Localizing a Fast Radio Burst for the first time

Author:  Benito Marcote


Abstract: Fast Radio Bursts (FRBs) are radio transient sources that emit a single pulse with a duration of only a few milliseconds.  They were firstly discovered in 2007, and nowadays we have detected tens of these events using single-dish radio observatories. However, their physical origin remains completely unknown mainly due to the limited resolution of these instruments.

Here we present the first unambiguous localization of a Fast Radio Burst. FRB 121102, which is the only FRB to have shown repeated bursts, was observed simultaneously with the 305-m Arecibo Telescope and the Karl G. Jansky Very Large Array (VLA). The detection of the bursts using Arecibo allowed us to image them with the VLA data, localizing the bursts with less than one arcsec precision. An even more precise localization was afterwards made by combining Arecibo with the European VLBI Network (EVN). The bursts are coincident with a persistent and compact radio source with a projected size of less than 0.7 pc. This radio source is located in a dwarf low-metallicity galaxy at a redshift of 0.1927.

These results provide the first confirmation of the extragalactic origin of FRBs. Additionally, we argue that a burst source associated with a low-luminosity active galactic nucleus or a young neutron star energizing a supernova remnant are the two scenarios that best match the observed data of FRB 121102.