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

Masaomi Tanaka; Yousuke Utsumi; Paolo A. Mazzali; Nozomu Tominaga; Michitoshi Yoshida; Yuichiro Sekiguchi; Tomoki Morokuma; Kentaro Motohara; Kouji Ohta; Koji S. Kawabata; Fumio Abe; Kentaro Aoki; Yuichiro Asakura; Stefan Baar; Sudhanshu Barway; Ian A. Bond; Mamoru Doi; Takuya Fujiyoshi; Hisanori Furusawa; Satoshi Honda; Yoichi Itoh; Miho Kawabata; Nobuyuki Kawai; Ji Hoon Kim; Chien Hsiu Lee; Shota Miyazaki; Kumiko Morihana; Hiroki Nagashima; Takahiro Nagayama; Tatsuya Nakaoka; Fumiaki Nakata; Ryou Ohsawa; Tomohito Ohshima; Hirofumi Okita; Tomoki Saito; Takahiro Sumi; Akito Tajitsu; Jun Takahashi; Masaki Takayama; Yoichi Tamura; Ichi Tanaka; Tsuyoshi Terai; Paul J. Tristram; Naoki Yasuda; Tetsuya Zenko

doi:10.1093/pasj/psx121

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

Masaomi Tanaka, Yousuke Utsumi, Paolo A. Mazzali, Nozomu Tominaga, Michitoshi Yoshida, Yuichiro Sekiguchi, Tomoki Morokuma, Kentaro Motohara, Kouji Ohta, Koji S. Kawabata, Fumio Abe, Kentaro Aoki, Yuichiro Asakura, Stefan Baar, Sudhanshu Barway, Ian A. Bond, Mamoru Doi, Takuya Fujiyoshi, Hisanori Furusawa, Satoshi HondaYoichi Itoh, Miho Kawabata, Nobuyuki Kawai, Ji Hoon Kim, Chien Hsiu Lee, Shota Miyazaki, Kumiko Morihana, Hiroki Nagashima, Takahiro Nagayama, Tatsuya Nakaoka, Fumiaki Nakata, Ryou Ohsawa, Tomohito Ohshima, Hirofumi Okita, Tomoki Saito, Takahiro Sumi, Akito Tajitsu, Jun Takahashi, Masaki Takayama, Yoichi Tamura, Ichi Tanaka, Tsuyoshi Terai, Paul J. Tristram, Naoki Yasuda, Tetsuya Zenko

SCI - Astronomy

Research output: Contribution to journal › Article › peer-review

235 Citations (Scopus)

Abstract

Recent detection of gravitationalwaves 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 0.03M⊙ 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 (Y_e). We show that both optical and near-infrared emissions are simultaneously reproduced by the ejecta with a medium Y_e 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.

Original language	English
Article number	102
Journal	Publication of the Astronomical Society of Japan
Volume	69
Issue number	6
DOIs	https://doi.org/10.1093/pasj/psx121
Publication status	Published - 2017 Dec 1

Keywords

Abundances
Gravitational waves
Nuclear reactions
Nucleosynthesis
Stars: neutron

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10.1093/pasj/psx121

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Tanaka, M., Utsumi, Y., Mazzali, P. A., Tominaga, N., Yoshida, M., Sekiguchi, Y., Morokuma, T., Motohara, K., Ohta, K., Kawabata, K. S., Abe, F., Aoki, K., Asakura, Y., Baar, S., Barway, S., Bond, I. A., Doi, M., Fujiyoshi, T., Furusawa, H., ... Zenko, T. (2017). Kilonova from post-merger ejecta as an optical and near-Infrared counterpart of GW170817. Publication of the Astronomical Society of Japan, 69(6), Article 102. https://doi.org/10.1093/pasj/psx121

@article{059cd0291a4948ad8883e733f3902473,

title = "Kilonova from post-merger ejecta as an optical and near-Infrared counterpart of GW170817",

abstract = "Recent detection of gravitationalwaves 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 0.03M⊙ 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.",

keywords = "Abundances, Gravitational waves, Nuclear reactions, Nucleosynthesis, Stars: neutron",

author = "Masaomi Tanaka and Yousuke Utsumi and Mazzali, {Paolo A.} and Nozomu Tominaga and Michitoshi Yoshida and Yuichiro Sekiguchi and Tomoki Morokuma and Kentaro Motohara and Kouji Ohta and Kawabata, {Koji S.} and Fumio Abe and Kentaro Aoki and Yuichiro Asakura and Stefan Baar and Sudhanshu Barway and Bond, {Ian A.} and Mamoru Doi and Takuya Fujiyoshi and Hisanori Furusawa and Satoshi Honda and Yoichi Itoh and Miho Kawabata and Nobuyuki Kawai and Kim, {Ji Hoon} and Lee, {Chien Hsiu} and Shota Miyazaki and Kumiko Morihana and Hiroki Nagashima and Takahiro Nagayama and Tatsuya Nakaoka and Fumiaki Nakata and Ryou Ohsawa and Tomohito Ohshima and Hirofumi Okita and Tomoki Saito and Takahiro Sumi and Akito Tajitsu and Jun Takahashi and Masaki Takayama and Yoichi Tamura and Ichi Tanaka and Tsuyoshi Terai and Tristram, {Paul J.} and Naoki Yasuda and Tetsuya Zenko",

note = "Funding Information: We thank Kenta Hotokezaka and Shinya Wanajo for fruitful discussion. Numerical simulations were carried out on the Cray XC30 at the Center for Computational Astrophysics, National Astronomical Observatory of Japan. This research was supported by the NINS program for cross-disciplinary science study, Inoue Science Research Award from Inoue Foundation for Science, the research grant program of the Toyota Foundation (D11-R-0830), the natural science grant of the Mitsubishi Foundation, the research grant of the Yamada Science Foundation, the MEXT KAKENHI ( JP17H06363, JP15H00788, JP24103003, JP10147207, JP10147214), and JSPS KAKENHI (JP16H02183, JP15H02075, JP25800103, JP26800103). The IRSF project is a collaboration between Nagoya University and the South African Astronomical Observatory (SAAO) supported by Optical & Near-Infrared Astronomy Inter-University Cooperation Program from MEXT of Japan and the National Research Foundation (NRF) of South Africa. Publisher Copyright: {\textcopyright} The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan.",

year = "2017",

month = dec,

day = "1",

doi = "10.1093/pasj/psx121",

language = "English",

volume = "69",

journal = "Publication of the Astronomical Society of Japan",

issn = "0004-6264",

publisher = "Oxford University Press",

number = "6",

}

Tanaka, M, Utsumi, Y, Mazzali, PA, Tominaga, N, Yoshida, M, Sekiguchi, Y, Morokuma, T, Motohara, K, Ohta, K, Kawabata, KS, Abe, F, Aoki, K, Asakura, Y, Baar, S, Barway, S, Bond, IA, Doi, M, Fujiyoshi, T, Furusawa, H, Honda, S, Itoh, Y, Kawabata, M, Kawai, N, Kim, JH, Lee, CH, Miyazaki, S, Morihana, K, Nagashima, H, Nagayama, T, Nakaoka, T, Nakata, F, Ohsawa, R, Ohshima, T, Okita, H, Saito, T, Sumi, T, Tajitsu, A, Takahashi, J, Takayama, M, Tamura, Y, Tanaka, I, Terai, T, Tristram, PJ, Yasuda, N & Zenko, T 2017, 'Kilonova from post-merger ejecta as an optical and near-Infrared counterpart of GW170817', Publication of the Astronomical Society of Japan, vol. 69, no. 6, 102. https://doi.org/10.1093/pasj/psx121

TY - JOUR

T1 - Kilonova from post-merger ejecta as an optical and near-Infrared counterpart of GW170817

AU - Tanaka, Masaomi

AU - Utsumi, Yousuke

AU - Mazzali, Paolo A.

AU - Tominaga, Nozomu

AU - Yoshida, Michitoshi

AU - Sekiguchi, Yuichiro

AU - Morokuma, Tomoki

AU - Motohara, Kentaro

AU - Ohta, Kouji

AU - Kawabata, Koji S.

AU - Abe, Fumio

AU - Aoki, Kentaro

AU - Asakura, Yuichiro

AU - Baar, Stefan

AU - Barway, Sudhanshu

AU - Bond, Ian A.

AU - Doi, Mamoru

AU - Fujiyoshi, Takuya

AU - Furusawa, Hisanori

AU - Honda, Satoshi

AU - Itoh, Yoichi

AU - Kawabata, Miho

AU - Kawai, Nobuyuki

AU - Kim, Ji Hoon

AU - Lee, Chien Hsiu

AU - Miyazaki, Shota

AU - Morihana, Kumiko

AU - Nagashima, Hiroki

AU - Nagayama, Takahiro

AU - Nakaoka, Tatsuya

AU - Nakata, Fumiaki

AU - Ohsawa, Ryou

AU - Ohshima, Tomohito

AU - Okita, Hirofumi

AU - Saito, Tomoki

AU - Sumi, Takahiro

AU - Tajitsu, Akito

AU - Takahashi, Jun

AU - Takayama, Masaki

AU - Tamura, Yoichi

AU - Tanaka, Ichi

AU - Terai, Tsuyoshi

AU - Tristram, Paul J.

AU - Yasuda, Naoki

AU - Zenko, Tetsuya

N1 - Funding Information: We thank Kenta Hotokezaka and Shinya Wanajo for fruitful discussion. Numerical simulations were carried out on the Cray XC30 at the Center for Computational Astrophysics, National Astronomical Observatory of Japan. This research was supported by the NINS program for cross-disciplinary science study, Inoue Science Research Award from Inoue Foundation for Science, the research grant program of the Toyota Foundation (D11-R-0830), the natural science grant of the Mitsubishi Foundation, the research grant of the Yamada Science Foundation, the MEXT KAKENHI ( JP17H06363, JP15H00788, JP24103003, JP10147207, JP10147214), and JSPS KAKENHI (JP16H02183, JP15H02075, JP25800103, JP26800103). The IRSF project is a collaboration between Nagoya University and the South African Astronomical Observatory (SAAO) supported by Optical & Near-Infrared Astronomy Inter-University Cooperation Program from MEXT of Japan and the National Research Foundation (NRF) of South Africa. Publisher Copyright: © The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan.

PY - 2017/12/1

Y1 - 2017/12/1

N2 - Recent detection of gravitationalwaves 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 0.03M⊙ 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.

AB - Recent detection of gravitationalwaves 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 0.03M⊙ 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.

KW - Abundances

KW - Gravitational waves

KW - Nuclear reactions

KW - Nucleosynthesis

KW - Stars: neutron

UR - http://www.scopus.com/inward/record.url?scp=85052004176&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85052004176&partnerID=8YFLogxK

U2 - 10.1093/pasj/psx121

DO - 10.1093/pasj/psx121

M3 - Article

AN - SCOPUS:85052004176

SN - 0004-6264

VL - 69

JO - Publication of the Astronomical Society of Japan

JF - Publication of the Astronomical Society of Japan

IS - 6

M1 - 102

ER -

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

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