Astronomy & Astrophysics Seminar: A New Mechanism for Fast Radio Bursts

Zoom: https://tau-ac-il.zoom.us/j/81850414917?pwd=hOoiUteqh6KKoO6pzUfM8jmYjZJWZP.1

Abstract:

Fast radio bursts (FRBs) are bright millisecond radio flashes that can be detected from distant galaxies, yet their emission mechanism remains uncertain. Magnetars, neutron stars with the strongest known magnetic fields, are leading candidate sources. I will present a new mechanism operating in magnetar explosions. Small magnetar quakes preceding an explosion can drive magnetospheric turbulence, which in turn generates compressive kHz waves. The explosion launches a powerful electromagnetic pulse that sweeps through these waves. Stimulated scattering inside the pulse converts them into GHz waves directed nearly radially outward. The resulting radio burst rides inside the pulse, which helps it escape the magnetosphere and reach a distant observer. Its spectrum and temporal structure are calculated from first principles. For powerful magnetar explosions, the model predicts FRB energies and peak luminosities comparable to those of cosmological bursts. It can produce both broad and narrow spectra and predicts strong linear polarization. When stimulated scattering is sufficiently strong, the burst contains an exceptionally bright microsecond component.

Seminar Organizer: Dr. Jonathan Stern