Search

During the first all-sky survey of the SRG orbital observatory, the X-ray source SRGE J170245.3+130104 was discovered with the eROSITA telescope on March 13–15, 2020. Its optical counterpart was identified by photometric attributes as a candidate for distant quasars at $$z\approx 5.5$$ . The spectroscopic observations of the object carried out in August and September 2020 at the 6-m BTA telescope with the SCORPIO-II instrument confirmed that SRGE J170245.3+130104 is a quasar at redshift $$z_{\textrm{{spec}}}=5.466\pm 0.003$$ . According to the eROSITA data obtained during the first sky survey, the X-ray luminosity of the quasar is $$3.6^{+2.1}_{-1.5}\times 10^{46}$$ erg s $${}^{-1}$$ in the 2–10 keV energy band, while its X-ray spectrum can be approximately fitted by a power law with a slope $$\Gamma=1.8^{+0.9}_{-0.8}$$ . The quasar was detected again with the eROSITA telescope half a year later (on September 13–14, 2020) during the second sky survey, with its X-ray luminosity, probably, having decreased approximately by a factor of 2 at a confidence level $${\approx}1.9\sigma$$ . SRGE J170245.3+130104 has turned out to be the most X-ray luminous quasar among all of the known quasars at redshifts $$z>5$$ . At the same time, it is also one of the radio loudest distant quasars (radio loudness $$R\sim 10^{3}$$ ), which may imply that this is a blazar. We present a catalog of all the quasars at $$z>5$$ detected in X-rays to date.

We present the first results of our program of optical observations for galaxy clusters from the Lockman Hole X-ray survey with the eROSITA telescope onboard the SRG space observatory. We present the results of spectroscopic redshift measurements for 11 galaxy clusters that have been identified optically among the extended X-ray sources of the SRG/eROSITA survey using data from optical and infrared sky surveys. The spectroscopic observations were carried out in late 2019–early 2020 with the 1.6-m AZT-33IK telescope of the Sayan Observatory and the 6-m SAO RAS telescope (Bolshoi Teleskop Azimutalnyi, BTA).

We present the results of spectroscopic redshift measurements for galaxy clusters from the catalogue compiled previously from Planck all-sky survey data in combination with Sloan Digital Sky Survey (SDSS) and WISE data in the optical and infrared ranges. Most of these clusters are massive objects that will also be detected in future all-sky surveys, such as the eROSITA all-sky X-ray survey onboard the Spectrum–Roentgen–Gamma (SRG) space observatory. The spectroscopic observations of these galaxy clusters have been carried out with the 1.5-m Russian–Turkish telescope (RTT150), the 1.6-m Sayan Observatory AZT-33IK telescope, and the 6-m SAO RAS telescope (Bolshoi Teleskop Azimutalnyi, BTA). The spectroscopic redshift measurements have been obtained for 67 galaxy clusters, including 12 galaxy clusters from the second Planck catalogue of Sunyaev–Zeldovich sources.

We present the results of a narrow-band H and [S II] imaging survey of the star-forming regions in Galaxy. Main tasks of this survey are the search and the studies of the new Herbig-Haro objects and collimated outflows, which are the main indicators of active processes of star formation. Besides, the eruptive stars of very rare types: FUors, EXors, UXors will be searched as well. As the main targets of this survey the R associations, young stellar objects associated with compact reflection nebulae as well as the deeply embedded infrared sources in molecular clouds are selected. Observations are performed with 1-m Schmidt telescope at Byurakan Observatory, which is equipped with modern CCD detector. We plan to significantly expand the list of HH objects by using the high quantum efficiency of this system as well as the telescope's high focal ratio (F/2), which allows detecting low surface brightness objects, and its large field of view.

We present the results of methodological works on automated analysis of the large scale distribution of galaxies. Selecting candidates for clusters and groups of galaxies was carried out using two complementary methods of determining the density contrast maps in the narrow layers of the three-dimensional large scale distribution of galaxies: the filtering algorithm with an adaptive core and the Voronoi tesselation. The developed algorithms were tested on 10 data sets of the MICE model catalog; additionally, we determined the statistical parameters of the obtained results (completeness, sample purity, etc.). The constructed density contrast maps were also used to determine voids., Comment: Accepted for publication in Astrophysical Bulletin, 9 pages, 8 figures, 1 table

We present the results of optical spectroscopy for 39 quasar candidates at photometric redshifts zphot ≳ 3 from the catalog by Khorunzhev et al. (2016) (K16). This is a catalog of quasar candidates and known type 1 quasars selected among the X-ray sources of the 3XMM-DR4 catalog of the XMM-Newton serendipitous survey. We have performed spectroscopy for new candidates at the 1.6-m AZT-33IK telescope of the Sayan Solar Observatory and the 6-m BTA telescope of the Special Astrophysical Observatory. Predominantly X-ray bright quasar candidates that could be used to construct the X-ray luminosity function at luminosities LX,2–10 > 1045 erg s−1 have been selected. The purity of the candidates from K16 with a high X-ray flux has turned out to be lower than the purity of the quasi-random sample investigated by us previously. We have estimated the observing efficiency of quasar candidates as a function of their photometric redshift.

We present the first sample of tidal disruption events (TDEs) discovered during the SRG all-sky survey. These 13 events were selected among X-ray transients detected in the 0, Comment: Accepted for publication in MNRAS, 29 pages

We present the results of optical identifications and spectroscopic redshift measurements for galaxy clusters from the second Planck catalogue of Sunyaev-Zeldovich sources. We used the data of observations with the 1.5-m Russian-Turkish telescope (RTT150), the 1.6-m Sayan Observatory AZT-33IK telescope, the 3.5-m Calar Alto telescope, and the 6-m SAO RAS telescope (Bolshoi Teleskop Azimutalnyi, BTA). For the observations we selected Sunyaev-Zeldovich sources unidentified with galaxy clusters with known redshifts. The observations have been carried out for three years, as a result of which we obtained direct images in various filters for a set of galaxy clusters and spectra for the brightest red-sequence galaxies of these clusters. For 38 galaxy clusters we obtained spectroscopic redshift measurements.

The first results of the observations of Mrk1032, conducted with the 6-m telescope of SAO Russia, are given. It is shown, in particular, that a large complex of HII-regions, revealed by the integral-field spectroscopy, is the main source of UV radiation in the galaxy.

Using various techniques of optical observations at the 6-m Russian telescope (emission-line images, long-slit and 3D spectroscopy), we have studied large-scale morphology and kinematics of the ionized gas in the Seyfert galaxy Mrk6. Having a significantly deeper images and spectra than those in previous works, we have not only mapped the ionized gas in the stellar disc but also found a system of faint filaments elongated in the NE direction up to a projected distance of 40 kpc (4.3R$_{25}$). Kinematics as well as an ionization state of the filament gas suggest the scenario that hard radiation of the active nucleus illuminated the matter accreted from outside and orbiting almost orthogonally to the Mrk 6 stellar disc. A possible source of gas accretion is still unknown, a deep image taken with the 1-m Byrakan Schmidt telescope does not show any stellar counterparts at the level of 27-28 mag/arcsec$^2$., Comment: 6 pages, 5 figures. Accepted for publication in MNRAS

In 2013–2015 the Laboratory of spectroscopy and photometry of extragalactic objects (LS-PEO) of the Special Astrophysical Observatory together with Armenian specialists upgraded the 1-m Schmidt telescope of the Byurakan Astrophysical Observatory of the National Academy of Sciences of Armenia. We completely redesigned the control system of the telescope: we replaced the actuating mechanisms, developed telescope control software, and made the guiding system. We reworked and prepared a 4k × 4k Apogee (USA) liquid-cooled CCD with RON ~ 11.1 e−, a pixel size of 0.″868, and field of view of about 1□°, and in October 2015 mounted it in the focus of the telescope. The detector is equipped with a turret bearing 20 intermediate-band filters (FWHM = 250 A) uniformly covering the 4000–9000 A wavelength range, five broadband filters (u, g, r, i, z SDSS), and three narrow-band filters (5000 A, 6560 A and 6760 A, FWHM = 100 A). During the first year of test operation of the 1-m telescope we performed pilot observations within the framework of three programs: search for young stellar objects, AGNevolution, and stellar composition of galaxy disks.We confirmed the possibility of efficiently selecting of young objects using observations performed in narrow-band Hα and [SII] filters and the intermediate-band 7500 A filter. Three-hours long exposures with SDSS g-, r-, and i-band filters allow us to reach the surface brightness level of 28m/□″ when investigating the stellar content of galaxy disks for a sample of nine galaxies. We used observations performed with the 1-m telescope in five broadband (SDSS u, g, r, i, and z) and 15 intermediate-band filters (4000–7500 A) to construct a sample of quasar candidates with 0.5 < z < 5 (330 objects) in about one-sq. degree SA68 field complete down to RAB = 23m. Spectroscopic observations of 29 objects (19.m5 < R < 22m) carried out at the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences confirmed the quasar nature of 28 objects.

We present results of the narrow-band Halpha and [SII] imaging survey of Mon R1 association, performed with the 1 m Schmidt telescope of the Byurakan Observatory. Our observations covered one degree field near the center of the association. As a result of this study twenty new Herbig-Haro knots were discovered, some of which form collimated outflows. Among the most extended ones are HH 1203 and HH 1196, which have a length near one parsec or even more. In the course of search for the probable sources of HH objects several new nebulous stars were found. A list of all nebulous stellar objects in the Mon R1 area under study is presented, with the detailed description of most interesting objects. The near infrared data from the GLIMPSE360 and WISE surveys allowed to find several more objects, related to Mon R1, some of them with optical counterparts, as well as to outline at least three probable H_2 collimated flows from the deeply embedded pre-main-sequence objects. The probable members of Mon R1 were selected by their distances, their bolometric luminosities and extinctions were estimated. Among the outflow sources three embedded objects with luminosities greater than 10 L(sun) were found. The mean distance to Mon R1 complex is estimated as 715 pc., Comment: 12 pages, 16 figures. This is final version of the paper, accepted by MNRAS

The results of the study of the large-scale distribution of galaxies up to z ~0.8 in the field HS 47.5-22 on the basis of photometric data of the 1-meter Schmidt telescope of the BAO NAS Armenia are presented. The full sample contains 28,398 galaxies. Candidates for large-scale structures were determined using two independent methods for reconstructing density contrast maps in 57 narrow slices of the three-dimensional distribution of galaxies: adaptive aperture algorithm with smoothing and 2D Voronoi tessellation. We have identified more than 250 statistically significant overdense structures. The obtained results demonstrate a wide range of overdense structures over the full range of redshifts up to z ~0.8., Comment: Accepted for publication in Astrophysical Bulletin, 16 pages, 14 figures, 2 tabels

We study the reconstruction of overdensity maps of galaxies as function of redshift in the range $0 < \mathrm z < 0.8$ using data from 1-m Schmidt Telescope of Byurakan Astrophysical Observatory (Armenia) in 16 medium band $\sim 250$ A and four broad band (u,g,r,i) filters. The data used in this work homogeneously cover $2.39$ sq. deg with accurate photometric redshiftss, down to $\mathrm R < 23$ mag (AB). We reconstructed the density contrast maps for the whole galaxy sample of the HS 47.5-22 ROSAT field in narrow slices for full range of redshifts. We select groups and clusters of galaxies with adaptive kernel based on density peaks which are larger than two times the mean density. The reconstructed overdensity field of galaxies consists of cluster-like structures outlining void-like regions for full redshift range $0 \leq \mathrm z \leq 0.8$. We detect known galaxy clusters in this field with software specially developed for this project. This gives us a possibility to study how star formation properties and galaxy morphology depend on the environments of the galaxies in this field., 13 pages, 7 figures, 1 Table

Motivated by the discovery of large-scale ionized clouds around AGN host galaxies, and particularly the large fraction of those which are consistent with photoionized gaseous tidal debris, we have searched for [O III] emission over wide fields around a set of Seyfert galaxies previously mapped in H I, many of which show extended gas features. The detection threshold was designed to reach mean emission-line surface brightness 10 times fainter than seen in such AGN-ionized clouds as Hanny's Voorwerp, so that similar structures at larger distances (and ages) could be detected. Of 24 Seyfert galaxies, we find one extended emission feature, a discrete cloud projected 12 kpc from the center of Mkn 1 and spanning a transverse extent of 8 kpc. Optical spectroscopy of the Mkn 1 cloud confirms its redshift association with the Mkn 1- NGC 451 galaxy pair, shows it to closely match the kinematics of nearby H I, and reveals emission-line ratios requiring photoionization by the AGN at roughly the direct observed luminosity of the nucleus. Given the small fraction of H I features with detected [O III] emission, we constrain the typical opening angle of ionization cones in Seyfert galaxies to be of order 20 deg, if active episodes are long compared to the light-travel times involved. An appendix presents a derivation of an analytical expression for the probability of intersection of a cone with randomly oriented arcs, approximating the geometry of H I clouds and tails exposed to ionization cones. For the entire sample, the full opening angle of bicones must be, Submitted to MNRAS

Within the framework of cooperation between Byurakan Astrophysical Observatory and Special Astrophysical Observatory during 2013–2015 y the 1-m Schmidt telescope of the Byurakan Astrophysical was upgraded. We completely redesigned the control system of the telescope: we replaced the actuating mechanisms, developed telescope control software, and made the guiding system. In the Special Astrophysical Observatory the 4k×4k Apogee (USA) liquid-cooled CCD was reworked and prepared. Detector was mounted in the focus of the telescope and provides 1 degree field of view with pixel-size of 0.868, and RON∼11e−. The detector is equipped with a turret with 5 holes for filters. The 20 intermediate-band filters (FWHM= 250A) uniformly covering the 4000–9000 AA wavelength range, five broadband filters (u, g, r, i, z SDSS), and three narrow-band filters. During the first year of test operation of the 1-m telescope we performed pilot observations within the framework of three programs: search for young stellar objects, AGN evolution, and stellar composition of galaxy disks. We confirmed the possibility of efficiently selecting of young objects using observations performed in narrow-band Hα and [S II]filters and the intermediate-band 7500̊Afilter.Three-hours long exposures with SDSS g, r, and i band filters allow us to reach the surface brightness level of 28m from square arcsecond when investigating the stellar content of galaxy disks for a sample of nine galaxies. We used observations performed with the 1-m telescope in five broadband (SDSS u, g, r, i, and z) and 15 intermediate-band filters (4000–7500A) to construct a sample of quasar candidates with 0.5

We describe the design of a low- and medium-resolution spectrograph ( R=300-1300) developed at the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) for the 1.6-m AZT-33IK telescope of Sayan Observatory of the Institute of Solar-Terrestrial Physics of the Siberian Branch of the Russian Academy of Sciences. We report the results of laboratory measurements of the parameters of the instrument and tests performed on the SAO RAS 1-m Zeiss-1000 telescope. We measured the total quantum efficiency of the "spectrograph + telescope + detector" system on AZT-33IK telescope, which at its maximum reaches 56%. Such a hight transparency of the spectrograph allows it to be used with the 1.6-m telescope to determine the types and redshifts of objects with magnitudes m_AB~20-21, that was confirmed by actual observations., 10 pages, 7 figures. Astrophysical Bulletin, 2016, vol. 71, No.4, p. 479

A sample of cataclysmic variables (CVs) detected among the X-ray sources of the 400 square degree (400d) survey performed based on ROSAT pointings is presented. A technique for selecting CVs among the X-ray sources using additional optical and infrared data, based on Sloan Digital Sky Survey andWISE data, is described. We present the optical observations of the selected objects carried out mainly with the Russian–Turkish 1.5-m telescope (RTT-150) and the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences (BTA). Some observations have also been performed with the 1.6-m AZT-33IK telescope of the Institute of Solar–Terrestrial Physics, the Siberian branch of the Russian Academy of Sciences. Eight CVs, four of which were detected in our work, have been selected by now. Based on this sample, we have obtained preliminary constraints on the X-ray luminosity function of CVs in the solar neighborhood in the range of low luminosities, L X ~ 1029–1030 erg s−1 (0.5–2 keV). The logarithmic slope of the CV luminosity function in this luminosity range is shown to become gentler than that at L X > 1031 erg s−1. It follows from our estimates of the CV luminosity function that several thousand CVs will be detected in the SRG all-sky survey at high Galactic latitudes, which will allow much more accurate measurements of their X-ray luminosity function to be obtained.

We study three Arp' systems of peculiar galaxies: Arp 42 (NGC 5829), Arp 82 (NGC 2535/36) and Arp 58 (UGC 4457), using the long-slit spectral observations carried out at the 6m telescope BTA of Special Astrophysical Observatory. Arp 82 and Arp 58 are the M51-type systems. In the third system - Arp 42, there are two extremely luminous kpc-sized clumps observed at the ends of the bifurcated spiral arm, however the source of perturbations remains unknown. From the emission line measurements we analyzed the distribution of gas line-of-sight (LOS) velocity, velocity dispersion and gas-phase metallicity along the slits estimated by different methods. A special attention is paid to the young regions of star formation at the peripheries of the galaxies and in tidal debris, their connection with gas kinematics and abundance. All three systems show the signs of velocity disturbances and the presence of regions of locally enhanced gas velocity dispersion, as well as the regions of diffuse ionized gas. A distribution of oxygen reveals shallow radial abundance gradients, typical for interacting systems. A faint spiral-like branches of tidal bridges which are observed in NGC 2535 and UGC 4457 may represent the remnants of pre-existing "old" mode of spiral waves., Comment: accepted for publication in MNRAS; 15 pages, 14 figures

We present the results of optical identifications and spectroscopic redshifts measurements for galaxy clusters from 2-nd Planck catalogue of Sunyaev-Zeldovich sources (PSZ2), located at high redshifts, $z\approx0.7-0.9$. We used the data of optical observations obtained with Russian-Turkish 1.5-m telescope (RTT150), Sayan observatory 1.6-m telescope, Calar Alto 3.5-m telescope and 6-m SAO RAS telescope (Bolshoi Teleskop Alt-azimutalnyi, BTA). Spectroscopic redshift measurements were obtained for seven galaxy clusters, including one cluster, PSZ2 G126.57+51.61, from the cosmological sample of PSZ2 catalogue. In central regions of two clusters, PSZ2 G069.39+68.05 and PSZ2 G087.39-34.58, the strong gravitationally lensed background galaxies are found, one of them at redshift $z=4.262$. The data presented below roughly double the number of known galaxy clusters in the second Planck catalogue of Sunyaev-Zeldovich sources at high redshifts, $z\approx0.8$., Comment: 12 pages, 9 figures. Accepted for publication in Astronomy Letters

Results of spectroscopic and photometric studies for the locally isolated lenticular galaxy NGC 4124 are presented. A model of the mass distribution consistent with photometric data has been constructed on the basis of a kinematic analysis. In this model, the halo mass within the optical radius is almost half the diskmass. The disk is shown to be in a dynamical state close to amarginally stable one. This rules out dynamical disk heating for the galaxy through a strong external action or a merger with a massive system. However, the presence of a gaseous disk inclined to the main plane of the galaxy in the central kiloparsec region suggests probable cannibalization of a small satellite that also produced a late starburst in the central region. This is confirmed by the younger mean age (∼2 Gyr) of the stellar population in the galaxy’s central region than the disk age (5–7 Gyr).

Spectroscopic observations of 63 Hii regions in six spiral galaxies (NGC 628, NGC 783, NGC 2336, NGC 6217, NGC 7331, and NGC 7678) were carried out with the 6-meter telescope (BTA) of Russian Special Astrophysical Observatory with the Spectral Camera attached to the focal reducer SCORPIO in the multislit mode with a dispersion of 2.1A/pixel and a spectral resolution of 10A. These observations were used to estimate the oxygen and nitrogen abundances and the electron temperatures in Hii regions through the recent variant of the strong line method (NS calibration). The parameters of the radial distribution (the extrapolated central intercept value and the gradient) of the oxyge n and nitrogen abundances in the disks of spiral galaxies NGC 628, NGC 783, NGC 2336, NGC 7331, and NGC 7678 have been determined. The abundances in the NGC 783, NGC 2336, NGC6217, and NGC 7678 are measured for the first time. Galaxies from our sample foll ow well the general trend in the luminosity ‐ central metallicity diagram for spiral and irr egular galaxies.

The methods of panoramic (3D) spectroscopy are used in a detailed study of galaxies with ongoing star formation chosen from among objects in seven selected fields of the Second Byurakan Survey (SBS). This article deals with the irregular galaxy SBS 1202+583, which our classification scheme identifies as being in a continuous phase of starformation. Observations were made with the panoramic spectrographs MPFS at the 6-m telescope of the Special Astrophysical Observatory (SAO) of the Russian Academy of Sciences and VAGR at the 2.6-m telescope of the Byurakan Astrophysical Observatory (BAO) in Armenia. The data are used to construct charts of the radiative fluxes in the continuum and various emission lines. Special attention is devoted to analyzing the emission in the H{\alpha} hydrogen recombination line and in the forbidden low-ionization doublets of nitrogen [NII]{\lambda}{\lambda}6548, 6583 and sulfur [SII]{\lambda}{\lambda} 6716,6731, and the ratios of the intensities of the forbidden lines to H{\alpha}. The observable characteristics (sizes, H{\alpha} fluxes, etc.) of nine HII regions are studied. The estimated current rates of starformation in the individual HII regions based on the H{\alpha} fluxes lie within the range of 0.3-1.2 Msun/year. The dependence of the ratio of the intensities of the emission in these two forbidden doublets on the rate of star formation in the HII regions is found., Comment: 13 pages,8 figures and 3 tables

We present classifications, optical identifications, and radio spectra for eight radio sources from three flux-density-complete samples in the following declination ranges: 4°–6° (B1950), S3.9 > 200 mJy; 10°–12°30′ (J2000), S4.85 > 200 mJy; 74°−75° (J2000), S4.85 > 100 mJy. For all these samples, the right ascensions are 0h–24h and the Galactic latitudes, |b| > 15°. Our optical observations at 4000–7500 ° were made with the 6-m telescope of the Special Astrophysical Observatory; we also observed at 0.97–21.7 GHz with the RATAN-600 radio telescope of the Special Astrophysical Observatory. We classify four of the objects as quasars and four as galaxies. Five of the radio sources have power-law spectra at 0.97–21.7 GHz, while two objects have flat spectra. The quasar J2358+0430 virtually did not vary during 23 years.

We present the results of spectroscopic redshift measurements for the galaxy clusters from the first all-sky Planck catalogue of the Sunyaev-Zeldovich sources, that have been mostly identified by means of the optical observations performed previously by our team (Planck Collaboration, 2015a). The data on 13 galaxy clusters at redshifts from z=~0.2 to z=~0.8, including the improved identification and redshift measurement for the cluster PSZ1 G141.73+14.22 at z=0.828, are provided. The measurements were done using the data from Russian-Turkish 1.5-m telescope (RTT-150), 2.2-m Calar Alto Observatory telescope, and 6-m SAO RAS telescope (Bolshoy Teleskop Azimutalnyi, BTA)., Comment: published in Astronomy Letters

Context. Jets and outflows from young stellar objects (YSOs) can be identified and traced through the distribution and structure of shocked emission-line features. To understand the formation of these regions requires kinematic data at high spectral resolution and with full spatial coverage. Aims. In this work, we investigate the environment of HL/XZ Tau, which contains a compact and very active nest of YSOs. We explore the kinematic properties of the close association of jets in this region and study the interaction of jets with the ambient medium, as well as the outflows with each other. Methods. We present scanning Fabry-Perot interferometry of the HL/XZ Tau region in Ha and [S II] 6716 angstrom emission. We also measure the proper motions of the knots in the outflows, as derived from images obtained in 1997 and 2001, to achieve the full 3D kinematic picture. Results. Radial velocities of the HL Tau jet indicate a fast spine of low excitation surrounded by a slower sheared sheath of higher excitation. Proper motions range from 200-220 km s(-1) in the HL Tau jet and are aligned within 10 degrees of the jet spine. In combination, the proper motions and radial velocities indicate that three outflows in this region may be interacting with each other. Evidence of an outflow associated with LkH alpha 358 is found, and we suggest it is a source of Herbig-Haro (HH) knots that lie to the southeast of HL Tau and HH 265. Conclusions. We conclude that the southern lobe of the XZ Tau wind disrupts the eastern lobe of the collimated outflow from LkHa 358. The jet emerging from HL Tau is deflected by the northern lobe of the wind from XZ Tau. We propose several probable explanations for the unusual structure of the HL Tau jet. It is plausible that the shocks in the jet spine are maintained by the ram pressure of a low-density crosswind from XZ Tau. The crosswind interacts to form a sheath of entrained gas.

A preliminary analysis is given of 2D spectroscopic data on the galaxy SBS 1533+574(AB) obtained using the multipupil spectrographs on the 2.6-m telescope at the BAO (VAGR) and the 6-m telescope at the SAO (MPFS). The two components of the galaxy are star formation regions in different stages. The component SBS 1533+574B is known to be a BCDG. The plots of the intensity distribution of the radiation in the recombination lines of hydrogen and the forbidden lines of gases with a low degree of ionization obtained here make it possible to compare the basic characteristics of the HII-zones and the surrounding shell. The velocity distribution over the field of the galaxy is indicative of a common rotation of the system and of an intrinsic rotation of the components which is more distinct for component B.

We present classifications, optical identifications, and radio spectra for 19 radio sources from three complete samples, with declinations 4°–6° (B1950, S 3.9 GHz > 200 mJy), 10°–12°30′ (J2000, S 4.85 GHz > 200 mJy), and 74°–75° (J2000, S 4.85 GHz > 100 mJy). We also present corresponding information for the radio source J0527+0331. The right ascensions are 0–24h and the Galactic latitudes |b| > 15° for all the samples. Our observations were obtained with the 6 m telescope from the Special Astrophysical Observatory in the range 4000–9000 A or 4000–7500 A and the RATAN-600 radio telescope at frequencies in the range 0.97–21.7 GHz. We obtained flux densities for the radio sources and optical spectra for their optical counterparts. Nine objects were classified as quasars with redshifts from z = 1.029 to 3.212; nine objects are emission-line galaxies with redshifts from 0.172 to 0.546, and one is a galaxy with burstlike star formation at z = 0.156, and one is a BL Lac object with z = 0.509. The spectra of five radio sources were decomposed into extended and compact components. The radio source J0527+0331, identified with a BL Lac object, displays significant variations of time scales from several days to several years. Data on flux variations are presented for 11 radio sources, as well as their spectra at several epochs.

We present optical identifications, classifications, and radio spectra for 19 radio sources from a complete sample in flux density with declinations 10°–12°30′ (J2000) obtained with the 6-m optical telescope (4000–9000 A) and RATAN-600 radio telescope (0.97–21.7 GHz) of the Special Astrophysical Observatory. Twelve objects with redshifts from 0.573 to 2.694 have been classiffied as quasars, and two objects with featureless spectra as BL Lac objects. Four objects are emission-line radio galaxies with redshifts from 0.204 to 0.311 (one also displaying absorption lines), and one object is an absorption-line galaxy with a redshift of 0.214. Radio flux densities have been obtained at six frequencies for all the sources except for two extended objects. The radio spectra of five of the sources can be separated into extended and compact components. Three objects display substantial rapid (on time scales from several days to several weeks) and long-term variability of their flux densities.

We analyzed ionized gas motion and disk orientation parameters for 15 spiral galaxies. Their velocity fields were measured with the H-alpha emission line by using the Fabry-Perot interferometer at the 6m telescope of SAO RAS. Special attention is paid to the problem of estimating the position angle of the major axis (PA_0) and the inclination (i) of a disk, which strongly affect the derived circular rotation velocity. We discuss and compare different methods of obtaining these parameters from kinematic and photometric observations, taking into account the presence of regular velocity (brightness) perturbations caused by spiral density waves. It is shown that the commonly used method of tilted rings may lead to systematic errors in the estimation of orientation parameters (and hence of circular velocity) being applied to galaxies with an ordered spiral structure. Instead we recommend using an assumption of constancy of i and PA_0 along a radius, to estimate these parameters. For each galaxy of our sample we present monochromatic H-alpha- and continuum maps, velocity fields of ionized gas, and the mean rotation curves in the frame of a model of pure circular gas motion. Significant deviations from circular motion with amplitudes of several tens of km/s (or higher) are found in almost all galaxies. The character and possible nature of the non-circular motion are briefly discussed., Comment: Accepted in A&A, fig. 2-19 are low-resolution JPGs, for high-resolution PS see http://www.sao.ru/hq/moisav/moisav/fintext.ps.gz

We performed spectroscopic observations of 22 radio sources from the Zelenchuk survey (Sternberg Astronomical Institute) using the 6-m and 1-m Special Astrophysical Observatory telescopes. For 18 objects, we determined the redshifts. Ten, seven, and one of these objects were identified with quasars, elliptical galaxies, and a Seyfert galaxy, respectively. Four radio sources have a continuum spectrum, and three of them are BL Lac objects. We failed to classify one object.

We present the classification of optical identifications and radio spectra of six radio sources from a complete (in flux density) sample in the declination range 10° to 12°30′ (J2000.0). The observations were carried out with the 6-m Special Astrophysical Observatory telescope (Russia) in the wavelength range 3600–10000 A, the 2.1-m GHAO telescope (Mexico) in the range 4200–9000 A, and the RATAN-600 radio telescope in the frequency range 0.97–21.7 GHz. Three of the six objects under study are classified as quasars, one is a BL Lac object, one is an absorption-line radio galaxy, and one is an emission-line radio galaxy. Five objects have flat radio spectra, and one object has a power-law radio spectrum. All of the radio sources identified as quasars or BL Lac objects show variable radio flux densities. The spectra of three objects were separated into extended and compact components.

Optical identifications and an analysis of the radio spectra of eight radio sources from a flux-density-complete sample at declinations 4°–6° (B 1950) are presented. The observations were carried out at 4000–9000 A on the 6-m telescope of the Special Astrophysical Observatory and at 0.97–21.7 GHz on the RATAN-600 telescope. Five of the eight sources are quasars and three are emission-line radio galaxies.

The results of spectroscopic observations of the host galaxies of objects in the RC catalog (the “Big Trio” program) obtained using the new SCORPIO spectrograph of the Special Astrophysical Observatory are presented. The spectroscopic redshifts of the objects are compared with their photometric color redshifts, and the errors in the latter are estimated. Based on BV RI observations obtained on the 6-m telescope of the SAO, the errors for the population of powerful radio galaxies are close to those found previously for radio quiet galaxies (about 10–20%). The detection of Ly α in the B filter in RC 1626+0448 is confirmed. This object is the second spectrally studied FR II radio source from the RC catalog to have a redshift z>2.5. Star formation in its host galaxy began at a redshift z>3.3. This first use of the new SCORPIO spectrograph demonstrates its promise for studies of very distant steep-spectrum radio galaxies brighter than 23m–24m in V.

Observations of the extraordinarily bright optical afterglow (OA) of GRB 991208 started 2.1 d after the event. The flux decay constant of the OA in the R-band is -2.30 +/- 0.07 up to 5 d, which is very likely due to the jet effect, and after that it is followed by a much steeper decay with constant -3.2 +/- 0.2, the fastest one ever seen in a GRB OA. A negative detection in several all-sky films taken simultaneously to the event implies either a previous additional break prior to 2 d after the occurrence of the GRB (as expected from the jet effect). The existence of a second break might indicate a steepening in the electron spectrum or the superposition of two events. Once the afterglow emission vanished, contribution of a bright underlying SN is found, but the light curve is not sufficiently well sampled to rule out a dust echo explanation. Our determination of z = 0.706 indicates that GRB 991208 is at 3.7 Gpc, implying an isotropic energy release of 1.15 x 10E53 erg which may be relaxed by beaming by a factor > 100. Precise astrometry indicates that the GRB coincides within 0.2" with the host galaxy, thus given support to a massive star origin. The absolute magnitude is M_B = -18.2, well below the knee of the galaxy luminosity function and we derive a star-forming rate of 11.5 +/- 7.1 Mo/yr. The quasi-simultaneous broad-band photometric spectral energy distribution of the afterglow is determined 3.5 day after the burst (Dec 12.0) implying a cooling frequency below the optical band, i.e. supporting a jet model with p = -2.30 as the index of the power-law electron distribution., Comment: Accepted for publication in Astronomy and Astrophysics, 9 pages, 6 figures (Fig. 3 and Fig. 4 have been updated)

The results of observations of 49 objects from the second Byurakan spectroscopic sky survey are given; they complete the recent spectroscopy of galactic samples in the fields centered on the coordinates α = 09h47m, δ = +51° and α = 09h50m, δ = +55°. The spectra were obtained on the 2.6-m telescope of the Byurakan Astrophysical Observatory, National Academy of Sciences of the Republic of Armenia, and the 6-m telescope of the Special Astrophysical Observatory, Russian Academy of Sciences, during 1998-2000. Redshifts and absolute stellar magnitudes were determined for all the galaxies.

Due to the invention of new methods for searching high redshift star forming galaxies they are no longer a curiosity. High redshift star forming galaxies can be effectively discriminated from much more abundant foreground galaxies by their spectral properties: a prominent break at Lyman limit, an intrinsically flat spectrum at wavelength long-ward of Lyman limit and in the very early phase of evolution a strong Ly α. emission line with high equivalent width. Here we discuss the galaxies with the highest redshifts we know today and their properties and give an overview over the survey of high redshift star forming galaxies we developed on 2.6-m Telescope Byurakan Observatory and on 6-m Telescope of SAO RAS.

We report detection of giant cyclonic vortices in the gaseous disc of the spiral galaxy NGC 3631 in the reference frame rotating with the spiral pattern. A presence of such structures was predicted by the authors for galaxies, where the radial gradient of the perturbed velocity exceeds that of the rotational velocity. This situation really takes place in NGC 3631., 13 pages, 4 EPS and 3 PS figures

General ideas, as well as experimental and theoretical efforts concerning the prediction and discovery of new structures in the disks of spiral galaxies – giant anticyclones - are reviewed. A crucial point is the development of a new method to restore the full vector velocity field of the galactic gas from the line-of-sight velocity field. This method can be used to get self-consistent solutions for the following problems: 1) determination of non-circular velocities associated with spiral-vortex structure; 2) determination of fundamental parameters of this structure: pattern speed, corotation radius, location of giant anticyclones; 3) refinement of galactic rotation curves taking into account regular non-circular motion in the spiral density wave, which makes it possible to build more accurate models of the mass distribution in the galaxy; 4) refinement of parameters of the rotating gaseous disk: inclination angle, center of rotation and position angle of the major dynamical axis, systematic velocity. The method is demonstrated using the restoration of the velocity field of the galaxy NGC 157 as an example. Results for this and some other spiral galaxies suggest that giant anticyclones are a universal property of galaxies with grand design structure.

Integral Field Spectrograph observations of southeast (SE) gas outflow in the center (11×13 arcsec) of NGC 4258 with spatial sampling 0.6 and 1.2 arcsec were made with the 6-m Telescope. Reconstructed spatial and kinematic structure of the SE outflow from 20-30 pc to 200-220 pc are presented.

We present the results of spectroscopy of 39 H II regions in the spiral galaxy NGC 6946. The spectral observations were carried out at the 6-m BTA telescope of the SAO RAS with the SCORPIO focal reducer in the multi-slit mode with the dispersion of 2.1A/px and spectral resolution of 10A. The absorption estimates for 39 H II regions were obtained. Using the "strong line" method (NS-calibration) we determined the electron temperature, and the abundances of oxygen and nitrogen for 30 H II regions. The radial gradients of O/H and N/H were constructed., Comment: 11 pages, 9 figures, 5 tables. Published in Astrophysical Bulletin

We present the observations of the BCDG IZW18 performed with a Fabry-Perot interferometer at the CFH 3.6 m telescope and with a multi-pupil spectrograph at the SAO (Russia) 6 m telescope. The morphological structure of the galaxy in emission lines and in continuum, the velocity field of the ionized gas, and [OIII]/H β ratio distribution along the NW component have been investigated. Besides the NW and SE HII components, we find a population of small HII regions. Continuum maps show that the peaks of the stellar light distribution are displaced with respect to the emission lines maxima. the velocity field shows peculiar motions superposed on an approximately regular background implying solid body rotation. Emission line profiles exhibit an asymmetric structure, except for the NW compact component. The [OIII]/H β ratio decreases from the center of the NW component to its edge with the gradient of 1.86 kpc−1.

The nuclear region of the NGC 4258 was observed at the 6m Telescope using an integral field spectrograph. Monochromatic maps in Ha and [NII] 6548/6583 Ålines were constructed from the data. Based on monochromatic maps and a velocity field with spatial sampling 0.6 arcsec, and the data published by Courtes et al., (1993) and Cecil et al., (1993) data, we tried to reconstruct the structure of the outflow.