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

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.Comment: 10 pages, 3 figure

Large neutrino telescope Baikal-GVD: recent status

The Baikal-GVD is a deep-underwater neutrino telescope being constructed in Lake Baikal. After the winter 2023 deployment campaign the detector consists of 3456 optical modules installed on 96 vertical strings. The status of the detector and progress in data analysis are discussed in present report. The Baikal-GVD data collected in 2018-2022 indicate the presence of cosmic neutrino flux in high-energy cascade events consistent with observations by the IceCube neutrino telescope. Analysis of track-like events results in identification of first high-energy muon neutrino candidates. These and other results from 2018-2022 data samples are reviewed in this report

ANTARES offline study of three alerts after Baikal-GVD follow-up found coincident cascade neutrino events

ANTARES and Baikal-GVD are both Cherenkov neutrino telescopes located in the Northern Hemisphere so their fields of view almost overlap allowing for a combined study of the sky. ANTARES sends alerts after a fast online analysis based on energy and reconstruction direction of track-like events. From December of 2018 until the beginning of 2021, Baikal-GVD received 38 ANTARES alerts, and followed up 32. No coincidence was found. However, a search of the Baikal-GVD cascade sample showed some events falling within an angular distance of less than 5° for three of the ANTARES alerts in a time span of 48 hours. A dedicated offline analysis based on the full ANTARES data sample has been started to search for additional coincident tracks and cascades at a 3σ significance. In this work we present the final results of the offline analysis of the three ANTARES alerts: limits on the astrophysical neutrino fluence are reported