Title: Disentangling the Cosmic Web with Fast Radio Bursts

Abstract: I will report on a set of new, well-localized (<1”) fast radio bursts (FRBs) discovered primarily by the ASKAP telescope.  Nearly each of these events is coincident with a luminous galaxy which we designate as the host. The properties of these host galaxies and the spatial distribution of the FRBs within them rule out several classes of models proposed for FRBs.  Spectra of the galaxies establish the FRB redshifts and offer a first assessment of the dispersion measure vs. redshift relation. This yields a new estimate of the cosmic baryon density for the low-z universe, consistent with measurements from BBN and the CMB, i.e. the so-called “missing” baryons have been detected!  Last (time permitting), we analyze the rotation measure and pulse width of one FRB to study the magnetic field and density of gas in a foreground galaxy halo.