Updates to the Fermi GBM Targeted Sub-threshold Search in Preparation for the Third Observing Run of LIGO/Virgo

TL;DR

This paper describes enhancements to the Fermi GBM targeted sub-threshold search for gravitational-wave counterparts, improving sensitivity and speed for LIGO/Virgo O3 observations through automation and updated localization methods.

Contribution

The paper introduces specific improvements to the Fermi GBM search algorithm, including automation and updated localization, enhancing detection capabilities for LIGO/Virgo O3.

Findings

Increased sensitivity compared to O2 search.

Faster processing enabling real-time analysis.

Successful implementation of automated upperlimits estimation.

Abstract

In this document, we detail the improvements made to the Fermi GBM targeted sub-threshold search for counterparts to LIGO/Virgo gravitational-wave triggers. We describe the implemented changes and compare the sensitivity of the O3 search to that of the version of the search that operated during O2. Overall, we have improved both the sensitivity and speed of the targeted search. Further improvements to the search have been made for the O3b observing run, including automated upperlimits estimation and incorporating the updated localization systematic with the new version of the search.