Fast Radio Bursts---A Brief Review: Some Questions, Fewer Answers

TL;DR

This review discusses the nature, possible origins, and key properties of Fast Radio Bursts, highlighting their mysterious origins, high brightness temperatures, and potential links to known astrophysical phenomena.

Contribution

It provides a concise overview of the current understanding and open questions regarding FRB origins, emphasizing the need for further observational and theoretical studies.

Findings

FRBs are millisecond radio bursts at ~1 GHz with high dispersion.

They are likely at cosmological distances with redshifts 0.3-1.3.

Their brightness temperatures suggest coherent emission mechanisms.

Abstract

Fast Radio Bursts are millisecond bursts of radio radiation at frequencies of about 1 GHz, recently discovered in pulsar surveys. They have not yet been definitively identified with any other astronomical object or phenomenon. The bursts are strongly dispersed, indicating passage through a high column density of low density plasma. The most economical interpretation is that this is the interglactic medium, indicating that FRB are at "cosmological" distances with redshifts in the range 0.3--1.3. Their inferred brightness temperatures are as high as $10^{37\,\circ}$K, implying coherent emission by "bunched" charges, as in radio pulsars. I review the astronomical sites, objects and emission processes that have been proposed as the origin of FRB, with particular attention to Soft Gamma Repeaters and giant pulsar pulses.