasuda(Kavli Institute for the Physics and Mathematics of the Universe), Tetsuya Zenko(Kyoto University)
Publications of the Astronomical Society of Japan
October 4, 2017
10.1093/pasj/psx121
Cited by 336Open Access
Full Text

Abstract

Abstract Recent detection of gravitational waves from a neutron star (NS) merger event GW170817 and identification of an electromagnetic counterpart provide a unique opportunity to study the physical processes in NS mergers. To derive properties of ejected material from the NS merger, we perform radiative transfer simulations of kilonova, optical and near-infrared emissions powered by radioactive decays of r-process nuclei synthesized in the merger. We find that the observed near-infrared emission lasting for >10 d is explained by 0.03 M⊙ of ejecta containing lanthanide elements. However, the blue optical component observed at the initial phases requires an ejecta component with a relatively high electron fraction (Ye). We show that both optical and near-infrared emissions are simultaneously reproduced by the ejecta with a medium Ye of ∼0.25. We suggest that a dominant component powering the emission is post-merger ejecta, which exhibits that the mass ejection after the first dynamical ejection is quite efficient. Our results indicate that NS mergers synthesize a wide range of r-process elements and strengthen the hypothesis that NS mergers are the origin of r-process elements in the Universe.

Related Papers

No related papers found

Powered by citation graph analysis