Astropulse: A Search for Microsecond Transient Radio Signals Using Distributed Computing. I. Methodology

TL;DR

Astropulse is a sky survey using the Arecibo telescope to detect microsecond-scale radio pulses, employing distributed computing for coherent dedispersion to explore transient signals.

Contribution

This paper introduces a novel methodology for microsecond transient radio signal detection using distributed computing for coherent dedispersion.

Findings

Successfully collected 1,540 hours of data per beam

Detected transient signals on microsecond timescales

Demonstrated feasibility of distributed computing for real-time processing

Abstract

We are performing a transient, microsecond timescale radio sky survey, called "Astropulse," using the Arecibo telescope. Astropulse searches for brief (0.4 {\mu}s to 204.8 {\mu}s), wideband (relative to its 2.5 MHz bandwidth) radio pulses centered at 1,420 MHz. Astropulse is a commensal (piggyback) survey, and scans the sky between declinations of -1.33 and 38.03 degrees. We obtained 1,540 hours of data in each of 7 beams of the ALFA receiver, with 2 polarizations per beam. Examination of timescales on the order of a few microseconds is possible because we used coherent dedispersion. The more usual technique, incoherent dedispersion, cannot resolve signals below a minimum timescale. However, coherent dedispersion requires more intensive computation than incoherent dedispersion. The required processing power was provided by BOINC, the Berkeley Open Infrastructure for Network Computing.