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GRB 170817A as a jet counterpart to gravitational wave triggerGW 170817
journal contributionposted on 2019-07-03, 11:13 authored by Gavin P. Lamb, Shiho Kobayashi
Fermi/GBM (Gamma-ray Burst Monitor) and INTEGRAL (the International Gamma-ray Astrophysics Laboratory) reported the detection of the γ-ray counterpart, GRB 170817A, to the LIGO (Light Interferometer Gravitational-wave Observatory)/Virgo gravitational wave detected binary neutron star merger, GW 170817. GRB 170817A is likely to have an internal jet or another origin such as cocoon emission, shock-breakout, or a flare from a viscous disc. In this paper we assume that the γ-ray emission is caused by energy dissipation within a relativistic jet and we model the afterglow synchrotron emission from a reverse and forward shock in the outflow. We show the afterglow for a low-luminosity γ-ray burst (GRB) jet with a high Lorentz factor (Γ); a low-Γ and low-kinetic-energy jet; a low-Γ, high-kinetic-energy jet; structured jets viewed at an inclination within the jet-half-opening angle; and an off-axis ‘typical’ GRB jet. All jet models will produce observable afterglows on various time-scales. The late-time afterglow from 10 to 110 d can be fitted by a Gaussian structured jet viewed at a moderate inclination, however the GRB is not directly reproduced by this model. These jet afterglow models can be used for future gravitational wave detected neutron star merger counterparts with a jet afterglow origin.
This research was supported by Science Technology and Facilities Council grants. GPL was partially supported by International Astronomical Union and Royal Astronomical Society grants.
CitationMonthly Notices of the Royal Astronomical Society, 2018, 478 (1), pp. 733-740
Author affiliation/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy
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