A Fast Radio Burst Search Method for VLBI Observation

TL;DR

This paper presents a novel, efficient cross spectrum-based method for detecting fast radio bursts in VLBI data, improving sensitivity and RFI robustness without high computational costs.

Contribution

The paper introduces a new FRB search technique for VLBI that leverages cross spectrum fringe fitting, enhancing detection confidence and reducing computational complexity.

Findings

Increased detection confidence through multi-baseline cross-identification.

Reduced RFI effects compared to auto spectrum methods.

Suitable for VGOS observations due to its efficiency.

Abstract

We introduce the cross spectrum based FRB (Fast Radio Burst) search method for VLBI observation. This method optimizes the fringe fitting scheme in geodetic VLBI data post processing, which fully utilizes the cross spectrum fringe phase information and therefore maximizes the power of single pulse signals. Working with cross spectrum greatly reduces the effect of radio frequency interference (RFI) compared with using auto spectrum. Single pulse detection confidence increases by cross identifying detections from multiple baselines. By combining the power of multiple baselines, we may improve the detection sensitivity. Our method is similar to that of coherent beam forming, but without the computational expense to form a great number of beams to cover the whole field of view of our telescopes. The data processing pipeline designed for this method is easy to implement and parallelize, which can be deployed in various kinds of VLBI observations. In particular, we point out that VGOS observations are very suitable for FRB search.