Searching for electromagnetic counterpart of LIGO gravitational waves in the Fermi GBM data with ADWO

TL;DR

This paper introduces ADWO, an unsupervised algorithm for detecting weak electromagnetic signals in Fermi GBM data, successfully identifying known and potential counterparts to gravitational wave events.

Contribution

The paper presents ADWO, a novel unsupervised, multi-channel detection method that independently analyzes Fermi GBM data to find electromagnetic counterparts of gravitational waves.

Findings

Successfully identified GRB150522B in Fermi data.

Detected possible electromagnetic counterparts to GW150914 and LVT151012.

Demonstrated ADWO's effectiveness in weak signal detection.

Abstract

The Fermi collaboration identified a possible electromagnetic counterpart of the gravitational wave event of September 14, 2015. Our goal is to provide an unsupervised data analysis algorithm to identify similar events in Fermi's Gamma-ray Burst Monitor CTTE data stream. We are looking for signals that are typically weak. Therefore, they can only be found by a careful analysis of count rates of all detectors and energy channels simultaneously. Our Automatized Detector Weight Optimization (ADWO) method consists of a search for the signal, and a test of its significance. We developed ADWO, a virtual detector analysis tool for multi-channel multi-detector signals, and performed successful searches for short transients in the data-streams. We have identified GRB150522B, as well as possible electromagnetic candidates of the transients GW150914 and LVT151012. ADWO is an independently developed, unsupervised data analysis tool that only relies on the raw data of the Fermi satellite. It can therefore provide a strong, independent test to any electromagnetic signal accompanying future gravitational wave observations.