ALFABURST: A commensal search for Fast Radio Bursts with Arecibo

TL;DR

ALFABURST conducted a commensal search for Fast Radio Bursts using Arecibo from 2015 to 2017, resulting in no FRB detections but identifying a Galactic transient and pulsar signals, providing constraints on FRB rates.

Contribution

This work presents the first long-term commensal FRB search with Arecibo, including system description, non-detection results, and a new Galactic transient discovery.

Findings

No FRBs detected in 518 hours of observation.

Estimated survey volume probed redshifts up to 3.4.

Detected a Galactic radio transient and pulsar signals.

Abstract

ALFABURST has been searching for Fast Radio Bursts (FRBs) commensally with other projects using the Arecibo L-band Feed Array (ALFA) receiver at the Arecibo Observatory since July 2015. We describe the observing system and report on the non-detection of any FRBs from that time until August 2017 for a total observing time of 518 hours. With current FRB rate models, along with measurements of telescope sensitivity and beam size, we estimate that this survey probed redshifts out to about 3.4 with an effective survey volume of around 600,000 Mpc$^3$. Based on this, we would expect, at the 99% confidence level, to see at most two FRBs. We discuss the implications of this non-detection in the context of results from other telescopes and the limitation of our search pipeline. During the survey, single pulses from 17 known pulsars were detected. We also report the discovery of a Galactic radio transient with a pulse width of 3 ms and dispersion measure of 281 pc cm$^{-3}$, which was detected while the telescope was slewing between fields.