14th of September 2022 |
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ATNF Colloquium |
Scattering Horizons for Fast Radio Bursts |
Stella Ocker (Cornell) |
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.
The image above shows all-sky maps of the dispersion measure (left) and scattering time (right) contributions of galaxies within 100 Mpc (Ocker et al. 2022, Astrophysical Journal, 934, 71O). |