Stella Ocker (Cornell University)

Stella Ocker colloquium: Scattering Horizons for Fast Radio Bursts

Abstract

Fast radio bursts (FRBs) flicker across the sky at millisecond timescales thousands of times per day. Despite their unknown origins, the chromatic propagation effects FRBs experience along their journeys to the observer can be used to probe the distribution and turbulence of ionized gas from the Milky Way to their host galaxies. FRB scattering, in particular, is sensitive to small-scale electron density fluctuations that are inaccessible to many other observational probes. In this talk, I will discuss current constraints on scattering in the circumgalactic medium and FRB host galaxies, and the implied prospects for probing these respective media with a large future sample of FRBs. In addition, I will discuss modelling of the cumulative scattering from the Milky Way to host galaxies for FRBs at redshifts > 1, which suggests that scattering may undermine the use of FRBs as probes of galaxies and cosmology from near the peak of cosmic star formation to the epoch of reionization.