Astrophysical Bulletin最新文献

Abstract—The design and functions of the main component of the automated complex for the study of astrophysical objects with high time resolution at the 6-m telescope of SAO RAS—a permanently available photopolarimeter installed at the N1 focus of the BTA for alert observations of optical transient sources are described. The device operates in several modes (up to six in perspective)—spectral, polarimetric, photometric, the choice of which is determined after real-time analysis of the image of the object localization area, recorded in the subview with a field of view of (2mathop .limits^prime 5 times 3'). The radiation from the vicinity of the detected source is transferred to a diaphragm of variable size from (10'' times 10'') to (60'' times 10'') and, depending on its brightness, passed through one of the (UBVR) filters or dispersed by the Abbe prism, is recorded by the EMCCD with a time resolution of 0.1 s. In this case, it is possible to introduce a double Wollaston prism into the input beam, which ensures the measurement of the object’s linear polarization. To compensate for the rotation of the instrument’s field of view during observations on the balcony of the N1 focus, a turntable is used, the position of which is set by the telescope’s control system. Control of the observation process, selection and change of modes is carried out using a graphical interface. The automatic implementation of these operations is being tested.

Abstract—We present new results of the study of ET Dra—a star of the FK Com type—based on observations carried out at the Zvenigorod Observatory of the Institute of Astronomy of RAS with the help of the FRAM-ORM telescope of the La Palma observatory (Spain) and the broadband optical monitoring system Mini-MegaTORTORA, located on the territory of the SAO RAS. We have studied changes in the shape of the light curve caused by the rotational modulation of a star with spots on its surface and the long-term variability of the star’s brightness. An independent determination of the rotation period of ({{P}_{{{text{phot}}}}}) was carried out using all sets of observations available to us. The increase in the brightness of the star near HJD 2459044 during observations with the FRAM-ORM telescope in all three filters was interpreted by us as a stellar flare. Our flare energy estimates are (2.8 times {{10}^{{37}}}), (1.9 times {{10}^{{37}}}), and (1.5 times {{10}^{{37}}}) erg in the (B), (V), and (R) wavelength ranges, respectively. Observations with a duration of more than 2200 days, carried out at the SAO RAS, opened up the possibility of analyzing the long-term brightness variability of ET Dra. Evidence was found for the existence of cycles lasting 580 days and 810 days (1.55 and 2.23 years, respectively).

Abstract—We undertook a search for new dwarf galaxies in the vicinity of relatively isolated nearby galaxies with distances (D < 12) Mpc and stellar masses in the ((2 times {{10}^{{11}}})–(3 times {{10}^{8}} {{M}_{ odot }})) interval, using the data from the DESI Legacy Imaging Surveys. Around the 46 considered Local Volume galaxies, (67) new candidates for satellites of these galaxies were found. About half of them are classified as spheroidal dwarfs of low surface brightness. The new galaxies are included in the Local Volume database (LVGDB), which now contains 1421 objects, being 63% more than the Updated Nearby Galaxy Catalog.

Abstract—We present the first part of the survey of the results of spectroscopic observations of mirides in the optical and near infrared ranges. The main phenomenological schemes and models are listed. The published results are supplemented by spectroscopic observations and calculations performed at the SAO RAS.

Abstract—We describe a new wide-field GPIXEL 9 K ( times ) 9 K, CMOS and compare it with foreign-made chips of similar size. We report the parameters of the advanced NEVA9090 wide-field detector based on this CMOS and manufactured by NPK Fotonika. The camera can be used as a detector for modern high-performance wide-field telescopes. We present the parameters of a telescope with an aperture of 1 m and a focal ratio of (F:1.3) when operated with the new NEVA9090 camera.

We report the results of a study of the distribution of galaxies in the projection along the radius ((R leqslant 3{{R}_{{200{text{c}}}}})) for 157 groups and clusters of galaxies in the local Universe (0.01 < (z) < 0.10) with line-of-sight velocity dispersions 200 < (sigma ) < 1100 km s^–1. We introduce a new observed boundary for the halos of clusters of galaxies, which we identify with the splashback radius ({{R}_{{{text{sp}}}}}). We also identified the core of groups/clusters of galaxies with the radius ({{R}_{{text{c}}}}). These radii are determined by the observed integrated distribution of the number of galaxies as a function of squared angular radius from the center of the group/cluster, which (usually) coincides with the brightest galaxy. We found for the entire sample that the boundary of dark matter ({{R}_{{{text{sp}}}}}) for groups/clusters of galaxies is proportional to the radius ({{R}_{{{text{200}}}}}) of the virialized region. We measured the mean radius (langle {{R}_{{{text{sp}}}}}rangle = 1.14 pm 0.02) Mpc for groups of galaxies ((sigma leqslant 400) km s^–1) and (langle {{R}_{{{text{sp}}}}}rangle = 2.00 pm 0.07) Mpc for clusters of galaxies ((sigma > 400) km s^–1). The mean ratio of radii is (langle {{{{R}_{{{text{sp}}}}}} mathord{left/ {vphantom {{{{R}_{{{text{sp}}}}}} {{{R}_{{{text{200c}}}}}}}} right. kern-0em} {{{R}_{{{text{200c}}}}}}}rangle = 1.40 pm 0.02), or (langle {{{{R}_{{{text{sp}}}}}} mathord{left/ {vphantom {{{{R}_{{{text{sp}}}}}} {{{R}_{{{text{200m}}}}}}}} right. kern-0em} {{{R}_{{{text{200m}}}}}}}rangle = 0.88 pm 0.02).

Abstract—The article provides a brief description of the software package DECH for processing and analysis of astronomical spectra. DECH supports all stages of processing and analysis of spectral data, including image preprocessing, spectra extraction (including those with a variable tilted slit), wavelength calibration by a two-dimensional polynomial, continuum normalization (manual or automatic), measurement of equivalent widths and radial velocities in various ways, cross-correlation analysis, etc. The DECH software package is actively used by astronomers from different countries and continues to be improved. In particular, utilities for processing and analysis of data from the high-resolution fiber-feed echelle spectrograph installed at 6-m telescope of Special Astrophysical Observatory of Russian Academy of Sciences were added in the latest version. Software provides high-precision measurements of radial velocities, including those for detection of extraterrestrial planets.

Abstract—We present a review of the papers written in the research field of stellar magnetism in 2021. The instruments, observation, and data analysis methods, photometry, spectroscopy, and spectropolarimetry results are considered. We present new data on magnetic fields of chemically peculiar stars and other objects of various types.

Abstract—The new observational data concerning distribution, excitation, and kinematics of the ionized gas in the giant early-type galaxy NGC 2655 obtained at the 6m telescope of the Special Astrophysical Observatory (SAO RAS) and at the 2.5 m telescope of the Caucasian Mountain Observatory (CMO SAI MSU) are presented in this work. The joint analysis of these and earlier spectral observations has allowed us to make a conclusion about multiple nature of the gas in NGC 2655. Together with a proper large gaseous disk experiencing regular circular rotation in the equatorial plane of the stellar potential of the galaxy for billions years, we observe also remnants of a merged small satellite having striked the central part of NGC 2655 almost vertically for some 10 million years ago.