Astrophysical Bulletin最新文献

{"title":"BTA Optical Telescope as Instrument for Millimeter Astronomy: Scientific Objectives","authors":"I. I. Zinchenko,&nbsp;V. A. Stolyarov,&nbsp;M. A. Tarasov","doi":"10.1134/S1990341325600723","DOIUrl":"10.1134/S1990341325600723","url":null,"abstract":"<p>During the period of 2023–2026, the scientists of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) are implementing a project to create a millimeter-wave observatory based on the BTA optical telescope. The project involves the installation of subterahertz receivers at the Nasmyth focus and the performance of test observations. This paper discusses scientific objectives that can be addressed both at the initial stage of the project using bolometric receivers for continuum observations and, in the future, using receiver systems based on HEMT and SIS technologies for molecular line observations.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"81 1","pages":"107 - 115"},"PeriodicalIF":1.4,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148021051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pre-Flare Energy Release Phases in the Eruptive X3.2 Solar Flare of May 14, 2013","authors":"I. N. Sharykin,&nbsp;I. V. Zimovets,&nbsp;N. S. Meshalkina","doi":"10.1134/S1990341325600280","DOIUrl":"10.1134/S1990341325600280","url":null,"abstract":"<p>This study is devoted to the investigation of pre-flare processes preceding the eruptive X3.2-class solar flare that occurred on May 14, 2013. This event was selected because of its favorable position near the solar limb, the presence of a well-pronounced pre-flare phase, and the availability of high-quality observed data from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA), Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), Nobeyama Radio Heliograph (NoRH), and Siberian Solar Radio Telescope (SSRT). The main objective of this work is to identify possible eruption triggers and to perform a detailed multiwavelength analysis of the pre-flare energy release properties. In this study, we consider a pre-flare time interval of about one and a half hours. From the point of view of temporal evolution, the pre-flare phase of the selected event consists of two stages. During the first stage, a quasi-stationary compact X-ray source is observed in the 5–25 keV energy range. The radio sources are also relatively stable, and their centroids coincide with the X-ray brightness center. This is followed by a sharp burst (nonthermal emission up to 100 keV is detected) and a subsequent increase in emission intensity over a broad spectral range. The observed sources become nonstationary. The second stage, following the burst, lasts for about one hour. During this period, the sources expand, and the growth of a coronal loop system is observed. Afterward, the eruption and the main flare take place. It is noteworthy that the trigger burst (TB) between the first and second pre-flare stages was associated with a very compact X-ray source and a strong brightening in all available ultraviolet (EUV and UV) channels. To determine the magnetic field structure at the photospheric level, vector magnetograms obtained by the Helioseismic and Magnetic Imager/Solar Dynamics Observatory (HMI/SDO) were used. These data showed that the pre-flare energy release and the TB were localized near the magnetic neutral line. Estimates of the thermodynamic parameters of the flare plasma, the energy of accelerated electrons, and the thermal energy of the pre-flare plasma were obtained based on the analysis of microwave and X-ray spectra. The observed microwave spectra are well explained by a gyrosynchrotron model consisting of an extended source associated with high coronal loops and the plasma temperature <span>(Tapprox 5{-}7)</span> MK, a compact source in lower loops (<span>(Tapprox 10{-}20)</span> MK), and bremsstrahlung emission at frequencies of 17–34 GHz. In general, the X-ray data from the compact source are in good agreement with the observed radio emission.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"81 1","pages":"116 - 145"},"PeriodicalIF":1.4,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148021055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Search and Study of Variable Stars in Selected Fields with the Small Photometric Telescope of the CMO SAI MSU","authors":"A. V. Samokhvalov","doi":"10.1134/S1990341325600681","DOIUrl":"10.1134/S1990341325600681","url":null,"abstract":"<p>During the implementation of the program of photometric studies of variable stars, 215 variable stars were studied in selected fields. Variability parameters were refined for 48 of them, and variability was discovered and studied for the first time for 42 of them. A description of the Small Photometric Telescope, installed in the 4th pavilion of the Caucasian Mountain Observatory (CMO) of the Sternberg Astronomical Institute of Moscow State University (SAI MSU), is provided. Particular attention is given to the installed instruments and technical aspects of the observation organization.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"81 1","pages":"68 - 82"},"PeriodicalIF":1.4,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148021049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase-Resolved Spectroscopy of the Polar V379 Vir with a Brown Dwarf","authors":"M. V. Suslikov,&nbsp;A. I. Kolbin,&nbsp;N. V. Borisov","doi":"10.1134/S1990341325600693","DOIUrl":"10.1134/S1990341325600693","url":null,"abstract":"<p>The polar V379 Vir is a well-known magnetic cataclysmic variable with a brown dwarf donor. Despite numerous studies of this system across various spectral ranges, a detailed investigation of the orbital variability of its optical spectra has not been carried out. In this work, we present an analysis of spectroscopic observations of V379 Vir obtained with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. The orbital variability of the H<span>(alpha)</span> emission indicates that the line is most likely formed in the accretion stream near the Lagrangian point <span>(L_{1})</span>, rather than on the donor’s surface, as previously assumed. The analysis of the rotational variability of the Zeeman splitting of hydrogen lines reveals a complex magnetic field topology of the white dwarf, which differs from a simple dipole configuration.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"81 1","pages":"44 - 53"},"PeriodicalIF":1.4,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148021054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dust Envelope around the Carbon Star RW LMi","authors":"A. A. Vakhonin,&nbsp;B. S. Safonov,&nbsp;I. A. Strakhov,&nbsp;A. M. Tatarnikov,&nbsp;V. I. Shenavrin","doi":"10.1134/S199034132560067X","DOIUrl":"10.1134/S199034132560067X","url":null,"abstract":"<p>Results of infrared photometric observations of RW LMi in the <span>(JHKLM)</span> bands are presented. The observations were carried out from 1994 to 2024. Based on the observations of 17 pulsation cycles of the star, new brightness ephemerides were established: <span>({textrm{JD}}_{textrm{max}}=2459677overset{textrm{d}}{.}0+610overset{textrm{d}}{.}9,E)</span>. A sinusoidal trend of the average brightness level was found. Its period is about 7300 days and its amplitude is approximately <span>(1^{textrm{m}})</span> in the <span>(JHK)</span> bands. From the energy distribution in the spectrum in the wavelength range of 0.5–100 <span>(mu)</span>m, an estimate of the bolometric flux at the maximum brightness was obtained: <span>(F_{textrm{bol}}=2.6times 10^{-6})</span> erg s<span>({}^{-1})</span> cm<span>({}^{-2})</span>. This corresponds to the luminosity <span>(L_{textrm{max}}approx 8500;L_{odot})</span>. Modeling the RW LMi circumstellar envelope radiation was performed with the <span>RAMDC-3D</span> program. The simulation was carried out in the approximation of a spherically symmetric envelope shape with a constant mass-loss rate. The main envelope parameters are: the optical depth <span>(tau_{V}approx 12.7)</span>, the inner radius <span>(R_{textrm{in}}approx 8)</span> AU, the outer radius <span>(R_{textrm{out}}approx 17,000)</span> AU, and the mass-loss rate <span>(dot{M}=6times 10^{-6}M_{odot})</span> yr<span>({}^{-1})</span>.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"81 1","pages":"54 - 67"},"PeriodicalIF":1.4,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148021048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Motion of Open Star Clusters in the Galaxy According to Gaia DR3 data","authors":"V. M. Danilov,&nbsp;M. E. Popova","doi":"10.1134/S1990341325600711","DOIUrl":"10.1134/S1990341325600711","url":null,"abstract":"<p>The paper estimates the average components of the velocities <span>(V_{R})</span>, <span>(V_{theta})</span>, <span>(V_{z})</span>, specific kinetic energies <span>(T_{k})</span>, and dispersions <span>(sigma_{V}^{2})</span> of the velocities of open star clusters (OSCs) in the solar neighborhood based on the Gaia DR3 data. The dependences of the dispersions of the <span>(T_{k})</span> values and the velocities of the open-clusters on the distance <span>(R)</span> of the clusters to the Galactic rotation axis are constructed. A number of local maxima and minima in these dependences are noted. Numerical modeling of the trajectories of the OSC motions in the force field of the axisymmetric part of the Galaxy (the three-component model of Miyamoto, Nagai) and a four-armed spiral pattern was performed. Comparison of the values <span>(T_{k})</span>, the amplitudes of <span>(T_{k})</span> oscillations and the cylindrical galactocentric coordinates (<span>(R,theta,z)</span>) of the OSCs with time and kinematic data on the motion of clusters results in estimating the ratio of the potentials of the spiral arms and the axisymmetric part of the Galaxy <span>(Q=0.0010{-}0.0012)</span>. Within the framework of the considered model of the Galaxy, the following was obtained: (1) the ratio of the disk mass to the total mass of the three components of the Galaxy (in the range of distances from its center from 0 to <span>(r)</span>) equal to <span>(0.4)</span> is achieved with <span>(r=r_{b}simeq 14.69)</span> kpc; (2) the contribution of the halo potential to the total potential of the Galaxy is equal to 0.778, 0.708, and 0.667 with <span>(r=r_{b})</span>, 9, and 7 kpc, respectively. In this range of <span>(r)</span> values, the influence of the halo on the motion of OSCs in the Galaxy is approximately three times greater than the influence of the disk. Therefore, radial oscillations of the halo can make a significant contribution to the motion of OSCs in the Galaxy; (3) a formula for the frequency of small oscillations of the halo was obtained, the period of such oscillations is <span>(7.135times 10^{9})</span> yrs; (4) a formula for the free-fall time <span>(tau_{textrm{ ff}})</span> of a star from a distance <span>(r_{0})</span> to the halo center was obtained; (5) using <span>(tau_{textrm{ff}})</span> and the data obtained in 2022 by Bird et al. on the velocities <span>(sigma_{V})</span> of Galactic halo stars, an estimate of the Jeans radius was obtained for the halo: <span>(r_{J}=26.7^{+4.1}_{-2.9})</span> kpc. For the central part of the Galaxy, enclosed within a sphere of the radius <span>(r_{0}=35)</span> kpc, using <span>(tau_{textrm{ ff}})</span> from our 2024 work for a homogeneous gravitating sphere, we obtained the estimate <span>(r_{J}=33.83pm 1.41)</span> kpc indicating the gravitational instability of regions of the Galaxy with the distances <span>(r)</span> from <span>(r=0)</span> to <span>(r&gt;r_{J})</span>.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"81 1","pages":"23 - 43"},"PeriodicalIF":1.4,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148021053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compact Formulation for Numerical Solution of Chandrasekhar’s (boldsymbol{H})-Function","authors":"H. Öztürk,&nbsp;F. Anlı,&nbsp;A. Kadem","doi":"10.1134/S1990341325600450","DOIUrl":"10.1134/S1990341325600450","url":null,"abstract":"<p>Chandrasekhar’s <span>(H)</span>-function plays an important role in applied sciences, such as radiative transfer scattering theory. In this paper a numerical solution of the nonlinear integral equation for Chandrasekhar’s <span>(H)</span>-function and its first derivative has been derived. In addition, numerical results for the zeroth, first, and second moments of the <span>(H)</span>-function are obtained. We have arranged a compact formulation for the Gauss-shifted Legendre quadrature set and used it for numerical computation. It can be seen from the derivation of the equations and application of the numerical method explained in detail that the present method can be applied to other problems in applied sciences. Numerical results consistent with those available in the literature have been obtained even in low-order approximations. Accordance between them corresponds to a difference of about 0.01<span>(%)</span>. This explicitly illustrates the accuracy and capability of the method.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"80 4","pages":"703 - 709"},"PeriodicalIF":1.4,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MOLLId: Software for Automatic Identification of Molecules and Its Application to the Spectra of Protostars from the Region RCW 120","authors":"A. A. Farafontova,&nbsp;M. S. Kirsanova,&nbsp;S. V. Salii","doi":"10.1134/S1990341325600498","DOIUrl":"10.1134/S1990341325600498","url":null,"abstract":"<p>In this work, we present the program <span>MOLLId</span> (MOLecular Line Identification) for automated molecular line approximation with a Gaussian profile. Molecular identification was performed using multi-level comparison of the lines’ center frequencies and rest frequencies from the spectroscopic database. The program was tested in the identification of molecular lines in observed spectra of young stellar objects RCW 120 YSO S1 and RCW 120 YSO S2 located near the border of the RCW 120 PDR. In the spectra of the RCW 120 YSO S1 source, 100 lines of 41 molecules were identified over the level of 4–6 <span>(sigma)</span>. In the spectra of the RCW 120 YSO S2 source, 407 lines of 79 molecules were identified over the 3–5 <span>(sigma)</span> level. Using the Intel Core i7-12700K CPU, identification time is equal to 6 and 8 minutes per spectral range for the YSOs S1 and S2, respectively. From the analysis of CH<span>({}_{3})</span>OH, CH<span>({}_{3})</span>CN, CH<span>({}_{3})</span>CCH molecules identified in RCW 120 YSO S2, we found a two-component structure and estimated the physical parameters in the LTE approximation for each of the components.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"80 4","pages":"645 - 669"},"PeriodicalIF":1.4,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methods for Analyzing Multiwavelength Light Curves of AGNs","authors":"M. L. Khabibullina,&nbsp;V. A. Stolyarov,&nbsp;P. G. Zhekanis,&nbsp;T. V. Mufakharov,&nbsp;Yu. V. Sotnikova,&nbsp;A. E. Volvach,&nbsp;G. A. Borman,&nbsp;T. S. Grishina,&nbsp;E. G. Larionova,&nbsp;D. A. Morozova,&nbsp;S. S. Savchenko,&nbsp;I. S. Troitskiy,&nbsp;Yu. V. Troitskaya,&nbsp;A. A. Vasilyev","doi":"10.1134/S1990341325600589","DOIUrl":"10.1134/S1990341325600589","url":null,"abstract":"<p>The paper presents methods for analyzing multiwavelength light curves of active galactic nuclei with uneven time sampling, including the use of the structure functions, autocorrelation and cross-correlation functions, Lomb–Scargle periodograms, and weighted wavelet analysis. The structure functions allow quantitative estimation of the temporal scales of variations, correlation functions provide detection of temporal delays between different frequencies, Lomb–Scargle periodograms detect periodicities in nonuniform data, and wavelet analysis makes it possible to localize variable processes in time and to study the evolution of the signal frequency composition. The comprehensive use of these methods allows detailed investigation of the temporal and frequency structure of physical processes in active galactic nuclei, taking into account the influence of the unevenness of experimental data. The advantages and limitations of each method are considered using examples of analyzing specific sources, and their practical significance for studying the variability of active galactic nuclei is demonstrated.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"80 4","pages":"678 - 702"},"PeriodicalIF":1.4,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Averaged Phase Curves for Several Taxonomic Types of Asteroids","authors":"T. A. Vinogradova","doi":"10.1134/S1990341325600516","DOIUrl":"10.1134/S1990341325600516","url":null,"abstract":"<p>A method is proposed for constructing averaged phase curves of asteroid brightness for various taxonomic types. The method is based on a large number of astrometric observations published in the Minor Planet Center catalog, for which the apparent visual magnitudes of asteroids were measured simultaneously. Thousands of asteroids of each taxonomic type S, C, E, V, Q, L, D, and X were selected, and numerical integration of the equations of motion was performed. In the course of integration, for each observation, the component of the apparent magnitude dependent on the phase angle was determined. For asteroids of a given type, all obtained values were averaged over the phase angle. As a result, averaged phase curves characterizing each taxonomic type were constructed. The large volume of observational data makes it possible to clearly reveal the character of the opposition effect for different types. A shift of the phase curves with respect to zero at a zero phase angle was noted. This shift depends on asteroid size and differs among taxonomic types. The presence of such a shift indicates a systematic error in the absolute magnitudes of asteroids published in the Minor Planet Center catalog.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"80 4","pages":"670 - 677"},"PeriodicalIF":1.4,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}