A determination of the composition of primary cosmic rays in the energy range between 1 and 1000 PeV is an important objective in studies of processes involving the formation and propagation of ...cosmic rays. On the basis of experience gained in exploiting the SPHERE-2 balloon-based facility, a SPHERE-3 facility, which possesses a wider aperture and a better optical resolution, is developed. The current status of work on designing this facility is presented.
High-energy cosmic-ray research via the detection of Cherenkov radiation from extensive air showers was begun in the Tunka valley (50 km to the west from the southern extremity of Lake Baikal) in the ...early 1990s. A series of large arrays combined into the TAIGA (Tunka Advanced Instrument for cosmic-ray physics and Gamma Astronomy) astrophysical facility and designed to study gamma rays and charged cosmic rays have been created in the elapsed time. Descriptions of the facility arrays and the main results obtained while investigating high-energy cosmic rays are presented. Plans for a further development of the astrophysical facility are discussed.
This paper presents the results of an analysis of observations of the Crab Nebula gamma-ray source with the first two atmospheric Cherenkov telescopes of the TAIGA (Tunka Advanced Instrument for ...cosmic ray physics and Gamma Astronomy) astrophysical complex in the stereo mode of observations. The article analyzed observational data from 2020 to 2021. Over 36 hours of observations, a signal was obtained at a statistical significance level of 5
and a spectrum of gamma rays was plotted in the energy range from 2 to 70 TeV. The paper describes a technique for gamma–hadron separation and reconstruction of detected gamma-rays energy.
A wide-angle Cerenkov array TAIGA-HiSCORE (FOV
0.6 sr), was originally created as a part of TAIGA installation for high-energy gamma-ray astronomy and cosmic ray physics. Array now consist on nearly ...100 optical stations on the area of 1 km
. Due to high accuracy and stability (
1 ns) of time synchronization of the optical stations the accuracy of EAS arrival direction reconstruction is reached 0.1
. It was proven that the array can also be used to search for nanosecond events of the optical range. The report discusses the method of searching for optical transients using the HiSCORE array and demonstrates its performance on a real example of detecting signals from an artificial Earth satellite. The search for this short flares in the HiSCORE data of the winter season 2018–2019 is carried out. One candidate for double repeater has been detected, but the estimated probability of random simulation of such a transient by background EAS events is not less than 10
, which does not allow us to say that the detected candidate corresponds to a real astrophysical transient. An upper bound on the frequency of optical spikes with flux density of more than
and a duration of more than 5 ns is established as
events/sr/h.
TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy) Astrophysical complex is being developed for studies of gamma rays and charged cosmic rays in the energy range of 10
–10
...eV. The complex is located in the Tunka Valley, about 50 km from Lake Baikal. In this report we present the experiment status and plans for study of high-energy cosmic-ray physics as well as main results reached by wide-angle TAIGA-HiSCORE and Tunka-133 Cherenkov arrays of the Astrophysical complex. Plans to study cosmic rays by means of other arrays of the complex, namely scintillation array Tunka-Grande and new TAIGA-muons array and system of IACT telescopes, are discussed too.
Paper contains the first results on the development of a SPHERE-3 telescope for the primary cosmic ray studies in 1–1000 PeV energy range using reflected and direct Cherenkov light generated by ...extensive air showers. It also sheds some light on the development of our new approach to the design of the new telescope.
Further development of the way of studying primary cosmic rays by detecting the reflected extensive air shower Cherenkov light is planned, based on the successful implementation of the SPHERE-2 ...aerostat experiment. The possibility of simultaneously detecting direct and reflected Cherenkov light from extensive air showers is demonstrated. Prospects for creating a new SPHERE-3 detector are discussed and the first results from modeling are presented.
The study of cosmic rays mass composition is an important problem in high-energy physics. The main goal of the SPHERE-2 experiment was to study the energy spectrum of the primary cosmic rays in the ...10–300 PeV energy range. Also the experimental data allow approaching their mass composition. The separation of events into nuclei groups makes it possible to estimate the average masses over the sample. Using machine learning methods, we developed a separation method for the primary nuclei groups that formed extensive air showers based on the simulated events for the SPHERE-2 telescope. Various models of the high energy nucleus-nucleus interaction were used, but their predictions differ significantly. In the SPHERE-2 experiment data analysis, this problem was solved, first, by the use of the data on Cherenkov light, which has weak dependence on the model of hadronic interaction; second, the neural network was trained simultaneously on two interaction models (QGSJET-01 and QGSJETII-04), which differ greatly from each other. Therefore, the independence of experimental data processing from the choice of the nuclear interaction model was ensured. The regression task is solved by machine learning methods. The separation of events into three groups of nuclei—protons (p), nitrogen (N), and iron (Fe)—by using a neural network is more precise than that by using traditional methods.
The more correct recalculation from the measured Cherenkov light fluxes at distances of 200 (Q200) and 100 (Q100) m from the Extensive Air Shower (EAS) core to the energy of the primary particle has ...been developed using the results of M-C simulation by the CORSIKA code, assuming a light primary composition of cosmic rays. Using the new conversion expressions, a differential energy spectrum was obtained according to the data of the Tunka-133 array for 7 years of operation and the TAIGA-HiSCORE array for 2 years of operation.
An analysis is performed of the spectrum of gamma rays from the Crab Nebula in the 4–100 TeV range of energies, obtained using data from two Atmospheric Cherenkov Telescopes that are part of the ...TAIGA complex. A way of selecting and restoring the energy of gamma rays is described that includes a procedure for restoring the energy spectrum.
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