2020ApJ...904L..15I -
Astrophys. J., 904, L15-L15 (2020/December-1)
Fast radio burst breakouts from magnetar burst fireballs.
IOKA K.
Abstract (from CDS):
The recent discovery of a Mega-Jansky radio burst occurring simultaneously with short X-ray bursts from the Galactic magnetar (strongly magnetized neutron star (NS)) SGR 1935+2154 is a smoking gun for the hypothesis that some cosmological fast radio bursts (FRBs) arise from magnetar bursts. We argue that the X-ray bursts with high temperature T >= 30 keV entail an electron-positron (e±) outflow from a trapped-expanding fireball, polluting the NS magnetosphere before the FRB emission. The e± outflow is opaque to induced Compton scatterings of FRB photons, and is strongly Compton-dragged by the X-ray bursts. Nevertheless, the FRB photons can break out of the e± outflow with radiation forces if the FRB emission radius is larger than a few tens of NS radii. A FRB is choked if the FRB is weaker or the X-ray bursts are stronger, possibly explaining why there are no FRBs with giant flares and no detectable X-ray bursts with weak FRBs. We also speculate that the e± outflow may be inevitable for FRBs, solving the problem of why the FRBs occur only with high-T X-ray bursts. The breakout physics is important for constraining the emission mechanism and electromagnetic counterparts to future FRBs.
Abstract Copyright:
© 2020. The American Astronomical Society. All rights reserved.
Journal keyword(s):
Radio transient sources - Magnetars - Pulsars - X-ray bursts - Non-thermal radiation sources - Relativistic mechanics
Simbad objects:
3
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