Three dimensional end-to-end simulation for kilonova emission from a black-hole neutron-star merger

Fuente: arXiv
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Autori principali: Kawaguchi, Kyohei, Domoto, Nanae, Fujibayashi, Sho, Hamidani, Hamid, Hayashi, Kota, Shibata, Masaru, Tanaka, Masaomi, Wanajo, Shinya
Natura: Preprint
Pubblicazione: 2024
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author Kawaguchi, Kyohei
Domoto, Nanae
Fujibayashi, Sho
Hamidani, Hamid
Hayashi, Kota
Shibata, Masaru
Tanaka, Masaomi
Wanajo, Shinya
author_facet Kawaguchi, Kyohei
Domoto, Nanae
Fujibayashi, Sho
Hamidani, Hamid
Hayashi, Kota
Shibata, Masaru
Tanaka, Masaomi
Wanajo, Shinya
contents We study long-term evolution of the matter ejected in a black-hole neutron-star (BH-NS) merger employing the results of a long-term numerical-relativity simulation and nucleosynthesis calculation, in which both dynamical and post-merger ejecta formation is consistently followed. In particular, we employ the results for the merger of a $1.35\,M_\odot$ NS and a $5.4\,M_\odot$ BH with the dimensionless spin of 0.75. We confirm the finding in the previous studies that thermal pressure induced by radioactive heating in the ejecta significantly modifies the morphology of the ejecta. We then compute the kilonova (KN) light curves employing the ejecta profile obtained by the long-term evolution. We find that our present BH-NS model results in a KN light curve that is fainter yet more enduring than that observed in AT2017gfo. This is due to the fact that the emission is primarily powered by the lanthanide-rich dynamical ejecta, in which a long photon diffusion time scale is realized by the large mass and high opacity. While the peak brightness of the KN emission in both the optical and near-infrared bands is fainter than or comparable to those of binary NS models, the time-scale maintaining the peak brightness is much longer in the near-infrared band for the BH-NS KN model. Our result indicates that a BH-NS merger with massive ejecta can observationally be identified by the long lasting ($>$two weeks) near-infrared emission.
format Preprint
id arxiv_https___arxiv_org_abs_2404_15027
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Three dimensional end-to-end simulation for kilonova emission from a black-hole neutron-star merger
Kawaguchi, Kyohei
Domoto, Nanae
Fujibayashi, Sho
Hamidani, Hamid
Hayashi, Kota
Shibata, Masaru
Tanaka, Masaomi
Wanajo, Shinya
High Energy Astrophysical Phenomena
General Relativity and Quantum Cosmology
We study long-term evolution of the matter ejected in a black-hole neutron-star (BH-NS) merger employing the results of a long-term numerical-relativity simulation and nucleosynthesis calculation, in which both dynamical and post-merger ejecta formation is consistently followed. In particular, we employ the results for the merger of a $1.35\,M_\odot$ NS and a $5.4\,M_\odot$ BH with the dimensionless spin of 0.75. We confirm the finding in the previous studies that thermal pressure induced by radioactive heating in the ejecta significantly modifies the morphology of the ejecta. We then compute the kilonova (KN) light curves employing the ejecta profile obtained by the long-term evolution. We find that our present BH-NS model results in a KN light curve that is fainter yet more enduring than that observed in AT2017gfo. This is due to the fact that the emission is primarily powered by the lanthanide-rich dynamical ejecta, in which a long photon diffusion time scale is realized by the large mass and high opacity. While the peak brightness of the KN emission in both the optical and near-infrared bands is fainter than or comparable to those of binary NS models, the time-scale maintaining the peak brightness is much longer in the near-infrared band for the BH-NS KN model. Our result indicates that a BH-NS merger with massive ejecta can observationally be identified by the long lasting ($>$two weeks) near-infrared emission.
title Three dimensional end-to-end simulation for kilonova emission from a black-hole neutron-star merger
topic High Energy Astrophysical Phenomena
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2404.15027