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Reverse Shocks in the Relativistic Outflows of Gravitational Wave Detected Neutron Star Binary Mergers
journal contributionposted on 2019-09-09, 16:04 authored by Gavin P. Lamb, Shiho Kobayashi
The afterglows to gamma-ray bursts (GRBs) are due to synchrotron emission from shocks generated as an ultra-relativistic outflow decelerates. A forward and a reverse shock will form, however, where emission from the forward shock is well studied as a potential counterpart to gravitational wave-detected neutron star mergers the reverse shock has been neglected. Here, we show how the reverse shock contributes to the afterglow from an off-axis and structured outflow. The off-axis reverse shock will appear as a brightening feature in the rising afterglow at radio frequencies. For bursts at ∼ 100 Mpc, the system should be inclined . 20◦ for the reverse shock to be observable at ∼ 0.1 − 10 days post-merger. For structured outflows, enhancement of the reverse shock emission by a strong magnetic field within the outflow is required for the emission to dominate the afterglow at early times. Early radio photometry of the afterglow could reveal the presence of a strong magnetic field associated with the central engine.
GPL is supported by STFC grant ST/S000453/1.
CitationMonthly Notices of the Royal Astronomical Society, 489, 1820–1827 (2019)
Author affiliation/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy
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