A unified picture of Galactic and cosmological fast radio bursts. (arXiv:2005.06736v4 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Lu_W/0/1/0/all/0/1">Wenbin Lu</a> (Caltech), <a href="http://arxiv.org/find/astro-ph/1/au:+Kumar_P/0/1/0/all/0/1">Pawan Kumar</a> (UT Austin), <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_B/0/1/0/all/0/1">Bing Zhang</a> (UNLV)
The discovery of a fast radio burst (FRB) in our galaxy associated with a
magnetar (neutron star with strong magnetic field) has provided a critical
piece of information to help us finally understand these enigmatic transients.
We show that the volumetric rate of Galactic-FRB like events is consistent with
the faint end of the cosmological FRB rate, and hence they most likely belong
to the same class of transients. The Galactic FRB had an accompanying X-ray
burst but many X-ray bursts from the same object had no radio counterpart.
Their relative rates suggest that for every FRB there are roughly 10^2 to 10^3
X-ray bursts. The radio lightcurve of the galactic FRB had two spikes separated
by 30 ms in the 400-800 MHz frequency band. This is an important clue and
highly constraining of the class of models where the radio emission is produced
outside the light-cylinder of the magnetar. We suggest that magnetic
disturbances close to the magnetar surface propagate to a distance of a few
tens of neutron star radii where they damp and produce radio emission. The
coincident hard X-ray spikes associated with the two FRB pulses seen in this
burst and the flux ratio between the two frequency bands can be understood in
this scenario. This model provides a unified picture for faint bursts like the
Galactic FRB as well as the bright events seen at cosmological distances.
The discovery of a fast radio burst (FRB) in our galaxy associated with a
magnetar (neutron star with strong magnetic field) has provided a critical
piece of information to help us finally understand these enigmatic transients.
We show that the volumetric rate of Galactic-FRB like events is consistent with
the faint end of the cosmological FRB rate, and hence they most likely belong
to the same class of transients. The Galactic FRB had an accompanying X-ray
burst but many X-ray bursts from the same object had no radio counterpart.
Their relative rates suggest that for every FRB there are roughly 10^2 to 10^3
X-ray bursts. The radio lightcurve of the galactic FRB had two spikes separated
by 30 ms in the 400-800 MHz frequency band. This is an important clue and
highly constraining of the class of models where the radio emission is produced
outside the light-cylinder of the magnetar. We suggest that magnetic
disturbances close to the magnetar surface propagate to a distance of a few
tens of neutron star radii where they damp and produce radio emission. The
coincident hard X-ray spikes associated with the two FRB pulses seen in this
burst and the flux ratio between the two frequency bands can be understood in
this scenario. This model provides a unified picture for faint bursts like the
Galactic FRB as well as the bright events seen at cosmological distances.
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