Reverse Shocks in the Relativistic Outflows of Gravitational Wave Detected Neutron Star Binary Mergers. (arXiv:1903.03320v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Lamb_G/0/1/0/all/0/1">Gavin P Lamb</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kobayashi_S/0/1/0/all/0/1">Shiho Kobayashi</a>
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 reverse shock will be observable as a brightening feature in the
rising afterglow at radio frequencies for bursts at $<100$,Mpc and systems
inclined $lesssim30^circ$ (or $sim 5$ times the core opening angle) at
$sim1-10$,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/polarimetry of the reverse shock could reveal the presence of a
strong magnetic field associated with the merger remnant.
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 reverse shock will be observable as a brightening feature in the
rising afterglow at radio frequencies for bursts at $<100$,Mpc and systems
inclined $lesssim30^circ$ (or $sim 5$ times the core opening angle) at
$sim1-10$,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/polarimetry of the reverse shock could reveal the presence of a
strong magnetic field associated with the merger remnant.
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