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The astrophysical complex TAIGA (Tunka Advanced Instrument for cosmic-ray physics and Gamma-ray Astronomy), whose first phase is being completed in the Tunka valley 50 km from Lake Baikal, is described. Its research program, first results, and development prospects are discussed.

The importance and advantages of the hybrid approach developed within the TAIGA project for studying the high-energy section of the spectrum of gamma radiation in the Universe are discussed. The pilot complex of the TAIGA gamma observatory with an area of 1 km $${}^{2}$$ is briefly described along with the lines of its development, and the first results obtained on this basis are given.

Work is currently under way in the Tunka Valley, 50 km from Lake Baikal, to create the TAIGA gamma observatory for studying gamma radiation and cosmic ray fluxes in the 1013–1018 eV range of energies. To detect gamma rays with energies above tens of TeV, a hybrid method of detecting showers is implemented. It is based on data obtained by the TAIGA Imaging Atmospheric Cherenkov Telescope (IACT) and the wide-angle TAIGA-HiSCORE array. The preliminary results from processing the telescope’s data for the low-energy region (>2–3 TeV) are presented. Joint events with energy more than 50 TeV are analyzed and compared to Monte Carlo calculations.

The TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma-ray Astronomy) experiment aims at observing gamma-rays in the energy range from 1 TeV to several 100 TeV. The operation of the observatory is based on a new hybrid approach that combines imaging air Cherenkov telescopes (IACTs) and wide-angle Cherenkov detectors (TAIGA-HiSCORE) for measuring times of extensive air shower (EAS) light front arrival. Monte Carlo simulations are compared to real data to determine the performance of the detector setup. Dedicated software and algorithms are described, model parameters are given, and an overview of the current status of model-based performance studies is presented.

The relevance and benefits of the new TAIGA gamma observatory complex in the Tunka Valley (50 km from Lake Baikal) are discussed. The main aim of the TAIGA installation is to study high-energy gamma radiation and search for cosmic pevatrons. The first series of gamma stations was commissioned in 2019 and covers an area of 1 km2. Its expected integral gamma radiation sensitivity at an energy of 100 TeV over 300 h of source monitoring is (2–5) × 10−13 TeV cm−2 s−1. It is planned to expand the effective area of TAIGA gamma observation to 10 km2 in the future.

The Tunka-133 Cherenkov complex for recording extensive air showers (EAS) collected data over seven winters from 2009 to 2017. The differential energy spectra of all particles was acquired in the 6 × 1015–3 × 1018 eV range of energies over 2175 h. The TAIGA-HiSCORE complex is continually being expanded and upgraded. Data acquired by 30 first-line stations over 35 days during the period 2017–2018 is analyzed in this work. As at the Tunka-133 setup, the primary particle energies above 1015 eV are measured using the density of the Cherenkov light flux at a distance of 200 m from a shower’s axis. Data on lower energies are collected by determining the energy of the light flux near a shower’s axis. This results in a spectrum of 2 × 1014–1017 eV. The combined spectrum for the two systems covers a range of 2 × 1014–2 × 1018 eV.

37th International Cosmic Ray Conference, ICRC 2021, Berlin, online, Germany, 12 Jul 2021 - 23 Jul 2021; Proceedings of Science / International School for Advanced Studies (ICRC2021), 938 (2021). doi:10.22323/1.395.0938, Challenges faced by researchers in multi-messenger astroparticle physics include: computing-intensive search and preprocessing related to the diversity of content and formats of the data from different observatories as well as to data fragmentation over separate storage locations; inconsistencies in user interfaces for data retrieval; lack of the united infrastructure solutions suitable for both data gathering and online analysis, e.g. analyses employing deep neural networks. In order to address solving these issues, the German-Russian Astroparticle Data Life Cycle Initiative (GRADLCI) was created. In addition, we support activities for communicating our research field to the public. The approaches proposed by the project are based on the concept of data life cycle, which assumes a particular pipeline of data curation used for every unit of the data from the moment of its retrieval or creation through the stages of data preprocessing, analysis, publishing and archival. The movement towards unified data curation schemes is essential to increase the benefits gained in the analysis of geographically distributed or content-diverse data. Within the project, an infrastructure for effective astroparticle data curation and online analysis was developed. Using it, first results on deep-learning based analysis were obtained., Published by SISSA, Trieste

Multi-messenger astroparticle physics is still a young field of research and is hardly covered in educational curricula or outreach. The astroparticle.online project, founded in 2018 within the framework of the German-Russian Astroparticle Data Life Cycle Initiative (GRADLCI), encompasses an endeavor to address this issue. Within the project, scientists from Karlsruhe Institute of Technology (KIT), Irkutsk State University (ISU) and Moscow State University (MSU) developed a range of educational materials: articles, video lectures, tests, problems to solve, laboratory works and pre-trained neural networks for particle recognition. The project is supported by the KASCADE Cosmic-ray Data Center (KCDC) and GRADLCI data aggregation platform, where one can retrieve and analyze open scientific data from various experiments. The main audience of the project's activities are high school and undergraduate students. All the educational materials are available online at the project's web portal astroparticle.online, they are used both in online and offline masterclasses organized by the project members, and also as the supplementary content by educational organizations: for example, in the ISU course "Introduction to experimental methods in high energy astrophysics". Over the time the project has been operating, more than 150 students took part in its activities. This contribution will cover the experience gained while running the project for more than 3 years, our challenges and developments.

The article presents the relevance and advantages of the new gamma observatory TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy), which is being constructed in the Tunka Valley 50 km from Lake Baikal. Various detectors of the six TAIGA gamma observatory arrays register the Cherenkov and radio radiation, as well as the electron and muon components of EAS. The primary objective of the TAIGA gamma observatory is to study the high-energy part of the gamma-ray spectrum, in particular, in order to search for Galactic PeVatrons. The energy, direction, and position of the EAS axis are reconstructed in the observatory based on the data of the wide-angle Cherenkov detectors of the TAIGA-HiSCORE experiment. Taking into account this information, the gamma quanta are distinguished from the hadron background using the data obtained by the muon detectors and telescopes that register the EAS image in the Cherenkov light. In this hybrid mode of operation, the atmospheric Cherenkov telescopes can operate in the mono-mode, and the distance between them can be increased to 800–1000 m, which makes it possible to construct an array with an area of 5 km2 and more at relatively low cost and in a short time. By 2019, the first stage of the gamma observatory with an area of 1 km2 will be constructed; its expected integral sensitivity for detecting the gamma radiation with an energy of 100 TeV at observation of the source for 300 hours will be approximately $$2 \times 5$$ 10–13 TeV cm–2s–1.

36th International Cosmic Ray Conference, ICRC2019, Madison, USA, 24 Jul 2019 - 1 Aug 2019; PoS(ICRC2019)284 (2019)., A data life cycle (DLC) is a high-level data processing pipeline that involves data acquisition, event reconstruction, data analysis, publication, archiving, and sharing. For astroparticle physics a DLC is particularly important due to the geographical and content diversity of the research field. A dedicated and experiment spanning analysis and data centre would ensure that multi-messenger analyses can be carried out using state-of-the-art methods. The German-Russian Astroparticle Data Life Cycle Initiative (GRADLCI) is a joint project of the KASCADE-Grande and TAIGA collaborations, aimed at developing a concept and creating a DLC prototype that takes into account the data processing features specific for the research field. An open science system based on the KASCADE Cosmic Ray Data Centre (KCDC), which is a web-based platform to provide the astroparticle physics data for the general public, must also include effective methods for distributed data storage algorithms and techniques to allow the community to perform simulations and analyses with sophisticated machine learning methods. The aim is to achieve more efficient analyses of the data collected in different, globally dispersed observatories, as well as a modern education to Big Data Scientist in the synergy between basic research and the information society. The contribution covers the status and future plans of the initiative.

The Tunka-Grande scintillation array is described. The first results from its operation are presented. The prospects for studying primary cosmic rays in the energy range of 1016 to 1018 eV during simultaneous registration of the Cherenkov and charged particle components along with radio emissions from extensive air showers are discussed.

The combination of a wide angle timing Cherenkov array and Imaging Atmospheric Cherenkov Telescopes operated in mono mode offers a cost-effective way to construct a few square kilometers array for ultrahigh-energy gamma astronomy. The first stage of the TAIGA Observatory (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy) is described here. It will comprise TAIGA-HiSCORE - 120 wide angle Cherenkov stations distributed over an area of 1.0 km2 and three IACTs (TAIGA-IACT).

Data 3(4), 56 (2018). doi:10.3390/data3040056, Modern large-scale astroparticle setups measure high-energy particles, gamma rays, neutrinos, radio waves, and the recently discovered gravitational waves. Ongoing and future experiments are located worldwide. The data acquired have different formats, storage concepts, and publication policies. Such differences are a crucial point in the era of Big Data and of multi-messenger analysis in astroparticle physics. We propose an open science web platform called ASTROPARTICLE.ONLINE which enables us to publish, store, search, select, and analyze astroparticle data. In the first stage of the project, the following components of a full data life cycle concept are under development: describing, storing, and reusing astroparticle data; software to perform multi-messenger analysis using deep learning; and outreach for students, post-graduate students, and others who are interested in astroparticle physics. Here we describe the concepts of the web platform and the first obtained results, including the meta data structure for astroparticle data, data analysis by using convolution neural networks, description of the binary data, and the outreach platform for those interested in astroparticle physics. The KASCADE-Grande and TAIGA cosmic-ray experiments were chosen as pilot examples., Published by MDPI, Basel

Modern experimental astroparticle physics features large-scale setups measuring different messengers, namely high-energy particles generated by cosmic accelerators (e.g. supernova remnants, active galactic nuclei, etc): cosmic and gamma rays, neutrinos and recently discovered gravitational waves. Ongoing and future experiments are distributed over the Earth including ground, underground/underwater setups as well as balloon payloads and spacecrafts. The data acquired by these experiments have different formats, storage concepts and publication policies. Such differences are a crucial issue in the era of big data and of multi-messenger analysis strategies in astroparticle physics. We propose a service ASTROPARTICLE.ONLINE in the frame of which we develop an open science system which enables to publish, store, search, select and analyse astroparticle physics data. The cosmic-ray experiments KASCADE-Grande and TAIGA were chosen as pilot experiments to be included in this framework. In the first step of our initiative we will develop and test the following components of the full data life cycle concept: (i) describing, storing and reusing of astroparticle data; (ii) software for performing multi-experiment and multi-messenger analyses like deep-learning methods; (iii) outreach including example applications and tutorial for students and scientists outside the specific research field. In the present paper we describe the concepts of our initiative, and in particular the plans toward a common, federated astroparticle data storage.

In this work we compare two open source machine learning libraries, PyTorch and TensorFlow, as software platforms for rejecting hadron background events detected by imaging air Cherenkov telescopes (IACTs). Monte Carlo simulation for the TAIGA-IACT telescope is used to estimate background rejection quality. A wide variety of neural network algorithms provided by both libraries can easily be tested on various types of data, which is useful for various imaging air Cherenkov experiments. The work is a component of the Astroparticle.online project, which collaborates with the TAIGA and KASCADE experiments and welcomes any astroparticle experiment to join., 6 pages, 2 figures. Submitted to JPCS, 26th Extended European Cosmic Ray Symposium and 35th Russian Cosmic Ray Conference (E+CRS 2018 / RCRC 2018), Barnaul - Belokurikha, July 6 - 10, 2018

The TAIGA observatory addresses ground-based gamma-ray astronomy at energies from a few TeV to several PeV, as well as cosmic ray physics from 100 TeV to several EeV . TAIGA will be located in the Tunka valley, ~ 50 km West from Lake Baikal. The different detectors of the TAIGA will be grouped in 6 arrays to measure Cherenkov and radio emission as well as electron and muon components of atmospheric showers. The combination of the wide angle Cherenkov detectors of the TAIGA-HiSCORE array and the 4-m Imaging Atmospheric Cherenkov Telescopes of the TAIGA-IACT array with their FoV of 10×10 degrees and underground muon detectors offers a very cost effective way to construct a 5 km2 array for gamma-ray astronomy.

36th International Cosmic Ray Conference, Madison, USA, 24 Jul 2019 - 1 Aug 2019; PoS-ICRC2019-320 (2019)., Digital radio arrays are widely used for the low-frequency radio astronomy as well as for detection of air-showers induced by high-energy cosmic rays and neutrinos. Since the radio emission from air-showers forms short broadband pulses with duration of tens nanoseconds, the data acquisition strategies of cosmic-ray and astronomical arrays have significant differences. To perform precise measurement of cosmic rays, the radio array should have absolute amplitude calibration and record the entire electric field on the antenna in the broad frequency range. These requirements are similar to ones defined for the experiments aimed at the detection of weak signal from neutral hydrogen at redshifts of $z$>10, what led us to the application of our experience with Tunka-Rex to this problem. We are developing new experimental setup comprising of four antenna stations, placed on the area of 100 sq.m. Each antenna station consists of two perpendicular loop antennas measuring electric field in the frequency band of 30-80 MHz. The setup records electric fields from all antennas in portions of 50 $\mu$s reaching the spectral resolution of 20 kHz. We expect a flow of redundant data of about 10 GB/day, and plan to exploit this redundancy in order to decrease systematic uncertainty of the measurements by application of digital beam-forming, matched filtering and RFI suppression with neural networks. In the present contribution we describe the design and calibration of the setup, expected performance and data analysis techniques.