Title: ALFABURST: A commensal search for Fast Radio Bursts with Arecibo,
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.