The FRB-searching pipeline of the Tianlai Cylinder Pathfinder Array

TL;DR

This paper details the design and implementation of a real-time FRB search pipeline for the Tianlai Cylinder Pathfinder Array, achieving successful detection of known pulsars and the first FRB discovery with high recall.

Contribution

It introduces a novel real-time FRB search pipeline integrated with the Tianlai array, including calibration, survey strategy, and beam arrangement optimization.

Findings

Detected four known pulsars during commissioning.

Achieved an 88% recall rate in FRB candidate detection.

Reported the first FRB discovery by the Tianlai array.

Abstract

This paper presents the design, calibration, and survey strategy of the Fast Radio Burst (FRB) digital backend and its real-time data processing pipeline employed in the Tianlai Cylinder Pathfinder array. The array, consisting of three parallel cylindrical reflectors and equipped with 96 dual-polarization feeds, is a radio interferometer array designed for conducting drift scans of the northern celestial semi-sphere. The FRB digital backend enables the formation of 96 digital beams, effectively covering an area of approximately 40 square degrees with 3 dB beam. Our pipeline demonstrates the capability to make automatic search of FRBs, detecting at quasi-real-time and classify FRB candidates automatically. The current FRB searching pipeline has an overall recall rate of 88\%. During the commissioning phase, we successfully detected signals emitted by four well-known pulsars: PSR B0329+54, B2021+51, B0823+26, and B2020+28. We report the first discovery of an FRB by our array, designated as FRB 20220414A. We also investigate the optimal arrangement for the digitally formed beams to achieve maximum detection rate by numerical simulation.