Spectral study of BIG objects on the 2.6-m telescope at the Byurakan astrophysical observatory

Results of spectral observations of 45 objects from the BIG sample (corresponding to 35 IRAS sources) obtained on the 2.6-m telescope at the BAO are reported. Emission lines are observed for 42 galaxies, 1 object is an absorption galaxy, and 2 turned out to be stars. The red shifts are determined, the radial velocities, distances, sizes, and absolute stellar magnitudes are calculated, the parameters of the spectral lines are determined, the objects are classified according to their activity type, and the IR and far IR luminosities are calculated. Of the 42 emission galaxies, 1 was type Sy2, 2 were LINERs, 1 was an AGN (Sy2 or LINER), 4 were composite, 25 were HII (including 6 with nuclear star-formation activity), and 9 were Em of undetermined type (3 of which may be AGN). Calculations show that 23 of the objects are LIG. A physical coupling is discovered for 9 multiple systems. Spectra of some of the galaxies are shown. __________ Translated from Astrofizika, Vol. 49, No. 1, pp. 23–40 (February 2006).     

Spectroscopic Study of Multiple IRAS Galaxies

Spectroscopic observations by the 2.6 m BAO telescope of IRAS galaxies identified on the basis of the First Byurakan Survey (BIG objects) are reported. Slit spectra were obtained for 16 objects, including components of 7 multiple systems and 2 individual galaxies. The red shifts were measured, and the radial velocities, distances, absolute stellar magnitudes, and infrared and far infrared luminosities were calculated. A diagnostic diagram has been constructed based on the intensity ratios of emission lines and the activity types of the objects have been determined. Two LINERs, five galaxies with composite spectra (Comp, one of which has Sy2 features) and seven HII regions were found. Two objects are ultraluminous IR galaxies (ULIG). It is shown that all the multiple systems are physical pairs or groups. The observed high IR luminosity confirms the view that ULIG/HLIGs may be associated with interactions of galaxies.     

Study and Classification of SDSS Spectra for Byurakan–Iras Galaxies

The sample of Byurakan–IRAS galaxies (BIG) has been created based on optical identifications of IRAS Point Source Catalog (PSC) at high galactic latitudes. As a result, 1178 galaxies have been identified. 172 of them have been observed spectroscopically with Byurakan Astrophysical Observatory (BAO, Armenia) 2.6 m, Special Astrophysical Observatory (SAO, Russia) 6m and Observatoire de Haute Provence (OHP, France) 1.93 m telescopes. Later on, spectra were obtained for more 83 BIG objects in Sloan Digital Sky Survey (SDSS). We have extracted and studied these spectra, classified them and measured spectral features. Diagnostic diagrams have been built to distinguish starbursts (SB), LINERs and Seyfert galaxies. Cross-correlations weremade for these objects with multiwavelength (MW) catalogues and their physical properties were studied. Among these 83 objects, 55 HII, 8 Seyfert galaxies, 2 LINERs, 4 other AGN, 6 composite spectrum objects, and 8 other emission-line galaxies have been revealed. Three of these objects are Ultra-Luminous InfraRed Galaxies (ULIRG).     

Optical Identification of IRAS Point Sources. Galaxies. X

The tenth list of objects from the BIG (Byurakan-IRAS Galaxies) sample, containing 104 galaxies identified with 60 point sources from the IRAS PSC catalog, is introduced. The identifications have been made in the region +69°+73° and 09^h50^m15^h20^m with an area of 107 sq.deg. The identified objects include 13 Sy candidates, 5 compact star-formation galaxies, 11 interacting pairs (including 5 merger candidates) and 1 interacting triple system, 5 LSB galaxies, and 5 groups. 21 objects are also identified with radio sources. The optical coordinates, their deviations from the IR coordinates, V stellar magnitudes, morphological types, angular sizes of the central regions, and position angles have been determined. The identified galaxies are of Sa-Sc, SB, and Irr morphological types, the optical stellar magnitudes lie in the range 15^m.0-21^m.5, and the angular sizes of the central regions lie in the range 3-32. Finding charts from the DSS2 are included for these objects.     

Optical identification of iras point sources. galaxies. v

A fifth list of objects from the BIG (Byurakan-IRAS galaxies) sample is given: 89 galaxies identified with 59 point sources from the IRAS Point Source Catalog. The identifications were based on the Digital Sky Survey (DSS), the First Byurakan Survey, blue and red maps from the Palomar Observatory Sky Survey, and infrared fluxes at 12, 25, 60, and 100 mm in the region of+65° ≤ δ ≤69δ and 5^h10^m ≤ α ≤9^h 15^m with an area of 96 deg². For the identified galaxies the optical coordinates, their departures from the IR coordinates, and the stellar V magnitudes, morphological types, angular sizes, and position angles were determined. The objects have optical magnitudes in the range of 14^m. 1-21^m.5 and angular sizes in the range of 2″-47″. The galaxies are mainly spiral in morphology. Compact galaxies and Seyfert candidates, interacting pairs, “mergers,” galaxies with companions and superassociations, groups of galaxies (including compact ones), and others are encountered, which shows the importance of these objects for the study of the relationships among the phenomena of star formation, activity, and interactions. Finder charts from the DSS are given for these objects. New designations and numbering are introduced for galaxies in the studied sample. Translated from Astrofizika, Vol. 43, No. 3, pp. 425-441, July– September, 2000. The NASA/IPAC Extragalactic Database (NED), operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.     

Investigating the central engine and excitation mechanisms of ultraluminous infrared galaxies: near-infrared spectroscopy

We present near-infrared observations of a sample of mainly interacting ultraluminous infrared galaxies, comprising H - and K -band spectra. Our main aims are to investigate the power source of these extremely luminous objects and the various excitation mechanisms of the strong molecular hydrogen emission often seen in such objects. Broadened emission lines were only detected in one object, IRAS 23498, consistent with the previous results for this galaxy. The [Si  vi ] emission line was detected in IRAS 17179 and 20210, both classified as Sy2s. Two of the samples were unclassified, IRAS 00150 and 23420, which exhibit neither [Si  vi ] emission nor broadened H  i emission. However this does not rule out the presence of an obscured AGN. Analysis of the molecular hydrogen emission showed that the major excitation mechanism for most objects was thermal. Modelling of the more luminous objects indicates that for IRAS 20210 10 per cent, and for both IRAS 23365 and IRAS 23420 30 per cent, of the 1–0 S(1) line emission has a non-thermal origin.     

Spectrophotometric Study of Galaxies with UV Excess

Results from a spectrophotometric study of 21 galaxies with UV excess are presented. The half widths (FWHM) and equivalent widths of observed spectrum lines of these galaxies, as well as the relative intensities of the emission lines observed in the spectrum of the galaxy Kaz243, are determined. It is conjectured that the latter galaxy has the properties of an Sy2 type galaxy. The electron densities and masses of the gaseous components are found for 15 galaxies, along with the masses of 8 galaxies for which the ratio M/L has been calculated. It is shown that the spectral structures of these galaxies do not depend on whether they are members of physical systems or are isolated.     

Optical Identification of IRAS Point Sources. Galaxies. IX

The ninth list of objects from the BIG (Byurakan-IRAS Galaxies) sample is presented; 87 galaxies are identified with 60 point sources from the IRAS PSC catalog in the region +69° +73° and 03^h50^m 09^h50^m with an area of 117 deg². Most of the identified galaxies are compact with bright bulges and faint peripheries. The identified objects include 7 Sy candidates, 8 interacting pairs (of which one is a merger candidate), and 6 LSB galaxies. The optical coordinates and their deviations from the IR coordinates, the V magnitudes, morphological types, angular dimensions, and position angles are given. The identified galaxies are of morphological types Sa-Sc and have optical stellar magnitudes in the range 15.5^m-21.5^m with angular sizes in the range 3-26. Finding charts from DSS2 are provided for these objects.     

Optical identification of iras point sources on the basis of low-dispersion FBS spectra. III

Part three of optically identified point sources from the IRAS Point Source Catalog contains 113 objects. The identifications were based on the Digitized Sky Survey (DSS), the First Byurakan Survey, blue and red maps from the Palomar Sky Survey, and infrared fluxes at 12, 25, 60, and 100 μm in the region of +61° ≤ δ ≤ + 65° and 11^h15^m ≤ α ≤ 18^h35^m with an area of 200 sq. deg. Of the 119 sources in this region, 6 could not be identified owing to the absence of optical counterparts with the given coordinates. For the identified objects we determined their optical coordinates, their departures from the IR coordinates, and their stellar V magnitudes, color indices (CI), and preliminary types. The objects have optical magnitudes in the range of 8ⁿ–21^m. Of the 113 objects, 31 turned out to be stars of spectral types K and M, 1 is a planetary nebula, 2 are candidates to be quasi- stellar objects, and 79 are galaxies. A list of the 48 nonstellar objects is given. The identified galaxies include Seyfert candidates, interacting pairs, galaxies with companions, superassociations, etc. The galaxies are in groups in many cases, and the IR emission may be due to heating of intergalactic matter within a group. Finder charts for these objects from the DSS are given. Translated from Astrofizika, Vol. 41, No. 2, pp. 251–262, April-June, 1998.     

Relationship between Infrared and Radio Emission of Seyfert Galaxies

The relationships between the monochromatic luminosity of Seyfert galaxies at frequencies of 0.408, 1.49, and 4.85 GHz and the integrated luminosity in the far infrared (IR) range are investigated. At all radio frequencies they are linear and equally close. Some Seyfert galaxies, of morphological types S0/a, E, and S0, have a far higher radio luminosity than Seyfert spiral galaxies with the same IR luminosity. Most of them are found to have compact central radio components. Seyfert spiral galaxies follow the same relationship between radio and IR emission as non-Seyfert spiral galaxies. The relationships between radio and IR luminosity for the individual groups of galaxies of spectral types Sy 1-Sy 1.5 and Sy 1.8-Sy 2 are also linear.     

Multiwavelength study of 230 IRAS FSC galaxies

A sample of 230 galaxies has been compiled based on their IRAS FSC fluxes to study their multiwavelength properties and carry out comparative analyses with other similar samples. To understand the nature of these galaxies, a comparison with a sample of bright ULIRGs having fluxes at 60 μm fν > 1 Jy and 14 optically faint IRAS FSC galaxies is presented. This comparison shows that galaxies found by IRAS are not always strong infrared sources and that the objects from the sample of ULIRGs represent a sample of extreme galaxies, which are very powerful infrared sources. We have confirmed the consistency between Star Formation Rates (SFRs) calibrated based on luminosities of the PAH feature at 7.7 μm and radio 1.4 GHz flux densities. We have estimated the extinction for our 230 objects using SFRs calibrated from the PAH feature compared to ultraviolet flux, which shows that only 1% of the ultraviolet continuum typically escapes extinction by dust within a starburst.     

Evolutionary unification in composite active galactic nuclei

In this paper, we present an evolutionary unification scenario, involving supermassive black holes (SMBHs) and starbursts (SBs) with outflow (OF), that seems capable of explaining most of the observational properties (of at least part) of active galactic nuclei (AGN).
The scenario includes a nuclear/circumnuclear SB closely associated with the AGN where the narrow-line region (NLR), broad-line region (BLR) and broad absorption line (BAL) region are produced in part by the OF process with shells and in compact supernova remnants (cSNRs).
The OF process in BAL quasi-stellar objects (QSOs) with extreme infrared (IR) and Fe  ii emission is studied. In addition, the Fe  ii problem regarding the BLR of AGN is analysed. The correlations between the BAL, IR emission, Fe  ii intensity and the intrinsic properties of the AGN are not clearly understood. We suggest here that the behaviour of the BAL, IR and Fe  ii emission in AGN can be understood within an evolutionary and composite model for AGN.
In our model, strong BAL systems and Fe  ii emission are present (and intense) in young IR objects. Parameters like the BALs, IR emission, Fe  ii /Hβ intensity ratio, Fe  ii equivalent width (EW), broad-line width, [O  iii ]λ5007-Å intensity and width, NLR size, X-ray spectral slope in radio quiet (RQ) AGN plus lobe separation, and lobe to core intensity ratio in radio loud (RL) AGN are proposed to be fundamentally time-dependent variables inside time-scales of the order of 10⁸ yr. Orientation/obscuration effects take the role of a second parameter providing the segregation between Seyfert 1/Seyfert 2 galaxies (Sy1/Sy2) and broad-/narrow-line radio galaxies (BLRG/NLRG).     

Optical identification of IRAS point sources on the basis of low-dispersion FBS spectra. IV

A fourth list of optically identified point sources from the IRAS Point Source Catalog, containing 34 nonstellar objects, is given. The identifications were made on the basis of the Digitized Sky Survey (DSS), the First Byurakan Survey, blue and red maps from the Palomar Sky Survey (FBS), and infrared fluxes at 12, 25, 60, and 100 μm in the region of +61° ≤ δ ≤ 65° and 11^h15^m ≤ α ≤ 18^h35^m with an area of 200 sq. deg. For the identified objects we determined their optical coordinates, their departures from the IR coordinates, their stellar V magnitudes, color indices CI, and preliminary types. The optical magnitudes of the objects are in the range 12^m.5-27^m. The identified galaxies include Seyfert candidates, interacting pairs, galaxies with companions, superassociations, etc. The galaxies are encountered in groups in many cases, and the IR emission may be due to heating of intergalactic matter within a group. Finder charts from the DDS are given for these objects. Translated from Astrofizika, Vol. 41, No. 3, pp. 359–366, July–September, 1998.     

Optical Identifications of IRAS Point Sources. Galaxies. VIII

A list of objects of the BIG (Byurakan-IRAS galaxies) sample is given: 89 galaxies identified with 55 point sources from the IRAS Point Source Catalog. The identifications were based on the Digital Sky Survey (DSS), the First Byurakan Survey, blue and red maps of the Palomar Observatory Sky Survey, and infrared fluxes at wavelengths of 12, 25, 60, and 100 mm in the region of +61° +65° and 05^h30^m 18^h 00^m with an area of 340 deg² (additional IR sources were identified). The optical coordinates of the identified galaxies, their departure from the IR coordinates, the V stellar magnitude, morphological type, angular size, and position angle were determined. The objects have optical magnitudes in the range of 12 ^m .5 - 21 ^m .5 and angular sizes in the range of 3 - 43. Finder charts for these objects from the DSS are given.     

The SCUBA Local Universe Galaxy Survey – II. 450-μm data: evidence for cold dust in bright IRAS galaxies

This is the second in a series of papers presenting results from the SCUBA Local Universe Galaxy Survey. In our first paper we provided 850-μm flux densities for 104 galaxies selected from the IRAS Bright Galaxy Sample and we found that the 60-, 100-μm ( IRAS ) and 850-μm (SCUBA) fluxes could be adequately fitted by emission from dust at a single temperature. In this paper we present 450-μm data for the galaxies. With the new data, the spectral energy distributions of the galaxies can no longer be fitted with an isothermal dust model – two temperature components are now required. Using our 450-μm data and fluxes from the literature, we find that the 450/850-μm flux ratio for the galaxies is remarkably constant, and this holds from objects in which the star formation rate is similar to our own Galaxy, to ultraluminous infrared galaxies (ULIRGs) such as Arp 220. The only possible explanation for this is if the dust emissivity index for all of the galaxies is ∼2 and the cold dust component has a similar temperature in all galaxies     . The 60-μm luminosities of the galaxies were found to depend on both the dust mass and the relative amount of energy in the warm component, with a tendency for the temperature effects to dominate at the highest L ₆₀. The dust masses estimated using the new temperatures are higher by a factor of ∼2 than those determined previously using a single temperature. This brings the gas-to-dust ratios of the IRAS galaxies into agreement with those of the Milky Way and other spiral galaxies which have been intensively studied in the submm.     

Optical Identifications of IRAS Point Sources. Galaxies. VI

A sixth list of objects from the BIG (Byurakan—IRAS galaxies) sample is given: 87 galaxies identified with 60 point sources from the IRAS Point Source Catalog. The identifications were based on the Digital Sky Survey (DSS), the First Byurakan Survey, blue and red maps from the Palomar Observatory Sky Survey, and infrared fluxes at 12, 25, 60, and 100 µm in the region of +65° +69° and 9^h15^m 14^h00^m with an area of 111 deg². We determined the optical coordinates of the identified galaxies, their departures from the IR coordinates, and their V magnitudes, morphological types, angular sizes, and position angles. The objects have optical magnitudes in the range of 12 ^m .5-21 ^m .5 and angular sizes in the range of 2-29. Finder charts from the DSS are given for these objects.     

New Spectrophotometric Data on the Nuclei of the Galaxies Kaz 26 and Kaz 73

The results of a spectroscopic study of the nuclei of the galaxies Kaz 26 and Kaz 73 are presented. The relative intensities of emission lines and the equivalent widths, halfwidths, and expansion velocities of lines at the continuum level are calculated. The electron densities and the masses of the gaseous components of their nuclei are determined. The numbers of stars generating the emission from the gaseous components and nuclei of the galaxies are also determined. The degree of ionization of the gas in each galactic nucleus is calculated. It is concluded that the nucleus of Kaz 26 resembles that of a "starburst" galaxy in its physical properties. It is shown that Kaz 73 is a liner (Sy 3).     

Identification of infrared sources in the IRAS circulars

From IRAS (Infrared Astronomical Satellite) Circulars Nos. 4 to 15, 110 infrared sources have been identified. Out of these 110 identified sources 99 are galaxies, nine are nebulae, one is a dark object, and one is a non-stellar object. Thirty-five of these galaxies, have already been studied, mostly are spiral type. The characteristics of sixty-four remaining galaxies, for which the type is not known or uncertain, are studied by compairing their colours and luminosities with known galaxies. The galaxies observed by IRAS are mostly active galaxies.     

Southern YSO GRV10 and its environment

In this paper the southern cometary nebula GRV10 and its environment are investigated. The object is connected with a molecular cloud (its dimensions are ~4 pc). 12CO (1-0) observations toward GRV10 revealed the presence of two molecular outflows (a bipolar outflow), a red and a blue-shifted outflow, which coincide in position, indicating that they are moving along the line of sight in opposite directions. Near GRV10 a bright IR star, GRV10 IR, is discovered (near the southern edge of the nebula) and since its spectra and near IR colors favor it to be a Mira type star, a distance of ~4.4 kpc can be estimated. Star GRV10 IR appears connected with the IRAS point source IRAS 10406-6256. The grouping of stars (YSOs - young stellar objects) connected with GRV10 and embedded in a dark nebulosity is also discussed. This grouping is associated with the IRAS point source IRAS 10406-6253, which has FIR colors typical for embedded, not evolved, YSOs.     

Infrared and radio features of galaxies with UV excess

This is a statistical study of galaxies with a UV excess. A sample of 702 Kazarian galaxies (KG) is used. The KGs are identified with objects from the MAPS, IRAS FSC, IRAS PSC, and NVSS catalogs. The O and E magnitudes are known for more than 92% of the KGs. It is shown that the KG sample is complete up to 16m.0 in the blue and to 16m.5 in the red. More than 36% of the KGs are identified with infrared (IR) sources at wavelengths of 12, 25, 60, and 100 m. Calculations of the far IR (FIR) luminosities show that 4% of the KGs are strong FIR emitters (L_FIR ≥ 10¹¹ L_⊙). More than 32% of the KGs have been identified as radio sources at a frequency of 1.4 GHz. A determination of the radio luminosities shows that the sample of KGs with known radial velocities include one powerful, L_R ≥ 10²⁵ W/Hz, radio object (Kaz 273) which is a BL Lac object. A close correlation (r=0.93) is bound between the FIR and radio luminosities for galaxies with a UV excess. An examination of the relationship between the FIR and radio luminosities for galaxies in different spectral classes shows that the correlation coefficient is higher (r=0.99) and the slope of the fit curve is larger (a=1.18) for Seyfert galaxies. Calculations of the logarithm of the ratio of the FIR and radio fluxes indicate that the sample includes 4 KGs with a radio excess, while there are none with an IR excess. __________ Translated from Astrofizika, Vol. 50, No. 3, pp. 369–379 (August 2007).