Astrophysical Bulletin最新文献

The flux density spectra of cyclotron sources above the sunspotswere obtained by observations with RATAN-600 in the range of1.7–10 cm with high spectral ((Delta f/fsim 1{-}5%))resolution and their spectral indices were estimated. The spectralindex was then utilized to determine the magnitude of themagnetic field at the base of the transition region on the Sun. Byanalyzing the relationship between theemisson flux density of the sources and the magnetic fieldit was found that the observed characteristics ofsunspot-associated sources did not align with predictions from asimplified radiation model commonly used for data interpretation.Specifically, there was an excess flux density in the spectrum ofordinary mode radiation compared to what was expected.

The article discusses the prospects for developing the observational base at the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) for astrophysical research in the millimeter-wave range. As a first step, a project is proposed to create a set of sub-terahertz receiving equipment to operate at the optical BTA telescope. Additionally, the possibility of installing a new instrument to operate in the frequency range of up to 230 GHz ((lambda=1.3) mm) at the Upper Research Site of SAO RAS is considered. Technical and operational characteristics of the instrument, site selection for the installation of a fully steerable millimeter-wave antenna, statistics of meteorological data and atmospheric absorption are discussed. A list of potential scientific tasks addressed by instruments of this class is provided.

Based on the fluxes of 1400 nearby galaxies observed in far ultraviolet (FUV) and in the H(alpha) line, we determined the global star formation rate per unit Universe volume, (j_{textrm{SFR}}=(1.34pm 0.16)times 10^{-2}M_{odot}) yr({}^{-1}) Mpc({}^{-3}). With the current star formation rate (({SFR})), ((65pm 4)%) of the observed stellar mass is reproduced in the cosmological time of 13.8 billion years. The neutral gas reserves in the Local Volume with a radius of 11 Mpc will facilitate the current ({SFR}) on a scale of approximately another 5 billion years.

The results of photometric and spectroscopic observations of supernova SN 2022prv carried out with six telescopes including the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences and the 2.5-m telescope of the Caucasus Mountain Observatory of SAI MSU are presented. The dates and magnitudes at the brightness maximum and the parameters of the light curves are determined. The photometric evolution of SN 2022prv is characterized by a constant decrease in brightness after the maximum at a rate quite high for a type II supernovae. Approximately 55 days after the maximum, the rate of the decrease in brightness increased. The maximum luminosity has reached (M_{V}=-18overset{textrm{m}}{.}1) which is higher than average for SN II. In the pre-maximum spectra, high-excitation emission lines were observed characteristic of the ionization of the circumstellar matter by a burst during the shock wave emergence onto the surface of the star. However, approximately 20 days after the maximum, the spectrum did not differ from that typical of SN II. The rate of the envelope expansion at this stage was about 3500 km s({}^{-1}) which is a little smaller than average for SN II values.

In this paper, the phenomenon of lopsidedness associated with the observed effect of displacement of the core of a spiral galaxy from its geometric center is explained by the gravitational instability of individual perturbation modes. The main ones are perturbation modes with radial wave numbers (N=3) and (N=5), where the azimuthal index is (m=1). Unlike other authors, we studied the lopside instability phenomenon against the background of a non-stationary model of a nonlinearly pulsating disk. The mechanisms and criteria for the origin of the phenomenon of displacement of the core in spiral galaxies are revealed. In addition, to determine the dependence of this effect on the geometry of the gravitating system, we also carried out an analysis of lopsided perturbation modes in the framework of a spherical nonstationary model.

A differential image motion monitor (DIMM) has been developed and manufactured to study atmospheric seeing. The monitor is made in a lightweight field version and can operate without a telescope, as has always been the case before. Two apertures are made using 70-mm lenses with a focal distance of 900 mm. The distance between the aperture axes is 300 mm. The images from the apertures are combined in the plane of a single CMOS camera operating at up to 314 frames per second speed with low reading noise of about (3e^{-}). The device also includes a (3^{circ}!times!3^{circ}) field of view viewer for pointing at a star. The monitor proved to work successfully during several astroclimate study expeditions. The monitor data were verified by comparing them with the results of atmospheric seeing measurements at the 2.5 meter telescope of the Caucasian Mountain Observatory.

This work is a continuation of the work of Kopylova and Kopylov published in 2016 on constructing the fundamental plane (FP) of groups and clusters of galaxies. In this article, the sample of galaxy systems has been increased from 94 to 172 objects. We have studied the relationships between the main characteristics of groups and clusters of galaxies using archival data from the SDSS, 2MASX, and NED catalogs. The measured parameters ((log L_{K}), (log R_{e}) and (logsigma)) of galaxy clusters define the fundamental plane in the near-infrared region: (L_{K}propto R_{e}^{0.77pm 0.09}sigma^{1.44pm 0.12}). The shape of the FP of groups and clusters is consistent with the FP of early-type galaxies (SDSS, (r)-filter), determined in the same way. Regression against (log R_{e}) in kpc gives the projection of the FP: (log R_{e}=0.98(pm 0.06),logsigma-0.56(pm 0.04)langlelog I_{e}rangle+3.57(pm 0.07)), which can be used to determine the distances of galaxy systems. The (rms) scatter of the zero point is 0.07, which is equivalent to a 16(%) error in determining the distance to a group or cluster of galaxies. For the first time, we have determined the average relative FP distances and peculiar velocities of five large superclusters of galaxies. According to our estimates, the average peculiar velocity of these superclusters relative to the CMB is (+75pm 360) km s({}^{-1}).

The light curves for almost 50 thousand stars with magnitudes (min[11overset{textrm{m}}{.}5,19overset{textrm{m}}{.}5]) have been obtained over 2.5 years at SAO RAS in the process of conducting an exoplanet survey in roughly (1overset{circ}{.}5)-sized fields around the white dwarfs WD 0009(+)501 and GRW (+)708247. In this paper we present a catalog of variable stars that have been found in the considered regions. Periodogram analysis was used as the main variation search method. The catalog includes 150 periodic variable stars: 113 of them have been known previously, and for the remaining 37 variations have been discovered for the first time. These stars were classified according to the nature of the variations into four eclipsing variable and three pulsating types, as well as rotating stars. We present the periods and variation amplitudes in the range of (Pin[0overset{textrm{d}}{.}036,32overset{textrm{d}}{.}14]) and (Delta min[0overset{textrm{m}}{.}0064,1overset{textrm{m}}{.}45]), determined from the investigated data.

The problem caused by the inconsistency between the age and spin-down time scale of the white dwarfs in the systems AR Sco and AE Aqr is discussed within the hypothesis of their accretion-driven spin-up during the previous epoch. Considering a scenario of accretion from a Keplerian disk, we conclude that the white dwarfs in these systems could be spun-up to the currently observed periods provided the radius of their magnetospheres at the spin-up phase was substantially smaller than the Alfven radius. We show that the required magnetospheric radius value can be reached if the accretion flow penetrates the magnetic field of the white dwarf at its magnetospheric boundary due to anomalous (Bohm) diffusion. In this case the spin-up of the white dwarfs in the systems under consideration can be described based on a model of stationary accretion from the Keplerian disk at an average rate of (10^{-9}{-}10^{-8}M_{odot}) yr({}^{-1}) without any additional assumptions about the evolution of the intrinsic magnetic field of the white dwarfs during the spin-up phase.

The article presents the results of long-term photometric monitoring of two binary gravitationally lensed quasars, SDSS J2124(+)1632 and SDSS J0806(+)2006, carried out at the Maidanak Observatory in 2017–2022. The obtained light curves of the lensed components of both systems are analyzed. The variability of SDSS J2124(+)1632 turned out to be quite large: up to (0overset{textrm{m}}{.}50) for the system as a whole and up to (0overset{textrm{m}}{.}75) for component A. Long-term microlensing was found against the background of a general increase in the apparent brightness of the quasar source. The brightness variations in SDSS J0806(+)2006 are less intense: the range is about (0overset{textrm{m}}{.}20) for the system as a whole, and up to (0overset{textrm{m}}{.}25) for both components. Analysis of the light curves did not show the presence of microlensing here. We also calculated the probable values of the time delay: (Delta t_{textrm{AB}}=102pm 20) days (component B is in the lead) and (Delta t_{textrm{AB}}=-53.0pm 6.0) days (component A is in the lead) in SDSS J2124(+)1632 and SDSS J0806(+)2006, respectively. The value of (Delta t_{textrm{AB}}) for SDSS J2124(+)1632 is consistent with previously found time delays for binary gravitationally lensed systems. In the case of the second system, the time delay is consistent with earlier theoretical calculations, which suggested that the time delay should be about 50 days.