CHIME/Slow overview and pilot survey: A new backend to search for second-duration radio transients with the CHIME telescope

TL;DR

This paper introduces CHIME/Slow, a new backend for detecting second-duration radio transients with the CHIME telescope, presenting initial survey results, burst properties, and transient rate estimates.

Contribution

It presents the development and pilot testing of the CHIME/Slow pipeline for real-time second-duration radio transient detection, including initial survey results and transient rate estimation.

Findings

Detected nine radio bursts in 17 days of on-sky data.

Identified one new non-repeating and eight repeating bursts.

Estimated all-sky transient rate between 184 and 4556 bursts per day.

Abstract

We present an overview of CHIME/Slow, a real-time transient search backend under development to search for second-duration radio transients using the CHIME telescope, and results obtained from a pilot survey carried out using the prototype version of the search pipeline. The prototype CHIME/Slow pipeline was tested on archival data obtained in December 2022, January 2023 and February 2023 with a total on-sky time of 17 days with an instantaneous Field of View (FoV) of $\sim$13 deg$^2$ . In this pilot survey, we detected nine bursts, one from a new non-repeating source and eight from the known hyperactive repeating source FRB 20220912A. Out of these nine bursts, two bursts from the repeater were not detected by CHIME/FRB, while the non-repeater was detected in the side-lobe of a beam in the CHIME/FRB exhibiting shorter pulse width and narrower bandwidth compared to the CHIME/Slow detection. Here we report properties of the bursts, discuss the sensitivity and completeness of the current version of the CHIME/Slow pipeline, and outline future development to improve its performance. Finally, based on these results, we report the all-sky rate (95% credible region) of radio transients with pulse widths between 16 ms to 5 s, fluence above 5 Jy ms and observing frequency of 600 MHz to be between 184 and 4556 bursts sky$^{-1}$ day$^{-1}$.