Byurakan Survey Research Articles

Markarian Galaxies. I. The Optical Database and Atlas

A database for the entire Markarian catalog is presented that combines extensive new measurements of their optical parameters with a literature and database search. The measurements were made using images extracted from the STScI Digitized Sky Survey (DSS) of Fpg(red) and Jpg(blue) band photographic sky survey plates obtained by the Palomar and UK Schmidt telescopes. We provide accurate coordinates, morphological type, spectral and activity classes, red and blue apparent magnitudes, apparent diameters, axial ratios, and position angles, as well as number counts of neighboring objects in a circle of radius 50 kpc. Special attention was paid to the individual descriptions of the galaxies in the original Markarian lists, which clarified many cases of misidentifications of the objects, particularly among interacting systems, larger galaxies with knots of star formation, possible stars, and cases of stars projected on galaxies. The total number of individual Markarian objects in the database is now 1544. We also include redshifts that are now available for 1524 objects with UV-excess radiation, as well as galactic color excess E(B - V) values and their 2MASS or DENIS infrared magnitudes. The database also includes extensive notes that summarize information about the membership of Markarian galaxies in different systems of galaxies and about new and revised activity classes and redshifts. An atlas of several interesting subclasses of Markarian galaxies is also presented.

The digitized first Byurakan survey – DFBS

Context. The First Byurakan Survey (FBS), also known as the Markarian Survey, is the largest low resolution spectroscopic survey of the sky and led to the discovery of 1500 UV-excess (UVX) galaxies and starburst galaxies. The FBS plates have also been used to search for UVX stellar objects, late-type stars, and for the identification of unusual infrared sources.Aims. The Digitized First Byurakan Survey (DFBS) provides the astronomical community with a digitized version of the FBS images and with the extracted spectra for the objects present in the plates.Methods. Nearly 2000 plates have been scanned and stored and programs were developed to compute the astrometric solution, extract the spectra, and apply wavelength and photometric calibration for the objects present in the plates.Results. The DFBS database and catalog of objects has been assembled. The DFBS database contains data for 20 000 000 objects present in the survey and provides tools for accessing the DFBS.Conclusions. New scientific projects as well as existing surveys will benefit by the digitized images and the ready-to-use extracted spectra which will allow an efficient computer-based analysis of the dataset.

Physical Parameters and Classification of Eight Galactic Nuclei from the Second Byurakan Survey

ABSTRACTAccurate estimates of spectral parameters are essential to investigate the physical conditions in active galactic nuclei (AGNs). In particular, intrinsic reddening can be estimated from the Hα/Hβ ratio of the narrow‐line components. The mass of the central black hole can be obtained from the stellar velocity dispersion in the bulge, which can be estimated from the [O iii] λ5007 line width or from the relation between the AGN luminosity and the width of the broad Hβ component. Two different luminosity values are important: one is derived from the monochromatic flux at 5100 Å, and the other is the integrated luminosity for the broad component of Hβ. The spectral parameters are also a fundamental key to obtaining a reliable classification. Spectroscopic observations with a resolution of 4.5 Å were performed for a sample of eight galactic nuclei extracted from the Second Byurakan Survey, in addition to one galaxy companion of SBS 1204+505B. The equivalent width and FWHM of the emission lines were measured, and useful line ratios and diagnostic diagrams were used for object classification and reddening estimates. Intrinsic reddening quantities were calculated for all non–quasi‐stellar objects (QSOs) (i.e., seven objects). In particular, these include the amount of reddening, B - V color excess, extinction coefficient, and optical depth in the V band, at the Hα and Hβ wavelengths, and at 5100 Å. The size of the broad‐line region was also estimated for seven objects, as were the central black hole masses. Three mass estimates were usually performed for each object and were compared. A peculiar line, probably He i λ5048, is detected in the QSO SBS 1626+554. Evidence for a stratified narrow‐line region is found for the two narrow‐line Seyfert 1 galaxies included in the sample. A revised classification is proposed for two objects, and the galaxy companion of SBS 1204+505B is reported as being a nuclear starburst galaxy.

The properties of carbon stars found in the Byurakan and the Hamburg/ESO surveys

Aims. We analyse two samples of high latitude carbon stars found in two objective-prism surveys: the First Byurakan survey (FBS) and the Hamburg/ESO survey (HES). We determine the composition of these samples in cool AGB stars, warmer giants and dwarf carbon stars. Methods. We list 44 new carbon stars found in the FBS and use near-infrared photometric catalogues (DENIS, 2MASS) to investigate the observational and statistical properties of the surveys. The SuperCOSMOS and USNO-B1.0 catalogues are used to study proper motions and to identify dwarfs. Results. The colour–magnitude and colour–colour diagrams, either with visual magnitudes or with infrared data, show that the HES selects faint and relatively warm carbon stars, whereas FBS is less deep, but gives cooler objects. By comparing DENIS and 2MASS photometry, we find that HES objects with $J-K$ ≤ 1 are mostly non-variable giants while clear variability is often seen for $J-K$ ≥ 1, indicating AGB stars. By using SuperCOSMOS proper motions, 9 HES objects are found to have a proper motion μ greater than 30 mas yr -1 (3 σ detection). Five of these objects are detected at the ≥ 5 σ level. These 9 HES objects are dwarf carbon stars, including two that could belong to the halo population. The 9 carbon dwarfs are remarkably bright and deserve further study.

Galaxy Evolution Traced by Multiple Galaxies from the BIG Sample

AbstractOptical identifications of all IRAS PSC sources at high galactic latitudes by means of the First Byurakan Survey (FBS) in the area with +61° < δ < +90° at galactic latitudes |b|>15° have been carried out with a total surface of 1487 deg2. 1577 sources have been optically identified, 1178 sources corresponding to galaxies. The BIG sample (Byurakan-IRAS Galaxies) was constructed of 1178 newly identified galaxies and 789 other IRAS galaxies in the same area, known before, altogether 1967 galaxies. Studies of the BIG objects include: spectroscopic follow-up for the brighter (<18m) objects; discovery and study of new AGN; discovery and study of new ULIRGs; deep imagery of the most interesting objects and the “empty fields”; 2D spectroscopy of interacting/merging systems; search for obscured IRAS galaxies (with the Spitzer Space Telescope), etc. The BIG objects are a rich source for new AGN, high-luminosity IR galaxies (hence, starburst activity), and interacting/merging systems. All these phenomena are crucial for understanding the galaxy evolution and their interrelation, as well as the triggering of the powerful IR radiation. In frame of the redshift survey of these galaxies, spectroscopic observations have been carried out for the BIG objects (including the pairs and multiples) by means of the Byurakan Astrophysical Observatory (BAO, Armenia) 2.6m, Special Astrophysical Observatory (SAO, Russia) 6m, and Observatoire de Haute Provence (OHP, France) 1.93m telescopes. It is shown that, without an exception, all double/multiple BIG systems are physical pairs or groups, and they are mostly interacting and/or merging systems. From the high IR luminosities derived from the observations, one can conclude that perhaps the ULIRG/HLIRG phenomenon is connected with galaxy interactions/merging. We find an evolution in luminosity function of these objects with respect to their redshift distribution.Existence of AGN among the multiple BIG objects provides a chance for study of the galaxy evolution in sense of interrelationship between the three phenomena: starburst, interactions/merging, and nuclear activity. We have shown (Mickaelian et al. 2001) that the maximum IR luminosity of a single spiral galaxy may not be larger than 1012 Solar luminosities. Hence, all high-L IRAS galaxies are interacting pairs/multiples or mergers. But what is the relation of the active nucleus to the starburst (i.e. IR) activity?

Science projects with the Armenian Virtual Observatory (ArVO)

The main goal of the Armenian Virtual Observatory is to develop efficient methods for science projects based on the digitized famous Markarian survey (Digitized First Byurakan Survey, DFBS) and other large astronomical databases, both Armenian and international. Two groups of projects are especially productive: search for new interesting objects of definite types by low-dispersion template spectra, and optical identifications of new gamma, X-ray, IR and radio sources. The first one is based on modeling of spectra for a number of types of objects: QSOs, Seyfert galaxies, white dwarfs, subdwarfs, cataclysmic variables, planetary nebulae, late-type stars (K-M, S, carbon), etc. Each kind of object appears in the DFBS with its typical SED and spectral lines (for objects having broad lines only, like white dwarfs and subdwarfs, quasars and Seyferts, etc.), however affected also by its brightness, so that each template works for definite range of magnitudes. The search criteria define how many objects will be found for further study, and may restrict these numbers leaving with the best candidates. Optical identifications have been proven to be rather efficient for IR sources from IRAS-psc and -fsc. Tests have been carried out for X-ray and radio sources as well. Special emphasis is put on search for bright QSOs missed by the Sloan Digital Sky Survey (SDSS), rather important for making up their complete sample, studies of the properties of the Local Universe, a comparison of their X-ray, IR, and radio properties and making up their multiwavelength SEDs, as well as for a refinement of the AGN classification. A project for search for new bright QSOs using the DFBS has been started in the region with δ>0° and |b|>20°. The Byurakan 2.6m telescope is being used for the spectral identification of the candidates. The first test resulted in 145 objects found, 81 being known QSOs/Sys, and 64 new candidates (including 23 NVSS and FIRST radio sources).

Revised and updated catalogue of Byurakan-IRAS stars

Context.Five lists of late-type stars were published in Astrophysics in 1997–2001, found in the First Byurakan Survey low-dispersion spectroscopic plates as optical identifications of unidentified IRAS sources. These identifications were carried out in the region with and with a surface of 1504 deg2. As a result, the catalogue of the Byurakan-IRAS Stars (BIS) was compiled. Its preliminary version has been available at the CDS since 2003.

Erratum: On multi-nuclei features of some Markarian galaxies

Erratum: On multi-nuclei features of some Markarian galaxies

On multi-nuclei features of some Markarian galaxies

We present a spectroscopic investigation of an unusual cluster of galaxies that contains galaxies Mrk 261 and 262 which have ultraviolet excess at the same redshift of about 0.03. We also study Mrk 266, which has a peculiar optical morphology and a binary nucleus. The nuclear components in both of these samples show quite similar emission lines in their spectra to Seyfert galaxy activity characteristics. The kinematics and physical properties of the gas in Mrk 266 allow a reliable mass estimate to be made assuming that the characteristic broad emission lines arise from the photoionization of the virialized clouds by the central ionizing nucleus. However, the nuclei masses would be overestimated if the radiation pressure and/or magnetic fields contribute significantly to the dynamics, or if the outflows or winds could cause the observed linewidths to exceed those induced by the nucleus potential alone.

Radio Identifications of Markarian Galaxies and the Correlation between Radio and Far-Infrared Properties

By checking DSS optical images and NVSS radio images, 782 Markarian galaxies were identified to be NVSS radio sources. A comparison of the radio luminosity at 1.4 GHz and the far-infrared (FIR) luminosity for 468 ``normal galaxies shows a tight correlation. Most of the Seyfert galaxies and quasars follow the radio-FIR relation deduced from the ``normal galaxy sample, but with a somewhat larger scatter. A total 167 Markarian galaxies, comprising 100 ``normal galaxies, 66 Seyfert galaxies and one quasar, have either excess radio emission or much lower FIR spectral index α (25μm, 60μm). These galaxies may be classified as ``AGN-powered. For ``normal galaxies, the average q value (defined as the log ratio between FIR and radio luminosities) is 2.3. There seems a trend for q to slightly decrease with increasing radio luminosity. This may imply that the ongoing active star formation in galaxies with higher radio luminosities is more efficient in heating the cosmic-ray electrons.

Active and Star-forming Galaxies and Their Supernovae

To investigate the extent to which nuclear starbursts or other nuclear activity may be connected with enhanced star formation activity in the host galaxy, we perform a statistical investigation of supernovae (SNe) discovered in host galaxies from four samples: the Markarian galaxies sample, the Second Byurakan Survey (SBS) sample, the north Galactic pole (NGP) sample of active or star-forming galaxies, and the NGP sample of normal galaxies. Forty-seven SNe in 41 Mrk galaxies, 10 SNe in six SBS galaxies, 29 SNe in 26 NGP active or star-forming galaxies, and 29 SNe in 26 NGP normal galaxies have been studied. We find that the rate of SNe, particularly core-collapse (Types Ib/c and II) SNe, is higher in active or star-forming galaxies in comparison with normal galaxies. Active or star-forming host galaxies of SNe are generally of later morphological type and have lower luminosity and smaller linear size than normal host galaxies of SNe. The radial distribution of SNe in active and star-forming galaxies shows a higher concentration toward the center of the active host galaxy than is the case for normal host galaxies, and this effect is more pronounced for core-collapse SNe. Ib/c-type SNe have been discovered only in active and star-forming galaxies of our samples. About 78% of these SNe are associated with H II regions or are located very close to the nuclear regions of these active galaxies, which are in turn hosting AGNs or starburst nuclei. Besides these new results, our study also supports the conclusions of several other earlier papers. We find that Type Ia SNe occur in all galaxy types, whereas core-collapse SNe of Types Ib/c and II are found only in spiral and irregular galaxies. The radial distribution of Type Ib SNe in their host galaxies is more centrally concentrated than that of Type II and Ia SNe. The radial distances of Types Ib/c and II SNe, from the nuclei of their host galaxies, is larger for barred spiral hosts. Core-collapse SNe are concentrated in spiral arms and are often close to or in the H II regions, whereas Type Ia SNe show only a loose association with spiral arms and no clear association with H II regions.

The Digitized First Byurakan Survey - DFBS

The First Byurakan Survey (FBS) is the largest spectral survey in the Northern sky. One can select objects by color, broad absorption and emission lines, and SED; classify and investigate them. The digitization of the FBS is aimed at making a DFBS database available for the astronomical community. Besides scanning, we are creating plate solutions, extraction software, wavelength and flux calibration, templates for different types of objects, numerical classification, a catalog of objects, a database of spectra, a user interface and a DFBS web page. New research projects based on the DFBS are possible, including a search for new QSOs and other AGN, a continuation of the second part of FBS, and identifications of radio, IR and X-ray sources. The DFBS database will be available at the end of 2004.

DSS1/DSS2 astrometry for 1101 First Byurakan Survey blue stellar objects: Accurate positions and other results

Accurate measurements of the positions of 1101 First Byurakan Survey (FBS) blue stellar objects (the Second part of the FBS) have been carried out on the DSS1 and DSS2 (red and blue images). To establish the accuracy of the DSS1 and DSS2, measurements have been made for 153 AGN for which absolute VLBI coordinates have been published. The rms errors are: 0.45 �� for DSS1, 0.33 �� for DSS2 red, and 0.59 �� for DSS2 blue in each coordinate, the corresponding total positional errors being 0.64 �� ,0 .46 �� ,a nd 0.83 �� , respectively. The highest accuracy (0.42 �� ) is obtained by weighted averaging of the DSS1 and DSS2 red positions. It is shown that by using all three DSS images accidental errors can be significantly reduced. The comparison of DSS2 and DSS1 images made it possible to reveal positional differences and proper motions for 78 objects (for 62 of these for the first time), including new high-probability candidate white dwarfs, and to find objects showing strong variability, i.e. high-probability candidate cataclysmic variables.

Properties of Galaxies in the Second Byurakan Survey. II. Characteristic Features of a Separate Sample of Galaxies

Some features of a sample of galaxies from the Second Byurakan Survey are discussed. Most of them are small galaxies with star formation. It is shown that different types of galaxies are in the Survey, with high, medium, and low levels of excitation and continua ranging from blue to relatively red. Many of the galaxies have absorption lines in their spectra; their continua are formed by stars in later spectral classes.

Spectroscopy of Galaxies in Selected Fields of the Second Byurakan Survey

Spectroscopic data are presented for 35 galaxies from selected fields of the Second Byurakan Survey (SBS). The observations were made on the 2.6 m telescope at the BAO using the SCORPIO spectral camera. A majority of the objects were observed for the purpose of improving the classification of types in accordance with an adapted scheme presented in this paper.

On the radio continuum, molecular gas content and optical emission of Markarian galaxies with Seyfert nuclei

In this paper we interpret C and X-band radio continuum observations of a sample of Markarian galaxies. The results are briefly discussed. Seyfert 2 galaxies show sistematically higher HI mass-to-blue magnitude than Seyfert 1 galaxies, as well as higher radio to far-infrared luminosities. The observational properties are interpreted in terms of simple non-thermal and dust emission. We obtained radio brightness temperatures, equipartion magnetic fields and total magnetic densities for the disks. Upper limits for thermal densities are derived from simple free-free emission. Star formation rates and mean supernova rates are estimated for individual Markarian galaxies. The SFR values of the most luminous Markarian galaxies are considerably higher than those found in compact blue dwarf galaxies and also in gas-rich, early-type spirals.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Properties of Galaxies in the Second Byurakan Survey. I. Diagnostic Diagrams

The relative intensities and equivalent widths of emission lines are determined for a number of galaxies in the Second Byurakan Survey for which basic data have been published previously. Diagnostic diagrams are constructed. The properties of this subsample of the galaxies in the survey are discussed.

The PDS versus Markarian starburst galaxies: comparing strong and weakIRASemitter at 12 and 25 μm in the nearby Universe

The characteristics of the starburst galaxies from the Pico dos Dias survey (PDS) are compared with those of the nearby UV-bright Markarian starburst galaxies, having the same limit in redshift (vh < 7500 km s 1 ) and absolute B magnitude (MB < 18). An important difference is found: the Markarian galaxies are generally undetected at 12µm and 25µm in IRAS. This is consistent with the UV excess shown by these galaxies and suggests that the youngest star forming regions dominating these galaxies are relatively free of dust. The FIR selection criteria for the PDS is shown to introduce a strong bias towards massive (luminous) and large size late-type spiral galaxies. This is contrary to the Markarian galaxies, which are found to be remarkably rich in smaller size early-type galaxies. These results suggest that only late-type spirals with a large and massive disk are strong emitter at 12µm and 25µm in IRAS in the nearby universe. The Markarian and PDS starburst galaxies are shown to share the same environment. This rules out an explanation of the differences observed in terms of external parameters. These differences may be explained by assuming two different levels of evolution, the Markarian being less evolved than the PDS galaxies. This interpretation is fully consistent with the disk formation hypothesis proposed in Coziol et al. (2000) to explain the special properties of the Markarian SBNG.

MULTIWAVELENGTH SEARCH FOR AND STUDIES OF ACTIVE GALAXIES: AN INTERNATIONAL COLLABORATION BETWEEN THE BYURAKAN OBSERVATORY AND OBSERVATOIRE DE HAUTE-PROVENCE

An international collaboration on the multiwavelength search for and studies of active galaxies between the Byurakan Astrophysical Observatory (Armenia) and Observatoire de Haute-Provence (France) has been ongoing since 1997. The blue stellar objects of the first Byurakan survey have been studied in order to reveal and build a sample of new bright quasistellar objects and to determine their surface density. On the basis of optical identifications of 1577 IRAS point sources, a new (Byurakan-IRAS galaxy) sample of IRAS galaxies has been constructed and studied. 90 bright Seyfert 1 galaxies have been observed with a high resolution to make a fine analysis of their emission line profiles and to study their emission line regions. A new programme of investigation of Roentgen Satellite (ROSAT) sources identified by the Hamburg quasar survey has been conducted to search for new narrow-line Seyfert 1 galaxies. Databases and observations in the optical, infrared, radio and X-ray ranges are being used.

A Multiwavelength Study of Narrow‐Line Seyfert 1 Galaxies from the Second Byurakan Survey

In this work we present a multiwavelength study of narrow-line Seyfert 1 galaxies (NLS1s) discovered in the Second Byurakan Survey (SBS). The sample consists of 26 objects, which have MB ≥ -23.0, or -19.9 > MB > -23.0, 0.0243 1). The traditional linear correlation LX and Lop, which seems to hold for active galactic nuclei in general, is found for SBS NLS1s. An anticorrelation between the FWHM of Hβ and the ratio of Fe II λ4570/Hβ is also observed. A weak correlation is found between αox slope and Lop. One of our main findings is that almost all SBS NLS1s may not have an FIR bump. Their spectral energy distribution suggests that they may also possess a big blue bump. The absence of an IR bump in most SBS NLS1s and the weakness of X-ray radiation in some of them may argue against the presence of a broad-line region. The surface density of SBS NLS1s is less than 0.015 deg-2 (B < 17.5,z < 0.16).