2,022 research outputs found
Expected high energy emission from GRB 080319B and origins of the GeV emission of GRBs 080514B, 080916C and 081024B
We calculate the high energy (sub-GeV to TeV) prompt and afterglow emission
of GRB 080319B that was distinguished by a naked-eye optical flash and by an
unusual strong early X-ray afterglow. There are three possible sources for high
energy emission: the prompt optical and -ray photons IC scattered by
the accelerated electrons, the prompt photons IC scattered by the early
external reverse-forward shock electrons, and the higher band of the
synchrotron and the synchrotron self-Compton emission of the external shock.
There should have been in total {hundreds} high energy photons detectable for
the Large Area Telescope (LAT) onboard the Fermi satellite, and {tens} photons
of those with energy GeV. The GeV emission had a duration about
twice that of the soft -rays. AGILE could have observed these energetic
signals if it was not occulted by the Earth at that moment. The physical
origins of the high energy emission detected in GRB 080514B, GRB 080916C and
GRB 081024B are also discussed. These observations seem to be consistent with
the current high energy emission models.Comment: Accepted for publication in MNRAS, the interpretation of GRB 080916C
has been extended, main conclusions are unchange
GRB/GW association: Long-short GRB candidates, time-lag, measuring gravitational wave velocity and testing Einstein's equivalence principle
Short-duration gamma-ray bursts (SGRBs) are widely believed to be powered by
the mergers of compact binaries, such as binary neutron stars or possibly
neutron star-black hole binaries. Though the prospect of detecting SGRBs with
gravitational wave (GW) signals by the advanced Laser Interferometer
Gravitational-Wave Observatory (LIGO)/VIRGO network is promising, no known SGRB
has been found within the expected advanced LIGO/VIRGO sensitivity range for
binary neutron star systems. We find, however, that the two long-short GRBs
(GRB 060505 and GRB 060614) may be within the horizon of advanced GW detectors.
In the upcoming era of GW astronomy, the merger origin of some long-short GRBs,
as favored by the macronova signature displayed in GRB 060614, can be
unambiguously tested. The model-dependent time lags between the merger and the
onset of the prompt emission of the GRB are estimated. The comparison of such
time lags between model predictions and the real data expected in the era of
the GW astronomy would be helpful in revealing the physical processes taking
place at the central engine (including the launch of the relativistic outflow,
the emergence of the outflow from the dense material ejected during the merger,
and the radiation of gamma rays). We also show that the speed of GWs, with or
without a simultaneous test of Einstein's equivalence principle, can be
directly measured to an accuracy of or
even better in the advanced LIGO/VIRGO era. The Astrophysical Journal, VolumeComment: 12 pages, 3 figures, published in The Astrophysical Journa
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