Can fallback accretion on magnetar model power the X-ray flares simultaneously observed with gamma-rays of Gamma-ray bursts?

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Auteurs principaux: Yu, Wen-Yuan, Lü, Hou-Jun, Yang, Xing, Lan, Lin, Yang, Zhe
Format: Preprint
Publié: 2024
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author Yu, Wen-Yuan
Lü, Hou-Jun
Yang, Xing
Lan, Lin
Yang, Zhe
author_facet Yu, Wen-Yuan
Lü, Hou-Jun
Yang, Xing
Lan, Lin
Yang, Zhe
contents The prompt emission, X-ray plateau, and X-ray flares of Gamma-ray bursts (GRB) are thought to be from internal dissipation, and the magnetar as the central engine with propeller fallback accretion is proposed to interpret the observed phenomena of GRBs. In this paper, by systematically searching for X-ray emission observed by Swift/Xry Telescope, we find that seven robust GRBs include both X-ray flares and plateau emissions with measured redshift. More interestingly, the X-ray flares/bumps for those seven GRBs are simultaneously observed in the gamma-ray band. By adopting the propeller fallback accretion model to fit the observed data, it is found that the free parameters of two GRBs (140512A and 180329B) can be constrained very well, while in the other five cases, more or less, they are not all sufficiently constrained. On the other hand, this requires that the conversion efficiency of the propeller is to be two or three times higher than that of the spindown dipole radiation of the magnetar. If this is the case, it is contradictory to the expectation from the propeller model: namely, a dirtier ejecta should be less efficient in producing gamma-ray emissions. Our results hint that at least the magnetar central engine with propeller fallback accretion model cannot interpret very well both the GRB X-ray flares simultaneously observed in the gamma-ray band and the X-ray flares of GRBs with a high Lorentz factor.
format Preprint
id arxiv_https___arxiv_org_abs_2401_04999
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Can fallback accretion on magnetar model power the X-ray flares simultaneously observed with gamma-rays of Gamma-ray bursts?
Yu, Wen-Yuan
Lü, Hou-Jun
Yang, Xing
Lan, Lin
Yang, Zhe
High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
The prompt emission, X-ray plateau, and X-ray flares of Gamma-ray bursts (GRB) are thought to be from internal dissipation, and the magnetar as the central engine with propeller fallback accretion is proposed to interpret the observed phenomena of GRBs. In this paper, by systematically searching for X-ray emission observed by Swift/Xry Telescope, we find that seven robust GRBs include both X-ray flares and plateau emissions with measured redshift. More interestingly, the X-ray flares/bumps for those seven GRBs are simultaneously observed in the gamma-ray band. By adopting the propeller fallback accretion model to fit the observed data, it is found that the free parameters of two GRBs (140512A and 180329B) can be constrained very well, while in the other five cases, more or less, they are not all sufficiently constrained. On the other hand, this requires that the conversion efficiency of the propeller is to be two or three times higher than that of the spindown dipole radiation of the magnetar. If this is the case, it is contradictory to the expectation from the propeller model: namely, a dirtier ejecta should be less efficient in producing gamma-ray emissions. Our results hint that at least the magnetar central engine with propeller fallback accretion model cannot interpret very well both the GRB X-ray flares simultaneously observed in the gamma-ray band and the X-ray flares of GRBs with a high Lorentz factor.
title Can fallback accretion on magnetar model power the X-ray flares simultaneously observed with gamma-rays of Gamma-ray bursts?
topic High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2401.04999