What Powered the Kilonova-Like Emission After GRB 230307A in the Framework of a Neutron Star-White Dwarf Merger?
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arXiv
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| Autori principali: | , , , , , |
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| Natura: | Preprint |
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2024
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| _version_ | 1866911798323576832 |
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| author | Wang, Xiangyu Ivy Yu, Yun-Wei Ren, Jia Yang, Jun Zou, Ze-Cheng Zhu, Jin-Ping |
| author_facet | Wang, Xiangyu Ivy Yu, Yun-Wei Ren, Jia Yang, Jun Zou, Ze-Cheng Zhu, Jin-Ping |
| contents | The second brightest gamma-ray burst, GRB 230307A (with a duration $T_{90}$ ~ 40 s), exhibited characteristics indicative of a magnetar engine during the prompt emission phase. Notably, a suspected kilonova was identified in its follow-up optical and infrared observations. Here we propose that the origin of GRB 230307A is a neutron star-white dwarf (NS-WD) merger, as this could naturally interpret the long duration and the large physical offset from the center of its host galaxy. In the framework of such a NS-WD merger event, the late-time kilonova-like emission is very likely to be powered by the spin-down of the magnetar and the radioactive decay of $^{56}$Ni, rather than by the decay of r-process elements as these heavy elements may not be easy to be synthesized in a NS-WD merger. It is demonstrated that the above scenario can be supported by our fit to the late-time observational data, where a mass of ~ $10^{-3} \ \rm M_{\odot}$ $^{56}$Ni is involved in the ejecta of a mass of ~ $0.1 \ \rm M_{\odot}$. Particularly, the magnetar parameters required by the fit are consistent with those derived from the early X-ray observation. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_11304 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | What Powered the Kilonova-Like Emission After GRB 230307A in the Framework of a Neutron Star-White Dwarf Merger? Wang, Xiangyu Ivy Yu, Yun-Wei Ren, Jia Yang, Jun Zou, Ze-Cheng Zhu, Jin-Ping High Energy Astrophysical Phenomena The second brightest gamma-ray burst, GRB 230307A (with a duration $T_{90}$ ~ 40 s), exhibited characteristics indicative of a magnetar engine during the prompt emission phase. Notably, a suspected kilonova was identified in its follow-up optical and infrared observations. Here we propose that the origin of GRB 230307A is a neutron star-white dwarf (NS-WD) merger, as this could naturally interpret the long duration and the large physical offset from the center of its host galaxy. In the framework of such a NS-WD merger event, the late-time kilonova-like emission is very likely to be powered by the spin-down of the magnetar and the radioactive decay of $^{56}$Ni, rather than by the decay of r-process elements as these heavy elements may not be easy to be synthesized in a NS-WD merger. It is demonstrated that the above scenario can be supported by our fit to the late-time observational data, where a mass of ~ $10^{-3} \ \rm M_{\odot}$ $^{56}$Ni is involved in the ejecta of a mass of ~ $0.1 \ \rm M_{\odot}$. Particularly, the magnetar parameters required by the fit are consistent with those derived from the early X-ray observation. |
| title | What Powered the Kilonova-Like Emission After GRB 230307A in the Framework of a Neutron Star-White Dwarf Merger? |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2402.11304 |