ausblenden:
Schlagwörter:
Astrophysics, High Energy Astrophysical Phenomena, astro-ph.HE,General Relativity and Quantum Cosmology, gr-qc
Zusammenfassung:
We explore the electromagnetic counterparts that will associate with binary
neutron star mergers for the case that remnant massive neutron stars survive
for $\gtrsim 0.5$ s after the merger. For this study, we employ the outflow
profiles obtained by long-term general-relativistic neutrino-radiation
magneto-hydrodynamics simulations with a mean field dynamo effect. We show that
a synchrotron afterglow with high luminosity can be associated with the merger
event if the magnetic fields of the remnant neutron stars are significantly
amplified by the dynamo effect. We also perform a radiative transfer
calculation for kilonovae and find that for the highly amplified magnetic field
cases, the kilonovae can be bright in the early epoch ($t\leq 0.5\,{\rm d}$),
while it shows rapid declining ($\lesssim 1\,{\rm d}$) emission and
long-lasting ($\sim 10\,{\rm d}$) emission in the optical and near-infrared
wavelength, respectively. All these features have not been found in GW170817,
indicating that the merger remnant neutron star formed in GW170817 might have
collapsed to a black hole within several hundreds ms or magnetic-field
amplification might be a minor effect.
