PulsarX: a new pulsar searching package -I. A high performance folding program for pulsar surveys

TL;DR

PulsarX introduces a high-performance pulsar searching pipeline that optimizes candidate folding using novel algorithms, significantly reducing computational costs and enhancing real-time survey capabilities with applications to MeerKAT data.

Contribution

The paper presents the pruned FDMT algorithm and a Tikhonov-regularised folding method, improving efficiency and resolution in pulsar candidate processing for large-scale surveys.

Findings

Reduced dedispersion operations by a factor of 50 for 500 candidates

Implemented successful real-world application with MeerKAT surveys

Enhanced time resolution of pulsar profiles using TLSM

Abstract

Pulsar surveys with modern radio telescopes are becoming increasingly computationally demanding. This is particularly true for wide field-of-view pulsar surveys with radio interferometers, and those conducted in real or quasi-real time. These demands result in data analysis bottlenecks that can limit the parameter space covered by the surveys and diminish their scientific return. In this paper, we address the computational challenge of `candidate folding' in pulsar searching, presenting a novel, efficient approach designed to optimise the simultaneous folding of large numbers of pulsar candidates. We provide a complete folding pipeline appropriate for large-scale pulsar surveys including radio frequency interference (RFI) mitigation, dedispersion, folding and parameter optimization. By leveraging the Fast Discrete Dispersion Measure Transform (FDMT) algorithm proposed by Zackay et al. (2017), we have developed an optimized, and cache-friendly implementation that we term the pruned FDMT (pFDMT). The pFDMT approach efficiently reuses intermediate processing results and prunes the unused computation paths, resulting in a significant reduction in arithmetic operations. In addition, we propose a novel folding algorithm based on the Tikhonov-regularised least squares method (TLSM) that can improve the time resolution of the pulsar profile. We present the performance of its real-world application as an integral part of two major pulsar search projects conducted with the MeerKAT telescope: the MPIfR-MeerKAT Galactic Plane Survey (MMGPS) and the Transients and Pulsars with MeerKAT (TRAPUM) project. In our processing, for approximately 500 candidates, the theoretical number of dedispersion operations can be reduced by a factor of around 50 when compared to brute-force dedispersion, which scales with the number of candidates.