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The physics motivations and advantages of the new TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy) detector are presented. TAIGA aims at gamma-ray astronomy at energies from a few TeV to several PeV, as well as cosmic ray physics from 100 TeV to several EeV. For the energy range 30 – 200 TeV the sensitivity of 10 km2 area TAIGA array for the detection of local sources is expected to be 5 × 10-14 erg cm-2 sec-1 for 300 h of observations. Reconstruction of the given EAS energy, incoming direction and its core position, based on the timing TAIGA-HiSCORE data, allows one to increase a distance between the IACTs up to 600-1000 m. The low investments together with the high sensitivity for energies ≥ 30-50 TeV make this pioneering technique very attractive for exploring the galactic PeVatrons and cosmic rays. At present the TAIGA first stage has been constructed in Tunka valley, 50 km West from the Lake Baikal. The first experimental results of the TAIGA first stage are presented.

This work presents the data on new finds of fossil macrotheriofauna in the reference sections of the Upper Neopleistocene sediments in the Tunka rift valley (southwestern Baikal Region). The osteological material of a number of Late Neopleistocene mammals including extinct species rare for the Baikal region such as Crocuta spelaea, Panthera spelaea, and Spirocerus kiakhtensis (?) was directly dated with a radiocarbon (AMS) method. The obtained 14C data (18000–35000 years) allow one to rejuvenate significantly the upper limit of the common age interval of habitat of these animals in southern part of Eastern Siberia. Cave hyena and spiral-horned antelope lived in the Tunka rift valley in the Baikal region in Late Kargino time (37–24 ka), and cave lion survived the maximum in the Sartan cryochron in the region (21–20 ka). The study of collected paleontological collections provides a basis for selection of independent Kargino (MIS 3) faunal assemblages to use them for regional biostratigraphic analysis of Pleistocene deposits. Radiocarbon age dating of samples allows one to attribute confidently all paleofaunal remains available to the second half of the Late Pleistocene.

This paper presents an overview of study of the Upper Pleistocene key sections of the southwestern Baikal area (Tunka rift valley, Baikal rift zone) and Prebaikalia (south of Siberian platform). Geochemical data have revealed some paleoclimatic variations in the region during the Late Pleistocene. The highest values of the lithochemical moduli are present in Kazantsevo deposits of the Ust-Odinsky section. They indicate a high degree of chemical transformation of rocks and accumulation of alumina and iron, which is characteristic of warm humid climate. The upper part of all studied sections, including the Holocene horizon (MIS 1), shows a significant decrease of all moduli values, a result of climate deterioration from Kazantsevo time (MIS 5) through Sartanian time (MIS 2). Moreover, there are two peaks of modulus values, corresponding to the Karginsky (MIS 3) paleosols. The analyses of the mammal faunal composition of the studied regions have revealed that in the Tunka rift valley the dominant forms of both large and small mammals are Central Asian species, arid open landscape dwellers. In contrast, in the Pebaikalian fauna the inhabitants of tundra, tundra-steppe are predominant. The fauna of Ust-Odinsky section (Murukta time, MIS 4) contains the representatives of a disharmonious fauna ( Lagurus lagurus and Dicrostonyx sp.). The mammal assemblages of the Kazantsevo (MIS 5) suggest rather humid and warm paleoenvironmental conditions, in contrast to the Karginsky (MIS 3) interval which is characterized by drier, moderate cold climate with steppe biotopes.

In TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma-ray Astronomy) detector we are commissioning the first Imaging Atmospheric Cherenkov Telescope (IACT). The telescope drive system comprises a motor controller and two stepper motors for axis control. For the pointing calibration of the telescope a CCD-camera is installed on the reflector dish of the telescope. The position of the CCD-camera allows us capturing both the Cherenkov camera and the observed source. In this report we describe the telescope positioning and the drive system software as well as the control of the CCD-camera data acquisition, archiving and processing system.

We report the first ground-based observation of the CATS-LIDAR onboard the ISS by the TAIGA-HiSCORE gamma-ray facility, and the MASTER-Tunka Robotic telescope. HiSCORE detects unscattered laser light directly from the ISS, at up to km-scale distance from the laser beam spot on ground. The ISS-LIDAR turns out to be a unique calibration tool, in particular to verify the absolute astronomical pointing of HiSCORE. We detected the LIDAR for 11 ISS-passages; among these were observations of forward scattering of the laser beam in dense clouds, which might carry information complementary to the LIDAR technique. We expect other air Cherenkov installations like IACTs to benefit from this light source.

The very to ultra high energy gamma-ray regime up to several 100 TeV is the key to spectrally resolve the cutoff regime of the long-sought Pevatrons, the Galactic cosmic-ray PeV accelerators. One component of the TAIGA hybrid detector is the TAIGA-HiSCORE shower-front sampling timing array, which currently consists of 28 wide angle (0.6\,sr) air Cherenkov timing stations distributed on an area of 0.25 km$^{2}$, and which will be doubled in area by fall 2017. We report on the status and first results of the HiSCORE timing array after the first 2 operation seasons, including calibration studies on timing and pointing, cross calibration with data from the first TAIGA-IACT, observations with the timing array of a LIDAR operating on the ISS, a measurement of the Cosmic Ray spectrum, and a systematic search for high energy gamma-rays from Galactic sources such as the Crab.

The physics motivations and characteristics of the new gamma-experiment TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy) are presented. The TAIGA experiment 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. For the energy range $30 - 200$ TeV the sensitivity of the planned for future extension of TAIGA up to $5$ km$^2$ area for detection of the local sources is expected to be $10^{-13}$ erg cm$^{-2}$ sec$^{-1}$ for $500$ h of observation. The combination of the wide angle Cherenkov timing detectors of the TAIGA-HiSCORE array and the $4$ m class Imaging Atmospheric Cherenkov Telescopes of the TAIGA-IACT array with their FoV of $10x10$ degrees offers a cost effective-way to construct a $5$ km$^2$ array. Reconstruction of an EAS energy, direction and core position based on the TAIGA-HiSCORE data will allow us to increase the distance between comparatively expensive IACTs up to $800 - 1200$ m. The low investments together with the high sensitivity for energies $\geqslant 30-50$ TeV make this pioneering technique very attractive for exploring the galactic PeVatrons and cosmic rays. In addition to the Cherenkov light detectors we intend to deploy an array of muon detectors (TAIGA-Muon array) over an area of 1 km$^2$ with a total area of about $2000 - 3000$ m$^2$. The TAIGA-IACT-HiSCORE together with the TAIGA-Muon array will be used for selection of gamma-ray induced EAS. At present the first stage of TAIGA have been constructed in the Tunka valley, $\sim 50$ km West from the Lake Baikal in Siberia. Now it consists of 28 TAIGA-HiSCORE Cherenkov stations distributed over an area of $0.25$ km$^2$ and the first IACT of the TAIGA-IACT array. We are planning to test operation of the single telescope in coincidence with the HiSCORE up to shower impact distances of $\sim 500 - 600$ m; for this purpose we already started construction of the second imaging telescope at $300$ m distance from the first one. During 2017 -- 2019 years we intend to increase the number of the TAIGA-HiSCORE stations up to $100 - 120$, spread on the area of $1$ km$^2$ and to deploy $2$ additional IACTs.

Nuclear instruments & methods in physics research / A 845, 367 - 372 (2017). doi:10.1016/j.nima.2016.08.031, The new TAIGA-HiSCORE non-imaging Cherenkov array aims to detect air showers induced by gamma rays above 30 TeV and to study cosmic rays above 100 TeV. TAIGA-HiSCORE is made of integrating air Cherenkov detector stations with a wide field of view (0.6 sr), placed at a distance of about 100 m. They cover an area of initially ∼0.25 km$^2$ (prototype array), and of ∼5 km$^2$ at the final phase of the experiment. Each station includes 4 PMTs with 20 or 25 cm diameter, equipped with light guides shaped as Winstone cones. We describe the design, specifications of the read-out, DAQ and control and monitoring systems of the array. The present 28 detector stations of the TAIGA-HiSCORE engineering setup are in operation since September 2015., Published by North-Holland Publ. Co., Amsterdam

Observations of gamma rays up to several 100 TeV are particularly important to spectrally resolve the cutoff regime of the long-sought Pevatrons, the cosmic-ray PeV accelerators. One component of the TAIGA hybrid detector is the TAIGA-HiSCORE timing array, which currently consists of 28 wide angle (0.6 sr) air Cherenkov timing stations distributed on an area of 0.25 km2 . The HiSCORE concept is based on (non-imaging) air shower front sampling with Cherenkov light. First results are presented.

Tunka-HiSCORE (HiSCORE: Hundred Square-km Cosmic Origin Explorer) is a new Cherenkov EAS arrayfor multi-TeV γ ray astronomy and cosmic ray studies. The array will consist of wide-angle (0.6 sr)optical stations with 150 m distance between individual stations. The array will be constructed in severalstages: beginning with a 1 km 2 array at the first stage up to 100 km at the last stage. The first threestations have been installed during 2012 in Tunka Valley (50 km from the Southern tip of Lake Baikal) atthe site of the Tunka-133 array. We describe the construction of the optical stations and the array DAQ,and present the first results of common operation of the new optical stations with the Tunka-133 array.& 2013 Elsevier B.V. All rights reserved. 1. IntroductionWe propose to explore the so far poorly measured cosmic ray andγ ray sky in the energy region from 20 TeV to 100 PeV with thelarge area wide-angle cosmic ray and γ ray detector Tunka-HiSCORE[1,2]. Tunka-HiSCORE will be a non-imaging Cherenkov light-frontsampling array with large sensitive area (0.5 m

TAIGA stands for "Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy" and is a project to build a complex, hybrid detector system for ground-based gamma- ray astronomy from a few TeV to several PeV, and for cosmic-ray studies from 100 TeV to 1 EeV. TAIGA will search for "PeVatrons" (ultra-high energy gamma-ray sources) and measure the composition and spectrum of cosmic rays in the knee region (100 TeV - 10 PeV) with good energy resolution and high statistics. TAIGA will include Tunka-HiSCORE (an array of wide-angle air Cherenkov stations), an array of Imaging Atmospheric Cherenkov Telescopes, an array of particle detectors, both on the surface and underground, and the TUNKA-133 air Cherenkov array.

The gamma-ray energy regime beyond 10 TeV is crucial for the search for the most energetic Galactic accelerators. The energy spectra of most known gamma-ray emitters only reach up to few 10s of TeV, with 80 TeV from the Crab Nebula being the highest energy so far observed significantly. Uncovering their spectral shape up to few 100 TeV could answer the question whether some of these objects are cosmic ray Pevatrons, i.e. Galactic PeV accelerators.Sensitive observations in this energy range and beyond require very large effective detector areas of several 10s to 100 square-km. While imaging air Cherenkov telescopes have proven to be the instruments of choice in the GeV to TeV energy range, very large area telescope arrays are limited by the number of required readout channels per instrumented square-km (due to the large number of channels per telescope). Alternatively, the shower-front sampling technique allows to instrument large effective areas and also naturally provides large viewing angles of the instrument. Solely measuring the shower front light density and timing (hence timing- arrays), the primary particle properties are reconstructed on the basis of the measured lateral density function and the shower front arrival times. This presentation gives an overview of the technique, its goals, and future perspective.

Up to several 10s of TeV, Imaging Air Cherenkov Telescopes (IACTs) have proven to be the instruments of choice for GeV/TeV gamma-ray astronomy due to their good reconstrucion quality and gamma-hadron separation power. However, sensitive observations at and above 100 TeV require very large effective areas (10 km2 and more), which is difficult and expensive to achieve.The alternative to IACTs are shower front sampling arrays (non-imaging technique or timing-arrays) with a large area and a wide field of view. Such experiments provide good core position, energy and angular resolution, but only poor gamma-hadron separation. Combining both experimental approaches, using the strengths of both techniques, could optimize the sensitivity to the highest energies.The TAIGA project plans to combine the non-imaging HiSCORE [8] array with small (~10m2) imaging telescopes. This paper covers simulation results of this hybrid approach.

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.

The physical motivations and advantages of the new gamma-observatory TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy) is presented. The TAIGA array is a complex, hybrid detector for ground-based gamma-ray astronomy for energies from a few TeV to several PeV as well as for cosmic ray studies from 100 TeV to several EeV. The TAIGA will include the wide angle Cherenkov array TAIGA-HiSCORE with ~5 km$^{2}$ area, a net of 16 IACT telescopes (with FOV of about 10x10 degree), muon detectors with a total area of up to 2000-3000 m$^{2}$ and the radio array Tunka-Rex.

Measurements of optical properties in media enclosing Cherenkov neutrino telescopes are important not only at the moment of the selection of an adequate site, but also for the continuous characterization of the medium as a function of time. Over the two last decades, the Baikal collaboration has been measuring the optical properties of the deep water in Lake Baikal (Siberia) where, since April 1998, the neutrino telescope NT-200 is in operation. Measurements have been made with custom devices. The NEMO Collaboration, aiming at the construction of a km3 Cherenkov neutrino detector in the Mediterranean Sea, has developed an experimental setup for the measurement of oceanographic and optical properties of deep sea water. This setup is based on a commercial transmissometer. During a joint campaign of the two collaborations in March and April 2001, light absorption, scattering and attenuation in water have been measured. The results are compatible with previous ones reported by the Baikal Collaboration and show convincing agreement between the two experimental techniques., Comment: 16 pages, submitted to NIM-A

The first IACT as part of the gamma and cosmic-ray experiment TAIGA was installed in the Tunka Valley near Lake Baikal in fall 2016. In the following months different systems of the telescope were put into test operation. We started the commissioning phase of operating the telescope in time coincidence with the wide angle integrating air Cherenkov HiSCORE array, which for the time being comprises 28 working stations. We anticipate that the hybrid operation of the non-imaging and imaging telescopes will lead to a cost-efficient, highly sensitive detector operating in the energy range from 30-50 TeV till several PeV. Here we want to report on the first test results of operating the prototype hybrid array. We will focus on the analysis of count rates and image size spectra for all events detected by the IACT and the joint events detected also by the HiSCORE array, comparing these with expectations from MC simulations.

The TAIGA (Tunka Advanced Instrument for cosmic rays and Gamma-Astronomy) observatory is designed to study the gamma ray sources and galactic cosmic rays. It is located in the Tunka Valley 50 km from the lake Baikal (Siberia). The first part of TAIGA called the EAS Cherenkov array TAIGA-HiSCORE currently consists of 28 wide-angle (0.6 sr) stations, distributed over an area of 0.25 km^2. The Crab observation exposure was about 115 hours during the winter seasons of 2016-2017. The expected gamma quanta excess depends on the array energy threshold and a model of the Crab energy spectrum extrapolation to the higher energies. We present preliminary results of experimental data and MC simulations comparison as well as energy threshold and angular resolutions. The experimental data is in a good agreement with the simulations. An excess of events (about 25 events in the region 30-63 TeV) observed from the Crab direction is compatible with the expected one.

The first imaging atmospheric Cherenkov telescope as a part of the TAIGA (Tunka Advanced Instrument for cosmic rays and Gamma Astronomy) detector was put into commission in the Tunka valley in December 2016. The reflector of the telescope follows the Davis-Cotton design. It is composed of 34 glassmirror tiles, each of 60 cm diameter, and has a diameter of 4.3 m. The focal length is 4.75 m. The imaging camera includes 560 photomultiplier-based pixels, providing a FoV of ~10×10 degrees. The imaging camera is made by using a modular principle and includes trigger, data acquisition and processing systems based on MAROC3 chips. The slow control system monitors the count rate and the PMT anode currents as well as controls the high voltage. For monitoring performance of the camera a dedicated calibration system based on nanosecond pulsed LED light source was developed.