Abstract
ABSTRACT Keane et al. have recently claimed to have obtained the first precise localization for a fast radio burst (FRB) thanks to the identification of a contemporaneous fading slow (∼week-timescale) radio transient. They use this localization to pinpoint the FRB to a galaxy at z ≈ 0.49 that exhibits no discernible star formation activity. We argue that the transient is not genuine and that the host candidate, WISE J071634.59−190039.2, is instead a radio variable: the available data did not exclude this possibility; a random radio variable consistent with the observations is not unlikely to have a redshift compatible with the FRB dispersion measure; and the proposed transient light curve is better explained as a scintillating steady source, perhaps also showing an active galactic nucleus (AGN) flare, than a synchrotron-emitting blastwave. The radio luminosity of the host candidate implies that it is an AGN and we present new late-time Very Large Array observations showing that the galaxy is indeed variable at a level consistent with the claimed transient. Therefore the claimed precise localization and redshift determination for FRB 150418 cannot be justified.
Highlights
The origin of Fast Radio Bursts (FRBs; Lorimer et al 2007) remains unknown, with both Galactic and extragalactic scenarios proposed (e.g., Falcke & Rezzolla 2013; Loeb et al 2014; Zhang 2014)
We show that the agreement between the host candidate redshift and the dispersion measure (DM) of FRB 150418 is not unlikely, if the host candidate was selected based on short-timescale radio variability
We performed a Markov Chain Monte Carlo (MCMC) simulation to characterize the host galaxy redshifts that would have been found to be consistent with the DM of FRB 150418, given the assumptions made by Keane et al (2016
Summary
The origin of Fast Radio Bursts (FRBs; Lorimer et al 2007) remains unknown, with both Galactic and extragalactic scenarios proposed (e.g., Falcke & Rezzolla 2013; Loeb et al 2014; Zhang 2014). The SUrvey for Pulsars and Extragalactic Radio Bursts (SUPERB) project has recently claimed to have obtained the first precise localization for an FRB by identification of an associated radio transient that faded over the course of six days (Keane et al 2016). This transient was located in a seemingly passive elliptical galaxy at z = 0.492 ± 0.008, a phenomenology which they argued to be consistent with the possible origin of (at least some) FRBs in compact object mergers (e.g., Zhang 2014). We provide several a priori reasons to doubt the association between FRB 150418 and WISE 0716−19
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
