A Population of Fast Radio Bursts at Cosmological Distances

Abstract

Searches for transient astrophysical sources often reveal unexpected classes of objects that are useful physical laboratories. In a recent survey for pulsars and fast transients, we have uncovered four millisecond-duration radio transients all more than 40° from the Galactic plane. The bursts' properties indicate that they are of celestial rather than terrestrial origin. Host galaxy and intergalactic medium models suggest that they have cosmological redshifts of 0.5 to 1 and distances of up to 3 gigaparsecs. No temporally coincident x- or gamma-ray signature was identified in association with the bursts. Characterization of the source population and identification of host galaxies offers an opportunity to determine the baryonic content of the universe.

A New Electron-Density Model for Estimation of Pulsar and FRB Distances

“…Lorimer et al (2007) assumed a DM Host of 200 cm −3 pc in their analysis of the original FRB010724, but DM contributions from elliptical galaxies or randomly oriented spirals are likely to be less than that, especially given the time dilation factor. Following Thornton et al (2013) and Caleb et al (2016), we adopt = DM 100…”

“…For example, it can help to identify pulsars that are likely to be in other galaxies, such as the Magellanic Clouds, by their excess DM over that expected from the Galaxy (e.g., Manchester et al 2006), and to firmly establish that "fast radio bursts" (FRBs) are distant extragalactic sources (e.g., Thornton et al 2013). A knowledge of the n e distribution along the path is important for the interpretation of Faraday rotation in pulsars and extragalactic sources when investigating the large-scale structure of the Galactic magnetic field (e.g., Han et al 2006;Van Eck et al 2011) and for the interpretation of measurements of interstellar scattering (e.g., Bower et al 2014;Lewandowski et al 2015).…”

Fast Radio Bursts as Probes of Magnetic Fields in the Intergalactic Medium

“…These large DMs imply that FRBs occur at cosmological redshifts, z∼0.5-1 (Thornton et al 2013;Dolag et al 2015). have reported the first detection of linear polarization in a FRB: for FRB110523, find DM=623.3 pc cm −3 and RM=−186 rad m −2 , and conclude that the RM was induced in the vicinity of the source itself or within the host galaxy.…”

“…Dispersion measure (DM), the free electron column density along the LOS, has been suggested as a possible probe of the IGM density (Ioka 2003;Inoue 2004), but can only be measured for the IGM by observation of a bright, brief, radio transient at cosmological distances. Fast radio bursts (FRBs) are a new phenomenon which appear to indeed provide us with these measurements of extragalactic DMs (Lorimer et al 2007(Lorimer et al , 2013; Keane et al 2012Keane et al , 2016Kashiyama et al 2013; Thornton et al 2013;Totani 2013;Zhang 2014;Champion et al 2015;Macquart et al 2015;Masui & Sigurdson 2015;Petroff et al 2015;Spitler et al 2016).…”

Why ultra-powerful radio bursts are the most perplexing mystery in astronomy

“…Bailes and his team kept going, and upgraded the Parkes detector's time and frequency resolution. In 2013, they turned up four new FRB candidates that resembled the Lorimer burst 4 . But some outsiders remained sceptical that the signals were really coming from space -not least because all the FRBs thus far had been seen by one team using one telescope.…”