Fast radio bursts: the observational case for a Galactic origin

TL;DR

This paper presents observational evidence supporting the hypothesis that fast radio bursts originate from nearby flare stars, challenging the cosmological origin theory and suggesting a local stellar source based on optical and radio data analysis.

Contribution

It provides new optical observations of potential flare star counterparts in FRB fields and re-evaluates the likelihood of a Galactic origin for FRBs, including the case of repeating bursts.

Findings

Possible flare star associations in multiple FRB fields.

High probability that two FRBs are from the same repeating source.

Dispersion measures are inconsistent with a cosmological origin.

Abstract

There are by now ten published detections of fast radio bursts (FRBs), single bright GHz-band millisecond pulses of unknown origin. Proposed explanations cover a broad range from exotic processes at cosmological distances to atmospheric and terrestrial sources. Loeb et al. have previously suggested that FRB sources could be nearby flare stars, and pointed out the presence of a W-UMa-type contact binary within the beam of one out of three FRB fields that they examined. Using time-domain optical photometry and spectroscopy, we now find possible flare stars in additional FRB fields, with one to three such cases among eight FRB fields studied. We evaluate the chance probabilities of these possible associations to be in the range 0.1% to 9%, depending on the input assumptions. Further, we re-analyze the probability that two FRBs recently discovered 3 years apart within the same radio beam are unrelated. Contrary to other claims, we conclude with 99% confidence that the two events are from the same repeating source. The different dispersion measures between the two bursts then rule out a cosmological origin for the dispersion measure, but are consistent with the flare-star scenario with a varying plasma blanket between bursts. Finally, we review some theoretical objections that have been raised against a local flare-star FRB origin, and show that they are incorrect.