Baikal-GVD is a neutrino telescope currently under construction in Lake Baikal. GVD is formed by multi-meganton subarrays (clusters). The design of Baikal-GVD allows one to search for astrophysical ...neutrinos already at early phases of the array construction. We present here preliminary results of a search for high-energy neutrinos with GVD in 2019-2020.
Baikal-GVD is a kilometer scale neutrino telescope currently under construction in Lake Baikal. Due to water currents in Lake Baikal, individual photomultiplier housings are mobile and can drift away ...from their initial position. In order to accurately determine the coordinates of the photomultipliers, the telescope is equipped with an acoustic positioning system. The system consists of a network of acoustic modems, installed along the telescope strings and uses acoustic trilateration to determine the coordinates of individual modems. This contribution discusses the current state of the positioning in Baikal-GVD, including the recent upgrade to the acoustic modem polling algorithm.
The Baikal-GVD is a neutrino telescope under construction in Lake Baikal. The main goal of the Baikal-GVD is to observe neutrinos via detecting the Cherenkov radiation of the secondary charged ...particles originating in the interactions of neutrinos. In 2021, the installation works concluded with 2304 optical modules installed in the lake resulting in effective volume approximately 0.4 km\(^{3}\). In this paper, the first steps in the development of double cascade reconstruction techniques are presented.
The Baikal-GVD (Gigaton Volume Detector) is a km\(^{3}\)- scale neutrino telescope located in Lake Baikal. Currently (year 2021) the Baikal-GVD is composed of 2304 optical modules divided to 8 ...independent detection units, called clusters. Specific neutrino interactions can cause Cherenkov light topology, referred to as a cascade. However, cascade-like events originate from discrete stochastic energy losses along muon tracks. These cascades produce the most abundant background in searching for high-energy neutrino cascade events. Several methods have been developed, optimized, and tested to suppress background cascades.
The Baikal-GVD deep underwater neutrino experiment participates in the international multi-messenger program on discovering the astrophysical sources of high energy fluxes of cosmic particles, while ...being at the stage of deployment with a gradual increase of its effective volume to the scale of a cubic kilometer. In April 2021 the effective volume of the detector has been reached 0.4 km3 for cascade events with energy above 100 TeV generated by neutrino interactions in Lake Baikal. The alarm system in real-time monitoring of the celestial sphere was launched at the beginning of 2021, that allows to form the alerts of two ranks like "muon neutrino" and "VHE cascade". Recent results of fast follow-up searches for coincidences of Baikal-GVD high energy cascades with ANTARES/TAToO high energy neutrino alerts and IceCube GCN messages will be presented, as well as preliminary results of searches for high energy neutrinos in coincidence with the magnetar SGR 1935+2154 activity in period of radio and gamma burst in 2020.
The first stage of the construction of the deep underwater neutrino telescope Baikal-GVD is planned to be completed in 2024. The second stage of the detector deployment is planned to be carried out ...using a data acquisition system based on fibre optic technologies, which will allow for increased data throughput and more flexible trigger conditions. A dedicated test facility has been built and deployed at the Baikal-GVD site to test the new technological solutions. We present the principles of operation and results of tests of the new data acquisition system.
We present data on the Baikal water luminescence collected with the Baikal-GVD neutrino telescope. This three-dimensional array of photo-sensors allows the observation of time and spatial variations ...of the ambient light field. We report on annual increase of luminescence activity in years 2018-2020. We observed a unique event of a highly luminescent layer propagating upwards with a maximum speed of 28 m/day for the first time.
Baikal-GVD is a gigaton-scale neutrino observatory under construction in Lake Baikal. It currently produces about 100 GB of data every day. For their automatic processing, the Baikal Analysis and ...Reconstruction software (BARS) was developed. At the moment, it includes such stages as hit extraction from PMT waveforms, assembling events from raw data, assigning timestamps to events, determining the position of the optical modules using an acoustic positioning system, data quality monitoring, muon track and cascade reconstruction, as well as the alert signal generation. These stages are implemented as C++ programs which are executed sequentially one after another and can be represented as a directed acyclic graph. The most resource-consuming programs run in parallel to speed up processing. A separate Python package based on the luigi package is responsible for program execution control. Additional information such as the program execution status and run metadata are saved into a central database and then displayed on the dashboard. Results can be obtained several hours after the run completion.
The Cherenkov Telescope Array and the KM3NeT neutrino telescopes are major upcoming facilities in the fields of \(\gamma\)-ray and neutrino astronomy, respectively. Possible simultaneous production ...of \(\gamma\) rays and neutrinos in astrophysical accelerators of cosmic-ray nuclei motivates a combination of their data. We assess the potential of a combined analysis of CTA and KM3NeT data to determine the contribution of hadronic emission processes in known Galactic \(\gamma\)-ray emitters, comparing this result to the cases of two separate analyses. In doing so, we demonstrate the capability of Gammapy, an open-source software package for the analysis of \(\gamma\)-ray data, to also process data from neutrino telescopes. For a selection of prototypical \(\gamma\)-ray sources within our Galaxy, we obtain models for primary proton and electron spectra in the hadronic and leptonic emission scenario, respectively, by fitting published \(\gamma\)-ray spectra. Using these models and instrument response functions for both detectors, we employ the Gammapy package to generate pseudo data sets, where we assume 200 hours of CTA observations and 10 years of KM3NeT detector operation. We then apply a three-dimensional binned likelihood analysis to these data sets, separately for each instrument and jointly for both. We find that the largest benefit of the combined analysis lies in the possibility of a consistent modelling of the \(\gamma\)-ray and neutrino emission. Assuming a purely leptonic scenario as input, we obtain, for the most favourable source, an average expected 68% credible interval that constrains the contribution of hadronic processes to the observed \(\gamma\)-ray emission to below 15%.
The KM3NeT/ARCA neutrino detector is currently under construction at 3500 m depth offshore Capo Passero, Sicily, in the Mediterranean Sea. The main science objectives are the detection of high-energy ...cosmic neutrinos and the discovery of their sources. Simulations were conducted for the full KM3NeT/ARCA detector, instrumenting a volume of 1 km\(^3\), to estimate the sensitivity and discovery potential to point-like neutrino sources and an all-sky diffuse neutrino flux. This paper covers the reconstruction of track- and shower-like signatures, as well as the criteria employed for neutrino event selection. By leveraging both the track and shower observation channels, the KM3NeT/ARCA detector demonstrates the capability to detect the diffuse astrophysical neutrino flux within half a year of operation, achieving a 5\(\sigma\) statistical significance. With an angular resolution below 0.1\(^\circ\) for tracks and under 2\(^\circ\) for showers, the sensitivity to point-like neutrino sources surpasses existing observed limits across the entire sky.
