The morphological and spectral investigation of the galaxies Kaz 5, Kaz 92, and Kaz 390

The results of morphological and spectral study of the galaxies Kaz 5, Kaz 92, and Kaz 390 are presented. The observations were made on the 2.6-m telescope at the Byurakan Observatory with the VAGR microlenses spectrograph. Isophotes of the images of the galaxies are constructed in the Hα, [NII] λλ6584 , 6548, and [SII] λλ6731, 6717 emission lines and in the continuum. The masses of Kaz 5 and Kaz 92 are determined to be 8.6 × 10⁸ M_⊙ and 6.1 × 10⁹ M_⊙ , respectively. The mass of the gaseous component in the centers of regions I and IV of Kaz 390, which encompass a 1 pixel area, are also determined. The morphological structure of the central region of Kaz 5 in the observed spectral range, λλ6400–6800?, differs completely from the structure of the same part of the galaxy observed with the 6-m and 2.5-m telescopes. It is shown that these differences in the structure in images of Kaz 5 are mostly explained by the comparatively low resolution of the telescope in combination with the VAGR spectrograph. Absorbing matter also contributes to this effect. It is also shown that a “deficit” of nitrogen has been observed in the region of Kaz 390 studied here (a circle of diameter 40″). Translated from Astrofizika, Vol. 52, No. 1, pp. 63–74 (February 2009).     

Data on the spectral variability of Kaz 102

Results from a spectral study of the quasar Kaz 102 are presented. It is shown that its spectrum varies as a whole; that is, the parameters of both the lines and the continuum change. Based on a comparison of results presented previously and in this paper, it is concluded that over a time of approximately 27.5 years the equivalent widths and relative intensities of the lines have increased, while their half widths have decreased. The spectral composition of Kaz 102 has also changed: new lines, HeII λ4686, [OIII] λ4363, and others, appear in spectra of 2000 and 2001 which were not observed in spectra taken in 1973. The electron density, and the mass and effective radius of the gas component are determined to be 2·107 cm-3, 2·10⁴ M_⊙, and 0.2 pc. __________ Translated from Astrofizika, Vol. 50, No. 2, pp. 161–170 (May 2007).     

Morphological and Spectral Study of the Galaxy Kaz 73

Morphological and spectral studies of the nucleus and immediately surrounding regions of the galaxy Kaz 73 are reported. The observations were made on the 2.6 m telescope at the Byurakan Astrophysical Observatory in combination with the multi-pupil VAGR spectrograph. Isophotes are constructed for monochromatic images in the Hα, [NII]λ 6584, and [SII]λ6731 lines. It is shown that the surface brightness of the nucleus in monochromatic images of these lines increases rapidly from the edge to the center, with an increase of 5^m for the Hα line. The nucleus of Kaz 73 is found to rotate clockwise about its axis, which is perpendicular to the direction of the arms of the galaxy. The extent of the nucleus in the direction of the arms is found to be a consequence of its rotation; that is, the nucleus is flattened in the direction of the poles. Overall, the nucleus of Kaz 73 has all the kinematic features of an entire galaxy. The masses of the nucleus and its gaseous component are determined to be 6.5⋅10⁸ M• and 1.9⋅10⁴ M•, respectively.__________Translated from Astrofizika, Vol. 48, No. 2, pp. 291–301 (May 2005).     

Spectral observations of galaxies with UV excess

Spectral observations of 19 galaxies with UV-excesses from Kazarian’s list are reported. The spectra were obtained with the 2.6-m telescope at the Byurakan Observatory using the SCORPIO spectral camera. A grism was used to obtain spectra in the wavelength interval λλ7420-3920 Å. 43 spectra in which emission lines are mainly observed were obtained from the 19 galaxies, except for the spectra of Kaz 21, Kaz 178, Kaz 183, and Kaz 184. The spectra of Kaz 17, Kaz 151, Kaz 153, and Kaz 357 have type Sy2 galactic features. In the spectra of the galaxies Kaz 17, Kaz 151, and Kaz 153, absorption lines are observed along with high excitation emission lines such as HeI λ5876 Å and HeII λ4686 Å. No lines were observed within the interval λλ7420-3920 Å in the spectra of the galaxies Kaz 183 and Kaz 184. __________ Translated from Astrofizika, Vol. 49, No. 3, pp. 351–358 (August 2006).     

Variability of the spectrum of the galaxy kaz 701

Results from a spectrophotometric study of the galaxy Kaz 701 are presented. Spectra of this galaxy were obtained on the 2.6-m telescope at the Byurakan Observatory with the SCORPIO spectral camera. In the spectra of Kaz 701, strong Hα, [OIII] λλ5007, 4959, and Hβ emission were observed, and the [SII]λλ6731, 6717 lines were observed with moderate intensities, while the [NII]λ6584 line was scarcely noticeable in the spectra obtained in 2004, but was much more intense in the spectra of 2009. The lines observed in the spectrum of this galaxy are typical of type Sy2 galaxies. A component was observed in the red wings of both the Hα and Hβ lines in the data of 2004, but, although these lines were stronger, these components were absent in the spectra taken in 2009. The relative intensities, equivalent widths, and half widths of these lines are given. These data, obtained in different observation periods (2004 and 2009), differ greatly; that is, the emission is variable.     

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).     

Spectral observation of the galaxy Kaz 17

The results of a spectral study of the galaxy Kaz 17 are presented. 150 lines are identified in its spectrum, of which 21 are in emission while the rest are absorption lines. These lines belong to the following elements and ions:..... and FeI. Roughly 56% of the absorption lines belong to FeI. Of the absorption lines, 10 belonging to TiI and FeI are isolated. Because of the closeness of their wavelengths, the rest merge and form separate absorption bands. 10 lines, including 8 emission lines, are unidentified in the spectrum of Kaz 17. In all, 160 lines were observed in the spectrum of Kaz 17. In terms of the structure of the emission lines, Kaz 17 can be assigned to type Sy1, and in terms of the absorption lines, it more closely resembles a normal galaxy. __________ Translated from Astrofizika, Vol. 49, No. 4, pp. 541–551 (November 2006).     

Narrow-band Emission-Line and Continuum Images of Seyfert Galaxies

We present narrow-band emission line (Hα + [N II]λλ 6548, 6583, [O III] λλ 4959, 5007)as well as green or red continuum images of selected Seyfert galaxies. The sample includes NGC 7214, IC 4218, Akn 479, Mrk 915, IC 1515 and F 348. This revised version was published online in July 2006 with corrections to the Cover Date.     

New data on the variability of the spectrum of Kaz 163

The results of new spectral observations of the Seyfert component of the close binary galaxy with UV excess Kaz 163 are presented. Two new spectra have been obtained: with the 3-m telescope of Lick Observatory in 1986 and with the 1.8-m telescope of Asiago Observatory in 1993. It is shown that there was no short-term (about one month) variability in the spectrum. The emission lines Hell 4686 and Hel 5876 strengthen significantly between 1984 and 1986.Translated fromAstrofizika, Vol. 37, No. 1, pp. 5–12, January–March, 1994.     

Observation of the [O III] 1 4363 auroral line in the spectrum of kaz 163

The results of spectroscopic observations of the nucleus of the S component of the galaxy Kaz 163, carried out on the 6-m telescope of the Special Astronomical Observatory in 1982, are presented. The equivalent widths, relative intensities, and half-widths of emission lines were determined. The electron temperature, electron density, and mass of the gaseous component of the nucleus were also determined. The half-widths and equivalent widths varied almost twofold over the time of observations from October 31, 1981, to May 28, 1982. During the same time the intensity of the [O III] λ 4363 auroral line increased fairly strongly. Translated from Astrofizika, Vol. 43, No. 2, pp. 183-189, April–June, 2000.     

Spectroscopic evolution of nova LW serpentis 1978 during its early decline

Optical spectroscopic data are presented on nova LW Serpentis 1978, obtained during its decline fromV 9.0 to ≃10.2 (compared to a value of ∼ 8.0 at recorded maximum). The spectrum and its evolution compare well with a typical nova, though the principal absorption (∼ −750 km s^−l) was very weak in comparison with the diffuse-enhanced absorption (∼ −1300 km s⁻¹). The principal absorption could be identified only in the lines of O I λλ7774, 8446, and in moderate-resolution observations of Hα. The salient features of spectral evolution follow: The near-infrared triplet of Ca n continuously weakened. O I λ8446 was always brighter than O I λ 7774, indicating continued importance of Lyman Β fluorescence. The lines due to [O I], [N II] and N n brightened considerably near the end of our observations (37 days from maximum). The Hα emission line was asymmetric all through with more emission towards the red. Its emission profile showed considerable structure. Based on the individual peaks in the Hα line profile, a kinematical model is proposed for the shell of LW Ser. The model consists of an equatorial ring, and a polar cone on the side away from the earth. The nearer polar cone did not show significant emission of Hα during our observations. The polar axis of the shell is inclined at a small angle (∼ 15‡) to the line of sight.     

The Evolution of Star-Forming Galaxies: The SFR Density of the Universe

The evolution of the Star Formation Rate (SFR) density of the Universe as a function of look-back time is a fundamental parameter in order to understand the formation and evolution of galaxies. The current picture, only outlined in the last years, is that the global SFR density has dropped by about an order of magnitude from a redshift of z∼1.5 to the current value at z=0. Because these SFR density studies are now extended to the whole range in redshift, it becomes mandatory to combine data from different SFR tracers. At low redshifts, optical emission lines are the most widely used. Using Hα as current-SFR tracer, the Universidad Complutense de Madrid (UCM) Survey provided the first estimation of the global SFR density in the Local Universe. The Hα flux in emission is directly related to the number of ionizing photons and, modulo IMF, to the total mass of stars formed. Metallic lines like [OII]λ3727 and [OIII]λ5007 are affected by metallicity and excitation. Beyond redshifts z∼0.4, Hα is not observable in the optical and [OII]λ3727 or UV luminosities have to be used. The UCM galaxy sample has been used to obtain a calibration between [OII]λ3727 luminosity and SFR specially suitable for the different types of star-forming galaxies found by deep spectroscopic surveys in redshifts up to z∼1.5. These calibrations, when applied to recent deep redshift surveys confirm the drop of the SFR density of the Universe since z∼1 previously infered in the UV. However, the fundamental parameter that determines galactic evolution is mass, not luminosity. The mass function for local star-forming galaxies is critical for any future comparison with other galaxy populations of different evolutionary status. Hα velocity-widths for UCM galaxies indicate that besides a small fraction of 10¹⁰-10¹¹ M_⊙ starburst nuclei spirals, the majority have dynamical masses in the ∼10⁹ M_⊙ range. A comparison with published data for faint blue galaxies suggests that star-forming galaxies at z∼1 would have SFR per unit mass and burst strengths similar to those at z=0, but being intrinsically more massive. This revised version was published online in July 2006 with corrections to the Cover Date.     

Emission-line CCD imaging of three southern symbiotic stars

Symbiotic stars that are strong radio sources and have cool dust emitting in the infrared are expected to have extended emission nebulae around them. In order to search for such emission nebulae, we have carried out CCD imaging of three symbiotic stars (R Aqr, RR Tel and H1-36) with narrow-band filters centred at the emission lines of [O III] λ5007, Hα λ6563, [N II] λ6584, [S II] λ6717 + 6731. RR Tel and H1-36 images do not show any extended nebulosities around them. The CCD image of the R Aqr nebulosity in the high excitation [O m] line is different from its image in Hα and the low excitation lines of [N II] and [S II] indicating ionization-stratification in the nebula. In H1-36 the optical nebulosity (if it exists) is smaller than ∽2 arcsec while the radio image size is known to be large (∽5 arcsec). This behaviour is opposite to that seen in R Aqr in which the radio emission comes from the core region of a much larger optical nebulosity. Interstellar and/or circumstellar extinctions are suggested to be responsible for this difference     

Stellar indices and kinematics in Seyfert 1 nuclei

We present spectra of six type 1 and two type 2 Seyfert galaxies, a starburst galaxy and a compact narrow-line radio galaxy, taken in two spectral ranges centred around the near-infrared Ca  ii triplet (∼8600 Å), and the Mgb stellar feature at 5180 Å. We measured the equivalent widths (EWs) of these features and the Fe₅₂ and Fe₅₃ spectral indices.
We found that the strength of the infrared Ca  ii triplet (CaT) in type 1 Seyfert galaxies with prominent central point sources is larger than what would be expected from the observed strength of the blue indices. This could be explained by the presence of red supergiants in the nuclei of Seyfert 1 galaxies. On the other hand, the blue indices of these galaxies could also be diluted by the strong Fe  ii multiplets that can be seen in their spectra.
We have also measured the stellar‐ and gas-velocity dispersions of the galaxies in the sample. The stellar velocity dispersions were measured using both the Mgb and CaT stellar features. The velocity dispersion of the gas in the narrow-line region (NLR) was measured using the strong emission lines [O  iii ] λλ 5007, 4959 and [S  iii ] λ 9069. We compare the gas- and star-velocity dispersions and find that the magnitudes of both are correlated in Seyfert galaxies.
Most of the Seyfert 1 galaxies that we observe have stellar‐velocity dispersions somewhat greater than that of the gas in the NLR.     

A VLA 20 and 90 centimetre radio survey of distant A-bell clusters with central cD galaxies

A radio survey, using the Very Large Array at 20 and 90 cm λ has been carried out in the direction of 46 distant Abell clusters (0.1 ≲ z ≲ 0.3) dominated by a cD galaxy (clusters classified to be Bautz-Morgan I type). A radio source coincident with the cD galaxy was detected in 16 clusters. We find that the radio luminosity function of the cD galaxies at 20cm λ, and below the luminosityP _1.4ghz ≲ 10^24.5 W Hz^-1, is similar to that of brightest ellipticals in less clustered environments. Above this luminosity, the cDs seem to have a higher probability of becoming radio sources. The effect of optical brightness on radio emission is shown to be the same for the two classes. No significantly large population of very-steep-spectrum sources with spectral index α >1.2 (flux density ∝ frequency^-α) was found to be associated with cD galaxies. A significant negative correlation is found between the radio luminosity of the cD galaxy and the cooling-time of the intra cluster medium near the galaxy. We also present evidence that the probability of radio emission from first-ranked galaxies is dependent upon their location relative to the geometrical centres of clusters and thus related to the morphological class and the evolutionary state of the clusters. We argue that both these effects are primarily caused by the dynamical evolution of these distant clusters of galaxies.     

Oxygen abundance in giant H II galaxies

A sample of 93 emission-line high luminosity galaxies from the Sloan Digital Sky Survey (SDSS) has been investigated. Line intensities have been measured in 116 SDSS spectra. Oxygen abundance has been determined in the studied galaxies. Since the auroral line of twice ionized oxygen [O III] λ 436.3 nm cannot be detected in the spectra of the sample, the intensity ratio of nebular to auroral lines needed to determine the electron temperature is calculated using the ff-relation. The oxygen abundances obtained in SDSS high luminosity galaxies are 0.2–0.5 dex lower than the maximum attainable value. This is caused by the fact that the sample includes only the gas-rich galaxies in which intense bursts of star formation occur. The equivalent number of O7 V stars which are responsible for excitation of luminescent H II regions in the studied sample is two or three orders of magnitude more than the number of stars which cause the luminescence of the brightest H II regions in nearby galaxies, and it exceeds by one order of magnitude the number of stars which cause gas in SBS 0335-052 E to glow.     

The host galaxies of active galactic nuclei

We examine the properties of the host galaxies of 22 623 narrow-line active galactic nuclei (AGN) with  0.02 < z < 0.3  selected from a complete sample of 122 808 galaxies from the Sloan Digital Sky Survey. We focus on the luminosity of the [O  iii ]λ5007 emission line as a tracer of the strength of activity in the nucleus. We study how AGN host properties compare with those of normal galaxies and how they depend on L [O  iii ]. We find that AGN of all luminosities reside almost exclusively in massive galaxies and have distributions of sizes, stellar surface mass densities and concentrations that are similar to those of ordinary early-type galaxies in our sample. The host galaxies of low-luminosity AGN have stellar populations similar to normal early types. The hosts of high-luminosity AGN have much younger mean stellar ages. The young stars are not preferentially located near the nucleus of the galaxy, but are spread out over scales of at least several kiloparsecs. A significant fraction of high-luminosity AGN have strong Hδ absorption-line equivalent widths, indicating that they experienced a burst of star formation in the recent past. We have also examined the stellar populations of the host galaxies of a sample of broad-line AGN. We conclude that there is no significant difference in stellar content between type 2 Seyfert hosts and quasars (QSOs) with the same [O  iii ] luminosity and redshift. This establishes that a young stellar population is a general property of AGN with high [O  iii ] luminosities.     

New type of extragalactic objects?

We have reported the discovery of a population of the normal extragalactic field galaxies with the clear presence of strong FHIL (forbidden high by ionized lines) and HeII 4686 emission. In this paper we present a dozen of them extracted from the SDSS dr7. The high resolution spectra 0.86 ? /px obtained with the 6-m telescope of the Special Astrophysical observatory of Russia are introduced for one of them, SDSS J093801.63 + 135317.0 confirming the presence of strong and wide FHIL and HeII 4686 emission. These objects show typical narrow (FWHM ~ 120 - 250 km s^-1) emission lines both of HI and forbidden emission lines of [NII] 6548/84, [SII] 6717/31, [OI] 6300, [OII] 3727, and [OIII] 5007/4959 with underlying stellar absorption lines, coupled with the strong FHIL emission of [FeVII] 5721, 6087, [FeX] 6375, [FeXI] 7892, [FeXIV] 5303, and HeII 4686, sometimes very broad up to 1500 km s^-1. Following the direct images, all morphological types are introduced, spherical, elliptical, spiral, barred spiral, etc., without morphological or other peculiarity and any signs of "standard" AGN activity. None of them are X-ray source. The appearance of the FHIL emission in normal galaxies (the objects of SBN/HII/ELG spectral types) might be one of the important sign of the beginning of the AGN activity. The existence of the numerous normal extragalactic objects with FHIL and HeII 4686 emission tell us that the link between the AGNs and the normal galaxies perhaps might be realized with the FHIL flare in normal galaxies. For all of them, the existence of the nonthermal source in normal galaxies should be proposed.     

A new look at the isotropy of narrow-line emission in extragalactic radio sources

We undertake a quantitative investigation, using Monte Carlo simulations, of the amount by which quasars are expected to exceed radio galaxies in optical luminosity in the context of the 'receding torus' model. We compare these simulations with the known behaviour of the [O  III ] λ5007 and [O  II ] λ3727 emission lines and conclude that [O  III ] is the better indicator of the strength of the underlying non-stellar continuum.     

Nuclear spectra of polar-ring galaxies

We report the results of spectroscopic observations of eight southern polar-ring galaxies (PRGs), in the wavelength range 5900–7300 Å. We find that five out of eight galaxies contain LINERs or Sy nuclei. Taking into consideration all PRGs with available spectral data, we estimate that about half of all PRGs and PRG candidates have either LINER or Seyfert nuclei. The observed widths of the [N  ii ] λ 6583 line in the nuclei of early-type PRGs follow the linewidth–absolute luminosity relation for normal E/S0 galaxies. We found that one of the observed galaxies – ESO 576-G69 – is a new kinematically-confirmed polar-ring galaxy with a spiral host.