A New Framework to Detect Multi-Messenger Signals from Bright Sporadic Stochastic Gravitational Wave Background

TL;DR

This paper introduces MC², a new analysis pipeline that enhances detection of multi-messenger signals from the stochastic gravitational-wave background by combining GW and electromagnetic data, reducing false alarms and enabling better understanding of high-redshift sources.

Contribution

The paper presents a novel multi-messenger cross-correlation framework for detecting EM counterparts to the SGWB, applicable to both modeled and unmodeled sources, improving detection confidence.

Findings

Demonstrated the effectiveness of MC² in reducing false alarm rates.

Showed the potential to discover EM counterparts to weak GW signals.

Outlined observation strategies for current and future missions.

Abstract

The temporal dependence of the astrophysical stochastic gravitational-wave (GW) background (SGWB) in the hecto-hertz band brings a unique avenue to identify multi-messenger signals to these sources by using coincident detection in both GW and multi-band EM signals. We developed a new analysis pipeline, \textit{Multi-messenger Cross-Correlation} (MC$^2$) that can search for EM counterparts to the SGWB signal originating from both modeled and unmodeled sources by harnessing the nearly full-sky gamma-ray sky map. We provide an observation strategy that can be followed by current and future missions to discover EM counterparts to the weak GW signal hidden in the SGWB. We demonstrate the ability of this technique to drastically reduce the false alarm rates when involving EM multi-band analysis. This formalism aims towards advancing the multi-messenger observation frontier and improving our understanding of the population of bright SGWB sources present in the high-redshift universe and can also be applied to other messengers such as neutrinos in the future.