Searching for the radio remnants of short duration gamma-ray bursts. (arXiv:2008.03659v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Ricci_R/0/1/0/all/0/1">Roberto Ricci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Troja_E/0/1/0/all/0/1">Eleonora Troja</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bruni_G/0/1/0/all/0/1">Gabriele Bruni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsumoto_T/0/1/0/all/0/1">Tatsuya Matsumoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piro_L/0/1/0/all/0/1">Luigi Piro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+OConnor_B/0/1/0/all/0/1">Brendan O'Connor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piran_T/0/1/0/all/0/1">Tsvi Piran</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Navaieelavasani_N/0/1/0/all/0/1">Niloofar Navaieelavasani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Corsi_A/0/1/0/all/0/1">Alessandra Corsi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Giacomazzo_B/0/1/0/all/0/1">Bruno Giacomazzo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wieringa_M/0/1/0/all/0/1">Mark H. Wieringa</a>
Neutron star mergers produce a substantial amount of fast-moving ejecta,
expanding outwardly for years after the merger. The interaction of these ejecta
with the surrounding medium may produce a weak isotropic radio remnant,
detectable in relatively nearby events. We use late-time radio observations of
short duration gamma-ray bursts (sGRBs) to constrain this model. Two samples of
events were studied: four sGRBs that are possibly in the local (<200 Mpc)
universe were selected to constrain the remnant non-thermal emission from the
sub-relativistic ejecta, whereas 17 sGRBs at cosmological distances were used
to constrain the presence of a proto-magnetar central engine, possibly
re-energezing the merger ejecta. We consider the case of GRB~170817A/GW170817,
and find that in this case the early radio emission may be quenched by the jet
blast-wave. In all cases, for ejecta mass range of M_ej lesssim 10^{-2} (5 *
10^{-2}) M_sun, we can rule out very energetic merger ejecta E_ej gtrsim 5 *
10^{52}(10^{53}) erg, thus excluding the presence of a powerful magnetar as a
merger remnant.
Neutron star mergers produce a substantial amount of fast-moving ejecta,
expanding outwardly for years after the merger. The interaction of these ejecta
with the surrounding medium may produce a weak isotropic radio remnant,
detectable in relatively nearby events. We use late-time radio observations of
short duration gamma-ray bursts (sGRBs) to constrain this model. Two samples of
events were studied: four sGRBs that are possibly in the local (<200 Mpc)
universe were selected to constrain the remnant non-thermal emission from the
sub-relativistic ejecta, whereas 17 sGRBs at cosmological distances were used
to constrain the presence of a proto-magnetar central engine, possibly
re-energezing the merger ejecta. We consider the case of GRB~170817A/GW170817,
and find that in this case the early radio emission may be quenched by the jet
blast-wave. In all cases, for ejecta mass range of M_ej lesssim 10^{-2} (5 *
10^{-2}) M_sun, we can rule out very energetic merger ejecta E_ej gtrsim 5 *
10^{52}(10^{53}) erg, thus excluding the presence of a powerful magnetar as a
merger remnant.
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