Fast Radio Burst Breakouts from Magnetar Burst Fireballs

Abstract

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 $T\gtrsim 30$ keV entail an electron--positron ($e^{\pm }$) outflow from a trapped--expanding fireball, polluting the NS magnetosphere before the FRB emission. The $e^{\pm }$ outflow is opaque to FRB photons, and is strongly Compton-dragged by the X-ray bursts. Nevertheless, the FRB photons can break out of the $e^{\pm }$ 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 $e^{\pm }$ 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.

9 pages, 3 figures, accepted for publication in ApJ Letter

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Cited by in corpus (22)

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• Coherent inverse Compton scattering by bunches in fast radio bursts
• Magnetospheric curvature radiation by bunches as emission mechanism for repeating fast radio bursts
• Transparency of Fast Radio Burst Waves in Magnetar Magnetospheres
• Binary comb models for FRB 121102
• Statistical modelling of the cosmological dispersion measure
• Polarisation of magnetospheric curvature radiation in repeating fast radio bursts
• Limits on Fast Radio Burst-like Counterparts to Gamma-ray Bursts using CHIME/FRB
• Expanding Fireball in Magnetar Bursts and Fast Radio Bursts
• Multi-wavelength and Multi-messenger Counterparts of Fast Radio Bursts
• Evolution of magnetic deformation in neutron star crust
• On the energy budget of starquake-induced repeating fast radio bursts
• Hyper-active repeating fast radio bursts from rotation modulated starquakes on magnetars
• Fast Radio Bursts
• Periodic Activities of Fast Radio Burst Repeaters from Precessing Magnetars with Evolving Obliquity
• Eclipsed X-ray Bursts from Magnetar SGR J1935+2154 and the Fireball Measurements
• A Target Search for Fast Radio Bursts Associated with Two Fast Blue Optical Transients: AT2018cow and CSS161010
• Multi-Wavelength Constraints on the Outflow Properties of the Extremely Bright Millisecond Radio Bursts from the Galactic Magnetar SGR 1935+2154
• Spectral Evidence of Heavy Nuclei from the Neutron Star Crust in Magnetar Bursts
• Optical Transients from Fast Radio Bursts Heating Companion Stars in Close Binary Systems