# Unidentified FRBs in archival data

## TL;DR

This paper discusses the potential under-detection of Fast Radio Bursts (FRBs) in archival data, highlighting that many may remain undiscovered due to search limitations and the diverse nature of FRB signals.

## Contribution

It reveals how and why certain FRBs were missed in archival searches and emphasizes the need to improve search pipelines to detect more diverse FRB signals.

## Key findings

- Up to 40% of discoverable FRBs may be undetected in existing data.
- Current search pipelines are biased towards symmetric, broadband flat-spectrum pulses.
- Most FRBs do not conform to the typical search criteria, leading to missed detections.

## Abstract

Recently Zhang et al. (2019) reported the discovery of FRB 010312 in a dataset previously searched for FRBs. Here we explain how and why this FRB was initially missed, and highlight several caveats relevant to FRB search completeness. It is possible that up to $\sim40$% of discoverable FRBs remain undiscovered in some existing public domain archival data sets. The situation could be even more pronounced given that FRB search pipelines generally look for temporally-symmetric broadband flat-spectrum pulses; most FRBs do not look like that.