Search for directional associations between Baikal Gigaton Volume Detector neutrino-induced cascades and high-energy astrophysical sources

TL;DR

This study analyzes high-energy neutrino cascade data from Baikal-GVD to identify potential associations with astrophysical sources, focusing on high-energy events and their correlation with blazars and Galactic sources, despite limited statistical significance.

Contribution

It introduces a refined analysis of Baikal-GVD cascade data, emphasizing directional associations with astrophysical sources using improved angular resolution and Monte Carlo simulations.

Findings

No statistically significant associations found.

Possible links between neutrino triplet and Galactic sources.

Potential correlations with bright, flaring blazars.

Abstract

Baikal-GVD has recently published its first measurement of the diffuse astrophysical neutrino flux, performed using high-energy cascade-like events. We further explore the Baikal-GVD cascade dataset collected in 2018-2022, with the aim to identify possible associations between the Baikal-GVD neutrinos and known astrophysical sources. We leverage the relatively high angular resolution of the Baikal-GVD neutrino telescope (2-3 deg.), made possible by the use of liquid water as the detection medium, enabling the study of astrophysical point sources even with cascade events. We estimate the telescope's sensitivity in the cascade channel for high-energy astrophysical sources and refine our analysis prescriptions using Monte-Carlo simulations. We primarily focus on cascades with energies exceeding 100 TeV, which we employ to search for correlation with radio-bright blazars. Although the currently limited neutrino sample size provides no statistically significant effects, our analysis suggests a number of possible associations with both extragalactic and Galactic sources. Specifically, we present an analysis of an observed triplet of neutrino candidate events in the Galactic plane, focusing on its potential connection with certain Galactic sources, and discuss the coincidence of cascades with several bright and flaring blazars.