GRB 211211A的GeV辐射

GRB 211211A的GeV辐射

两个小组都处理了数据

GeV emission from a compact binary merger

Alessio Mei, Biswajit Banerjee, Gor Oganesyan, Om Sharan Salafia, Stefano Giarratana, Marica Branchesi, Paolo D'Avanzo, Sergio Campana, Giancarlo Ghirlanda, Samuele Ronchini, Amit Shukla, Pawan Tiwari

An energetic γ-ray burst (GRB), GRB 211211A, was observed on 2021 December 11 by the Neil Gehrels Swift Observatory. Despite its long duration, typically associated with bursts produced by the collapse of massive stars, the discovery of an optical-infrared kilonova and a quasi-periodic oscillation during a gamma-ray precursor points to a compact object binary merger origin. The complete understanding of this nearby (∼ 1 billion light-years) burst will significantly impact our knowledge of GRB progenitors and the physical processes that lead to electromagnetic emission in compact binary mergers. Here, we report the discovery of a significant (>5σ) transient-like emission in the high-energy γ-rays (HE; E>0.1 GeV) observed by Fermi/LAT starting at 103 s after the burst. After an initial phase with a roughly constant flux (∼5×10−10 erg s−1 cm−2) lasting ∼2×104 s, the flux started decreasing and soon went undetected. The multi-wavelength afterglow emission observed at such late times is usually in good agreement with synchrotron emission from a relativistic shock wave that arises as the GRB jet decelerates in the interstellar medium. However, our detailed modelling of a rich dataset comprising public and dedicated multi-wavelength observations demonstrates that GeV emission from GRB 211211A is in excess with respect to the expectation of this scenario. We explore the possibility that the GeV excess is inverse Compton emission due to the interaction of a long-lived, low-power jet with an external source of photons. We discover that the kilonova emission can provide the necessary seed photons for GeV emission in binary neutron star mergers.

Subjects:	High Energy Astrophysical Phenomena (astro-ph.HE)
Cite as:	arXiv:2205.08566 [astro-ph.HE]
	(or arXiv:2205.08566v1 [astro-ph.HE] for this version) 来源： https://arxiv.org/abs/2205.08566

和别的暴放一起， 也貌似不太特殊啊。 而且还有红色的呢（来自短暴的GeV辐射）

第二天的另一篇文章

Fermi-LAT detection of a GeV afterglow from a compact stellar merger

Hai-Ming Zhang, Yi-Yun Huang, Jian-He Zheng, Ruo-Yu Liu, Xiang-Yu Wang

Comments: 1 table, 3 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

It is usually thought that long-duration gamma-ray bursts (GRBs) are associated with massive star core collapse whereas short-duration GRBs are associated with mergers of compact stellar binaries. The discovery of a kilonova associated with a nearby (350 Mpc) long-duration GRB- GRB 211211A, however, indicates that the progenitor of this long-duration GRB is a compact object merger. Here we report the \emph{Fermi}-LAT detection of gamma-ray (>100 MeV) afterglow emission from GRB 211211A, which lasts ∼20000 s after the burst, the longest event for conventional short-duration GRBs ever detected. We suggest that this gamma-ray emission results mainly from afterglow synchrotron emission. The soft spectrum of GeV emission may arise from a limited maximum synchrotron energy of only a few hundreds of MeV at ∼20000 s. The usually long duration of the GeV emission could be due to the proximity of this GRB and the long deceleration time of the GRB jet that is expanding in a low density cricumburst medium, consistent with the compact stellar merger scenario.

来源： https://arxiv.org/list/astro-ph/new

普通同步+SSC辐射即可解释GeV的辐射。

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