How to search for multiple messengers -- a general framework beyond two messengers

TL;DR

This paper introduces a Bayesian framework for optimally searching for multi-messenger cosmic events involving any number of messengers, addressing the lack of a model-independent optimal search method.

Contribution

It presents a scalable, model-dependent Bayesian approach for multi-messenger searches, extending beyond two messengers and applicable to diverse models.

Findings

Developed a general Bayesian method for multi-messenger searches.

Demonstrated the method with a joint gravitational wave, neutrino, and gamma-ray burst example.

Showed that a model-independent optimal search does not exist.

Abstract

Quantification of the significance of a candidate multi-messenger detection of cosmic events is an emerging need in the astrophysics and astronomy communities. In this paper we show that a model-independent optimal search does not exist, and we present a general Bayesian method for the optimal model-dependent search, which is scalable to any number and any kind of messengers, and applicable to any model. In the end, we demonstrate it through an example for a joint gravitational wave, high-energy neutrino, short gamma-ray burst event search; which has not been examined heretofore.