Study of Starburst/Activity/Interaction Phenomena based on the Multiple Byurakan-IRAS Galaxies

The Byurakan-IRAS Galaxy (BIG) sample is the result of optical identifications of IRAS PSC sources at high-galactic latitudes using the First Byurakan Survey (FBS) low-dispersion spectra. Among the 1178 objects most are spiral galaxies and many have been proved to be AGN and starburst by spectroscopic observations, as well as there is a number of ULIRGs among these objects. BIG objects contain galaxy pairs, multiples, and small groups that are subject for study on the matter of the real IR-emitter in these systems. Given that these objects are powerful IR sources, they are considered as young systems indicating high rate of evolution and starburst activity exceeding 100 Mo/yr. Spectroscopic observations show that all these systems are physical ones and we were able to measure the mutual distances and sizes for all components. Cross-correlations with the recent more accurate IR catalogues, such as 2MASS and WISE, as well as radio ones (NVSS, FIRST), provided accurate coordinates of the IR source and possibility to find the individual galaxy responsible for the IR. However, in almost half of the cases, IR position indicates the intermediate region between the components, which means that it comes from the system as a whole. Some more MW data have been matched to IR and radio to have an overall understanding on these systems. Given that these systems are mostly interacting/merging ones often containing AGN and most of them may be considered as powerful starbursts, it is possible to study starburst/activity/interaction phenomena and their interrelationship.

Study of the Byurakan-IRAS galaxy sample

The Byurakan-IRAS Galaxy (BIG) sample (Mickaelian 1995) is the result of optical identifications of IRAS PSC sources at high-galactic latitudes using the First Byurakan Survey (FBS) low-dispersion spectra (Markarian et al. 1989). Among the 1577 objects 1178 galaxies have been identified. Most are dusty spiral galaxies and there are a number of ULIRGs among these objects. Our spectroscopic observations carried out with three telescopes (Byurakan Astrophysical Observatory 2.6m, Russian Special Astrophysical Observatory 6m and Observatoire de Haute Provence 1.93m) (Mickaelian & Sargsyan 2010) for 172 galaxies, as well as the SDSS DR8 spectra for 83 galaxies make up the list of 255 spectroscopically studied BIG objects. The classification to activity types for narrow-line emission galaxies has been carried out using the diagnostic diagrams by Veilleux & Osterbrock (1987). All possible physical characteristics have been measured and/or calculated, including radial velocities and distances, angular and physical sizes, absolute magnitudes and luminosities (both optical and IR). IR luminosities and star-formation rates have been calculated from the IR fluxes (Duc et al. 1997).Among the 172 observed galaxies, 102 starburst (HII) ones, 29 AGN (Sy or LINER), and 19 galaxies with composite spectrum have been revealed; spectra of 12 galaxies show emission features but without a possibility for more accurate classification, 9 galaxies are presented as galaxies where the star formation rate does not exceed normal one, and 1 galaxy is an absorption galaxy. Among the 83 objects having SDSS spectra, there are 55 HIIs, 8 Seyferts, 2 LINERs, 4 other AGN (without accurate classification), 6 composite spectrum objects and 8 other emission-line galaxies. In our spectroscopic sample we have 43 (17%) AGN, 25 (10%) composite spectrum objects, 157 (62%) starbursts, 29 emission-line galaxies without a definite type, and 1 absorption-line galaxy. There are 3 Ultra-Luminous InfraRed Galaxies (ULIRG).Various multiwavelength (MW) data have been retrieved for the full sample of 1178 objects from recent catalogs from X-ray to radio (ROSAT, GALEX, APM, MAPS, USNO, GSC, SDSS, 2MASS, WISE, IRAS, AKARI, NVSS, FIRST, etc.) to make a complete study of these galaxies possible. MW SEDs have been built, which have been matched to their optical classifications. Star-formation rates have been calculated to compare to their other physical characteristics, such as morphology, activity types, UV, optical, IR and radio luminosities, etc.

Byurakan–IRAS Galaxy Pairs as Indicators of Starburst and Galaxy Evolution

The Byurakan–IRAS galaxies (BIG objects; Mickaelian 1995) are the result of a project of optical identifications of IRAS Point Source Catalog (PSC; IRAS 1988) in a 1500 square degree high-galactic latitude (|b|>15°) area based on the Digitized Sky Survey (DSS) images and the Digitized First Byurakan Survey (DFBS, or digitized Markarian survey) low-dispersion spectra. As a result, 1278 galaxies have been identified (as well as galactic objects, Byurakan–IRAS Stars [BIS]), including 42 PSC sources identified with 103 galaxies that make up 30 physical pairs and 12 multiples.

The Byurakan-IRAS Galaxy (BIG) Sample: The Redshift Survey

The Byurakan-IRAS Galaxy (BIG) sample (1967 galaxies) is based on optical identifications of IRAS PSC sources at δ>+61° and |b| >15° (FBS area). A redshift survey for brighter objects (B<18m) is being carried out with the Byurakan Observatory 2.6m, Special Observatory 6m, and Observatoire de Haute-Provence 1.93m telescopes. 213 objects have been observed, and redshifts in the range 0.008-0.173 have been measured. For this subsample, 15% of the objects are AGNs, and 15% are LIGs and ULIGs.

Investigation of the Local Universe by Means of IRAS Galaxies

The Byurakan-IRAS galaxy (BIG) sample is based on optical identifications of IRAS PSC sources (Beichman, C. A. et al., eds. 1988, Infrared Astronomical Satellite (IRAS) Catalogs and Atlases: The Point Source Catalog, NASA RP–1190, Washington, DC). It makes use of the IR colours, DSS images, and the First Byurakan Spectral Survey (Markarian, B. E. et al. 1989, Commun. Special Astrophys. Obs., 62, 5).All IRAS sources in the region +61° < δ < 90° at high galactic latitudes (|b| >15°) in an area of 1487 deg2 have been revealed up to the limit of the IRAS survey. The BIG sample (Mickaelian, A. M. 2000, Afz, 43, 425 and references therein) consists of 1500 galaxies, including 870 that were previously known. A redshift survey for brighter objects is being carried out with the SAO (Russia) 6 m, Byurakan Observatory 2.6 m, and Observatoire de Haute Provence 1.93 m telescopes. Redshifts in the range of 0.009–0.173 have been measured. For fainter objects, including 30 empty fields corresponding to sources with IR colors typical of galaxies, deep imaging is being carried out to reveal faint objects and study their morphologies. These objects are candidate ULIRGs. Many are multiple galaxies and small groups. About half of the galaxies are radio sources, and a number are also X-ray sources. The IR luminosity may be due to normal star formation or triggered by interaction or active galactic nuclei (AGNs). The AGNs and interacting/merging systems among the nearest BIG objects are the most interesting cases: they provide understanding of the properties of activity, starburst, and interaction phenomena and their interrelation, thus allowing a study of the physics and evolution of galaxies in the Local Universe.

Mass-to-Light Ratio Measurements of Galaxies, Groups, and Clusters using the Numerical Action Method

The numerical action variational method (NAM) is an elegant, non-chaotic technique for calculating the trajectories of gravitating systems in a cosmological context. It has been used extensively for establishing orbits of Local Group galaxies in a series of papers (Peebles 1989, 1990, 1994, 1995) and for the Local Supercluster (Shaya, Peebles, & Tully 1995).Our repertoir of tools include code that holds present distances constant and predicts possible redshifts, one that holds present redshifts constant and predicts possible distances, and one that varies masses of each mass tracer and simultaneously satisfies both distance and redshift.Our results indicate a Ω0 = 0.2, a mass-to-light ratio of field galaxies in the range of 100 M⊙/L⊙ in blue light (t0 = 11 Gyr with no cosmological constant), but for the Virgo Cluster, the value is 6 or 7 times higher. The higher values of Ω0 determined from using the IRAS galaxy distributions may be a result of under weighting this important mass component of the universe plus a poor correlation between cluster and field galaxy distributions.

Star-Forming Activity in Arp-Madore Galaxies

The rate of star formation is enhanced in many galaxies that show disturbed morphology and/or evidence of interaction. However, the physical explanation of this connection has proved elusive, since it appears that peculiar morphology of a specific type is neither necessary nor sufficient to promote star formation. To explore the relation between star formation rates and galaxy morphology we have selected a sample of galaxies from the Arp-Madore Catalogue of Southern Peculiar Galaxies and Associations (AMC) and the Principle Galaxy Catalogue (PGC), and estimated their star formation rate using the far-infra-red (FIR) power listed in the QMW IRAS Galaxy Catalogue (QMCIGC). There are 933 objects common to all three catalogues, potentially providing the necessary data for the peculiar galaxies.