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Cosmic rays are a very valuable tool of multi-messenger astrophysics, as they provide a very different picture of the sky. During the past decades, a large number of active astrophysical objects in our Galaxy and beyond have been discovered through the detection of gamma-rays with Cherenkov telescopes. Cosmic rays, neutrinos have been successfully supplementing the astronomical view. Also, cosmic rays may offer to investigation of the elementary particle properties. Neutrino telescope detects the Cherenkov radiation generated in water or ice by the passage of relativistic charged particles produced by neutrino collisions with nucleons in the detector volume. Some alternative approaches have been proposed. One of them is using earth matter or mountains as a target volume for the conversion of neutrinos to leptons which then initiate extensive air showers (EAS) in the atmosphere, then showers can be detected by the Cherenkov telescope. Investigations with SHALON Cherenkov telescope have included observations of EAS from the sub-horizontal direction $��\Theta �=�97�°�$. Five EAS of ∼10 TeV energies were detected with SHALON from the sub-horizontal directions in the conditions with the zero expected number of showers. These events may be caused by the decay of a long-lived penetrating particle entering the atmosphere from the ground and decaying in front of the telescope. As a possible explanation, two scenarios with an unstable neutrino of mass $��m�\approx �0.5�$ GeV and $���c�\tau ��\approx �30�$ m is discussed. Remarkably, one of these models has been proposed to explain an excess of electron-like neutrino events at MiniBooNE.

The investigation of supernova remnants (SNRs) across the electromagnetic spectrum from radio up to very high energy gamma-rays can serve as a test of the particle acceleration and touches on one of the unresolved problems of modern astrophysics, namely the origin of cosmic rays and the Galaxy's contribution to the overall cosmic ray spectrum. The multiwavelength observations of Cas A SNR demonstrated that structure and spectral features have clear signs of young SNRs and its overall properties make this object the best target to test a hypothesis of cosmic ray origin in SNRs. Studies of Cas A at very high energies by SHALON telescope showed the location of TeV gamma-ray emission region relative to the position of reveres shock. Also, the spectral energy distribution was obtained at high and very high energies. To describe the spectral and structural features of this SNR viewed in non-thermal emission, two approaches involving reverse and also both reverse and forward shocks to the mechanism of diffusive shock acceleration of cosmic rays in Cas A were applied. It is demonstrated that the observational properties of Cas A are well reproduced by the hadronic model with significant contribution of both the forward and reverse shocks in the generation of broadband emission. Calculation results suggest that the very high efficiency of particle acceleration in Cas A, which value is up to 25% of the supernova explosion energy with energy of accelerated particles not exceeding of $��{10}^{14}�-�{10}^{15}�$ eV. Whereas, the forward shock model predicts the spectral characteristics of the TeV-gamma-emission corresponding to ones detected at 800 GeV–40 TeV that are the evidence of acceleration of the hadronic cosmic rays in shells of SNRs up to $��{10}^{17}�$ eV

The investigation of very high energy gamma-ray sources touches on the problem of the cosmic ray origin and the role of the Galaxy in their generation. The SHALON observations have yielded the results on $��\gamma �$Cygni SNR Galactic supernova remnant. The observation results are presented with spectral energy distribution and emission map by SHALON in comparison with other experiment data obtained by ROSAT in x-ray energy range, radio-data by CGPS, and also observations of GeV–TeV gamma-rays by Fermi LAT. The overall $��\gamma �$Cygni SNR characteristics detected in radio, x-rays, and GeV–TeV gamma-rays can be a result of the shocks at the interaction of the supernova ejecta and the surrounding medium. The collected experimental data help to make clear the origin of TeV $��\gamma �$-ray emission in the $��\gamma �$Cygni SNR. The density of target material in the SNR surroundings is enough to produce the observable TeV gamma-ray flux via the shock acceleration of hadrons in the detected regions. The detection of gamma-ray emission at 0.8–60 TeV from the North-West and South-East shells of $��\gamma �$Cygni SNR by SHALON would favor the hadronic origin of the gamma-rays in this supernova remnant.

Blazars are the subclass of active galactic nuclei (AGNs) which includes the Flat Spectrum Radio Quasars (FSRQ) and BL Lacertae (BL Lac) objects. Variability on the short- and long-time scale in all the wide energy ranges from radio up to gamma-ray emission is a special characteristic of blazars. Multi-wavelength studies of the flaring activity and variability of blazars can serve as a tool to probe the physical properties of the near the core regions and processes responsible for the observed features. 3C 454.3 is a bright FSRQ that is intensively studied through the wide range of electromagnetic spectrum. It has shown remarkably high activity since 2000. The long-term observations of 3C 454.3 at 800 GeV–100 TeV energies with the SHALON telescope were started in 1998 year. A number of activity periods were found. The most significant flaring state of 3C 454.3 at TeV energies was detected in the SHALON observational period of November–December 2010. This increase is correlated with the flares at a lower energy range in observations of Fermi-LAT. The direct association of the significant changes of gamma-ray flux with strong core radio flares are not clear but observed correlations and lags in multi-wavelength activity may point to the complexity of the emission processes in blazars connected with disturbance propagating in the jet.

Inferences are made about the relationship that existed between the Ushnus, pyramid-shaped, terraced structures used by the Incas in the most important ceremonies of the Tawantinsuyo, and Inka Astronomy. We draw attention to Ayni, Kawsaypacha, Duality, and Tinkuy principles, multidimensional codes of conduct and wisdom that are at the root of the Andean cosmovision and on their perception of the world and the Cosmos. These principles, examined as postulates, allow to elaborate axiomatic propositions to identify the Ushnus with ancient Astronomy practices. In a complementary statement, starting from a bi-conditional proposition, we may infer through reciprocal corollaries that the Inka earliest roots to a holistic learning and educational ambient in the Tawantinsuyo was not elitist, instead it was based on a epistemological construct that differs from the corresponding Western educational ambients. An epistemological and cognitive approach allows to identify an ancient elaborate process of knowledge construction, based on the four fundamental principles, corresponding to different levels of assimilation and comprehension. As a complementary aspect, we identify some of the most preserved Ushnus of the Inka “Empire.” Then we complement this contribution with a broader interpretation for the Ushnus.

RW Aurigae is a young stellar system containing a classical T Tauri star as the primary component. It shows deep, irregular dimmings, first detected in 2010. At the University Observatory Jena, we carried out optical follow-up observations. We performed multiband (BVRI) photometry of the system with the Cassegrain-Teleskop-Kamera II and the Schmidt-Teleskop-Kamera between September 2016 and April 2019, as well as spectroscopy, using the Fibre Linked ÉCHelle Astronomical Spectrograph between September 2016 and April 2018. We present the apparent photometry of RW Aur, which is consistent with and complementary to photometric data from the American Association of Variable Star Observers. The V-band magnitude of RW Aur changed by up to three magnitudes during the timespan of our monitoring campaign. For the observing epochs 2016/2017 and 2017/2018 we report a decreasing brightness, while in the epoch 2018/2019 the system remained in a relatively constant bright state. In the color-magnitude diagram, we see that RW Aur lies close to a track for grey extinction. The spectra show a decreasing equivalent width (EW) of the $��H�\alpha �$ emission line for decreasing brightness, whereas the EW of the $���\left[��O�I��\right]��$ line increases, indicating an increased outflow activity during the obscuration. Both give further evidence for the favored theory that the obscurations are caused by a hot dusty wind emerging from the inner disk.

We present relative astrometric and photometric measurements of visual double stars made in 2016–2017, with PISCO2 installed at the 76-cm refractor of Côte d'Azur Observatory in Nice (France). Our observing list contains orbital couples as well as double stars whose motion is still uncertain. Three different techniques were used for obtaining measurements: Lucky Imaging, Speckle Interferometry and the direct vector autocorrelation (DVA) method. From our observations of 1,510 multiple stars, we obtained 2,918 new measurements with angular separations in the range 0″.1–20″ and an average accuracy of $��0.019�$. The mean error on the position angles is 1°.1. Most of the position angles were determined without the usual 180° ambiguity with the application of the DVA technique and/or by inspection of the Lucky images or the long integration files. We managed to routinely monitor faint systems ($��m_V�\approx �9�-�12�$) with large magnitude differences (up to $��\Delta �m_V�\approx �4.5�$). We have thus been able to measure six systems containing red dwarf stars that had been poorly monitored since their discovery, from which we estimated the stellar masses thanks to Gaia measurements. We also measured the magnitude difference of the two components of 593 double stars with a mean error of 0.1 mag. Thanks to good seeing images and with the use of high-contrast numerical filters, we have also been able to obtain 46 measurements with an angular separation smaller than the diffraction limit of our instrumentation. Except for a few objects that have been discussed, our measurements are in good agreement with the ephemerides computed with published orbital elements, even for the double stars whose separation is smaller than the diffraction limit. We also report the measurements of 205 new double stars that we found in the files obtained during the observations.

This short paper gives a brief overview of the manifestly covariant canonical gauge gravity (CCGG) that is rooted in the De Donder-Weyl Hamiltonian formulation of relativistic field theories, and the proven methodology of the canonical transformation theory. That framework derives, from a few basic physical and mathematical assumptions, equations describing generic matter and gravity dynamics with the spin connection emerging as a Yang Mills-type gauge field. While the interaction of any matter field with spacetime is fixed just by the transformation property of that field, a concrete gravity ansatz is introduced by the choice of the free (kinetic) gravity Hamiltonian. The key elements of this approach are discussed and its implications for particle dynamics and cosmology are presented. New insights: Anomalous Pauli coupling of spinors to curvature and torsion of spacetime, spacetime with (A)dS ground state, inertia, torsion and geometrical vacuum energy, Zero-energy balance of the Universe leading to a vanishing cosmological constant and torsional dark energy.

Magnetars are a type of pulsars powered by magnetic field energy. Part of the X-ray luminosities of magnetars in quiescence have a thermal origin and can be fitted by a blackbody spectrum with the surface temperature, much higher than the typical values for rotation-powered pulsars. The persistent thermal emissions and bursts of magnetars indicate the presence of some internal heat sources in their outer crusts. In this work, we have formulated the energy balance equation and applied it to investigate the thermal evolution in the magnetar crust, taking into account the heating mechanisms of Ohmic decay and electron capture processes. This model can explain the changes in the X-ray luminosity of the magnetars.