GRB 170817A Associated with GW170817: Multi-frequency Observations and Modeling of Prompt Gamma-Ray Emission
GRB 170817A Associated with GW170817: Multi-frequency Observations and Modeling of Prompt Gamma-Ray Emission
复制标题
DOI：
10.3847/2041-8213/aaa2f6
复制
发表时间：
2017-10
期刊：
影响因子：
--
通讯作者：
A. Pozanenko;M. Barkov;P. Minaev;A. Volnova;E. Mazaeva;A. Moskvitin;M. Krugov;V. Samodurov;V. Loznikov;M. Lyutikov
中科院分区：
文献类型：
--
作者：
A. Pozanenko;M. Barkov;P. Minaev;A. Volnova;E. Mazaeva;A. Moskvitin;M. Krugov;V. Samodurov;V. Loznikov;M. Lyutikov
利用Chilescope天文台的光学望远镜和Pushchino射电天文台的大扫描天线（BSA）在110 MHz上对GW 170817/GRB 170817 A的电磁瞬变进行了观测。Chilescope天文台在第三天在NGC 4993星系的外围探测到了一个1.19亿米的光学瞬变;我们在它迅速减少后继续观测。我们对任何持续时间为10-60 s的射电源提出了1.5 × 104 Jy的上限，它可能与GW 170817/GRB 170817 A有关。瞬发伽马射线发射由两个不同的组成部分-一个硬短脉冲相对于LIGO信号延迟了102 s，而较软的热脉冲T为10 keV，持续了102 s。在短伽玛暴中，在暴末出现热成分是不寻常的。无论是硬成分还是软成分都不满足Amati关系，这使得GRB 170817 A与其他短暴有着明显的不同。基于γ射线和光学观测，我们建立了一个与GRB 170817 A相关的瞬发高能辐射模型。两颗中子星的合并产生了一个10−2 M的吸积环，它为黑洞提供了磁通量，并限制了布兰德福德-兹纳杰克动力喷流。我们将硬的快速尖峰与来自盘风的喷流的准球形爆发联系起来。当喷流以亚相对论速度穿过风时，它会产生一个以辐射为主的激波，将风的物质加热到数十千电子伏，产生软热成分。
We present our observations of electromagnetic transients associated with GW170817/GRB 170817A using optical telescopes of Chilescope observatory and Big Scanning Antenna (BSA) of Pushchino Radio Astronomy Observatory at 110 MHz. The Chilescope observatory detected an optical transient of ∼19m on the third day in the outskirts of the galaxy NGC 4993; we continued observations following its rapid decrease. We put an upper limit of 1.5 × 104 Jy on any radio source with a duration of 10–60 s, which may be associated with GW170817/GRB 170817A. The prompt gamma-ray emission consists of two distinctive components—a hard short pulse delayed by ∼2 s with respect to the LIGO signal and softer thermal pulse with T ∼ 10 keV lasting for another ∼2 s. The appearance of a thermal component at the end of the burst is unusual for short GRBs. Both the hard and the soft components do not satisfy the Amati relation, making GRB 170817A distinctively different from other short GRBs. Based on gamma-ray and optical observations, we develop a model for the prompt high-energy emission associated with GRB 170817A. The merger of two neutron stars creates an accretion torus of ∼10−2 M⊙, which supplies the black hole with magnetic flux and confines the Blandford–Znajek-powered jet. We associate the hard prompt spike with the quasispherical breakout of the jet from the disk wind. As the jet plows through the wind with subrelativistic velocity, it creates a radiation-dominated shock that heats the wind material to tens of kiloelectron volts, producing the soft thermal component.