Issue 1, 2026
Research on vibration resistance of fiber and solid-state lasers
Research on vibration resistance of fiber and solid-state lasers
A. Yu. Danilov$^{1,2}$, G. Yu. Ivanov$^{1,3}$, E. A. Fomiryakov$^1$, A. V. Reznikov$^1$
Phase-frequency stability degradation under mechanical vibrations was characterized for single-frequency high-coherence fiber and semiconductor lasers. Vibration sensitivity showed strong dependence on both laser type (diode vs. fiber) and spatial orientation, with semiconductor devices demonstrating greater vibration resistance.
Show AbstractPhotosystem 2 protein PsbS is a component of the molecular mechanism of non-photochemical quenching in green algae
Photosystem 2 protein PsbS is a component of the molecular mechanism of non-photochemical quenching in green algae
V. V. Ptushenko$^{1,2}$
The energy transfer of chlorophyll excited state during photosynthesis and electron transfer along the photosynthetic electron transport chain are the central processes of light energy conversion into chemical energy while also the sources of potential danger to the organism. Non-photochemical quenching (NPQ) of chlorophyll excited states is one of the key mechanisms for protecting the photosynthetic apparatus from the dangerous effects of excessive light energy. The main molecular components of NPQ are oxygen-containing carotenoids, xanthophylls, as well as proteins: a photosystem 2 component PsbS and its algal analogue, the LhcSR/LHCX protein. Previously, PsbS was believed to be typical only for higher plants, while in algae it should not be expressed or at least play any significant role in NPQ. Later it became clear that its expression is stress-induced, but it took place in a too short timescale. This led to an assumption that its protective role was limited only by an auxiliary role in transients. However, we have recently found long-term stress-induced expression of its gene in one of the of green algal species. In this paper, we attempted to expand the range of analyzed species and show that long-term stress-induced expression of PsbS (which could be indicative of its protective function) can be widespread among green algae. The variability of PsbS primary structure in green algae was also studied, which, in turn, is considered to correlate with the importance of protein functions for an organism.
Show AbstractG106.6+2.9 Spectrum
G106.6+2.9 Spectrum
U. M. Starodubtceva
The Boomerang Nebula G106.6+2.9 is one of the candidates for the sources of ultrahigh energy cosmic rays. The source under consideration is a spatially extended system of the pulsar PSR J2229+6114 and the surrounding pulsar wind nebula, which has a characteristic comet-like shape. At present, there are many papers devoted to the spectrum of the tail region of this nebula. However, the head region is also interesting. This topic is not so widely covered. This paper presents the energy spectra of the tail and head regions, discusses a feature in the spectrum of the head region, recorded by the Comptel, EGRET and COS-B experiments.
Show AbstractSkyMapMod: A python numerical model of the night sky brightness in the optical range
SkyMapMod: A python numerical model of the night sky brightness in the optical range
A. A. Amineva$^{1,2}$, D. A. Podgrudkov$^{1,2}$
In this work, we present a numerical model of the night sky brightness in the optical range called SkyMapMod, intended for ground-based astrophysical experiments that rely on the detection of optical radiation (such as fluorescence and gamma-ray telescopes, and Cherenkov detectors of extensive air showers). The model predicts the photon flux spectrum from a selected region of the sky for a specified location and observation time. It accounts for stars and diffuse galactic and extragalactic sources, atmospheric airglow, zodiacal light, and light from solar system planets. The propagation of light through the atmosphere is also modeled.
Show AbstractCalibration of the TAIGA-IACT imaging Camera with a nanosecond pulsed LED light source
Calibration of the TAIGA-IACT imaging Camera with a nanosecond pulsed LED light source
A. T. Panfiorova$^1$, N. B. Lubsandorzhiev$^2$, E. E. Korosteleva$^2$
The imaging atmospheric Cherenkov telescopes of the TAIGA-IACT experiment are part of the TAIGA (Tunka Advanced Instrument for cosmic rays and Gamma Astronomy) astrophysical complex. Each TAIGA-IACT telescope is equipped with a segmented mirror in the Davis-Cotton design with a diameter of 4.3 m. An imaging camera is installed in the focal plane of the telescope, consisting of approximately 600 photomultiplier tubes (PMTs) with a photocathode diameter of 15 mm. The imaging cameras of the atmospheric Cherenkov telescopes require regular calibration of the PMT parameters and the electronic readout chains to ensure the reliability of experimental data. This work describes the methods used to calibrate the PMTs and the readout channels of the imaging camera of the third TAIGA-IACT atmospheric Cherenkov telescope. The conversion factors from ADC counts to the number of photoelectrons, as well as the relative quantum sensitivity coefficients of the PMTs, were obtained using a nanosecond light source during a calibration carried out in March 2024.
Show AbstractSpectral analysis of long gamma-ray bursts as an instrument to investigate the early Universe
Spectral analysis of long gamma-ray bursts as an instrument to investigate the early Universe
A. S. Nikulina$^{1,2}$
This paper presents an analysis of the spectrum of the long and bright gamma-ray burst GRB 180720B with the aim of identifying features in the spectral region associated with nuclear resonances. The resonant gamma-ray absorption method (GRAM) is applied to investigate these features, accounting for the possible presence of absorbers along the line of sight between the GRB source and the observer. The resulting spectral energy distribution indicates the presence of an absorption-like feature around 300 MeV. Based on previous studies of gamma-ray interactions with matter, we suggest that the observed feature may correspond to the delta-resonance, either scattered by one or multiple intervening absorbers, or represented a blend of two separate absorption lines at different energies, merged due to spectral broadening effects.
Show AbstractA system of local criteria for separating EAS by primary particle masses based on the lengths of the major axis of images in the Cherenkov light angular distribution detector of the SPHERE-3 facility
A system of local criteria for separating EAS by primary particle masses based on the lengths of the major axis of images in the Cherenkov light angular distribution detector of the SPHERE-3 facility
O. V. Cherkesova, V. I. Galkin
The planned SPHERE-3 installation, unlike the SPHERE-2 installation, will have not only a telescope of reflected Cherenkov light, but also a detector that records the angular distribution of direct Cherenkov light. In this paper, the length of the major axis of the Cherenkov image is considered as a parameter sensitive to the mass of the primary particle. A method for estimating the mass of a primary particle based on the length of the major axis of the Cherenkov image has been improved, and a method for classifying primary particles based on data from direct and reflected light detectors has been created.
Show Abstract