Fast radio burst detection in the presence of coloured noise

In this paper, we investigate the impact of correlated noise on fast radio burst (FRB) searching. We found that (1) the correlated noise significantly increases the false alarm probability; (2) the signal-to-noise ratios (S/N) of the false positives become higher; (3) the correlated noise also affects the pulse width distribution of false positives, and there will be more false positives with wider pulse width. We use 55-h observation for M82 galaxy carried out at Nanshan 26m radio telescope to demonstrate the application of the correlated noise modelling. The number of candidates and parameter distribution of the false positives can be reproduced with the modelling of correlated noise. We will also discuss a low S/N candidate detected in the observation, for which we demonstrate the method to evaluate the false alarm probability in the presence of correlated noise. Possible origins of the candidate are discussed, where two possible pictures, an M82-harboured giant pulse and a cosmological FRB, are both compatible with the observation.

Automated summary

This study investigates the impact of correlated noise on the search for fast radio bursts (FRBs), finding that it significantly increases false alarm probability, raises signal-to-noise ratios of false positives, and affects the pulse width distribution. Demonstrating the application of correlated noise modeling with observations of the M82 galaxy, the study also discusses a low signal-to-noise candidate and its possible origins. Both an M82-harbored giant pulse and a cosmological FRB are compatible with the observed data.