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|Physical Coupling of Kazarian Galaxies with Surrounding Galaxies|
Results from a statistical study of Kazarian galaxies and the objectssurrounding them are presented. It is shown that: (1) the sample ofKazarian galaxies up to 16m.0 is complete. (2) Roughly 35.7% of theKazarian galaxies are members of clusters, 14.0% of groups, and 13.6% ofbinary systems, while 36.7% are single galaxies. (3) Of the 580 Kazariangalaxies, roughly 61.2% are infrared, 8.8% radio, and 2.8% x-raysources. (4) The relative numbers of Kazarian galaxies for completesamples of I, R, and X in the different groups are systematically higherthan the corresponding numbers for samples of all Kazarian galaxies.
|The ROSAT/IRAS Galaxy Sample Revisited|
Galaxies in the ROSAT/IRAS sample were selected by their soft X-ray(0.1-2.4 keV) and far-infrared (lambda = 60 μm) emission. Therelatively large uncertainties in the original ROSAT and IRAS positionscaused some contamination by close pairs and forced the exclusion ofmost ``high-flux'' (S > 10 Jy at lambda = 100 μm) IRAS sourcesfrom the original sample. We used new 1.4 GHz VLA images of all objectsnorth of delta = -45 deg along with improved X-ray and far-infraredpositions to eliminate incorrect identifications, many of which appearedto be starburst galaxies with high X-ray luminosities, log [X(ergs^-1)]> 43. We also used VLA images to search for new X-ray identificationsamong the ``high-flux'' sources with delta > -45 deg. Only two werefound, indicating that luminous starburst galaxies have relatively lowsoft X-ray luminosities, in part due to absorption by a denseinterstellar medium. No starburst galaxies in our revised sample haveX-ray luminosities approaching log [X(ergs^-1)] = 43. We conclude thatmost galaxies in the revised ROSAT/IRAS sample contain X-ray-emittingactive galactic nuclei (AGNs) residing in star-forming disks that emitmost of the lambda = 60 μm radiation. Normal and starburst galaxiesprobably do not account for a significant fraction of the soft X-raybackground.
|A catalogue of spatially resolved kinematics of galaxies: Bibliography|
We present a catalogue of galaxies for which spatially resolved data ontheir internal kinematics have been published; there is no a priorirestriction regarding their morphological type. The catalogue lists thereferences to the articles where the data are published, as well as acoded description of these data: observed emission or absorption lines,velocity or velocity dispersion, radial profile or 2D field, positionangle. Tables 1, 2, and 3 are proposed in electronic form only, and areavailable from the CDS, via anonymous ftp to cdsarc.u-strasbg.fr (to184.108.40.206) or via http://cdsweb.u-strasbg.fr/Abstract.html
|Rotation Curves and Velocity Measures for Spiral Galaxies in Pairs|
Rotation curves have been obtained for 76 spiral galaxies in pairs,including a geometrically selected subset from the Karachentsev catalogand a set of Seyfert galaxies with close companions. Derived parametersof the rotation curves and the galaxies light distributions are alsopresented. The rotation curves are classified broadly by shape, withspecial emphasis on kinematic disturbances and regions of solid-bodybehavior that may lead to bar development. Broadband images of thegalaxies allow assessments of their degree of symmetry or disturbance.These velocity slices afford an empirical basis for evaluating theaccuracy of radial velocity measures for spiral galaxies in pairs, andthe dynamically important radial velocity differences. Specifically, thedisagreement among several plausible ways of estimating the centralvelocity from these rotation data is used to estimate how closely any ofthese might approximate the nuclear or center-of-mass values. From sevenindicators of central velocity, the internal scatter is σ_vv_ = 34km s^-1^. Of these, the velocity weighted by Hα intensity alongthe slit shows a systematic offset of about 20 km s^-1^ with respect tothe others for the Karachentsev pairs, in the sense that this measure isredshifted with respect to the other indicators. This is in the sense(but not of the total magnitude) required to account for statisticalasymmetries in pair velocity differences. Individual scatter between thevelocity indicators taken pairwise ranges from σ = 20 to 52 km s^-1^. These results imply that emission-line data such as these cannotspecify the center of mass or nuclear redshift at a level more accuratethan this, even for arbitrarily precise velocity measurements, becauseit is not clear how the observed quantities relate to the desiredmeasurement in a physical sense. No useful predictor of which galaxieshave large or small scatter among velocity measures was found, exceptthat the scatter is small for the class of "nonrotating" galaxies withsmall overall velocity amplitudes. Projected separation, separationnormalized to disk scale length, and morphological disturbance do notcorrelate with the velocity scatter.
|Morphological classification of new galaxies with a UV excess|
The results of a morphological classification of 580 galaxies with a UVexcess, included in the lists in [M. A. Kazarian, Astrofizika,15, 5(1979); ibid.,15, 193 (1979); M. A. Kazarian and É. S. Kazarian,ibid.,16, 17 (1980); ibid.,18, 512 (1982); ibid.,19, 213 (1983)], arepresented. For this we have developed a set of symbols, using the typesE, S, and Ir introduced by Hubble, as well as symbols introduced byother authors and us. This set enabled us to make the morphologicalclassification. Direct photographs obtained on the 2.6-m and 6-mtelescopes were used to classify 141 of the galaxies (over 24%), whilePalomar Atlas charts were used for the remaining 439 galaxies. Thesegalaxies were divided into two groups based on classificationconditions, and data on each group are given in Tables 1 and 2,respectively. The results for each group, given in Table 3, show thatwith the transition from early types, such as C and E, to later types,such as S and Ir, the relative number of galaxies going into one group(Table 1), in which the classification was based on direct photographs,increases in comparison with the number going into the other group(Table 2).
|A spectrophotometric and morphological study of UV-excess galaxies in whose spectra only absorption lines are observed|
We present the results of a spectral and morphological study of 13UV-excess galaxies in whose spectra only absorption lines are observed.We determine the equivalent widths and FWHM of the lines. We concludethat these objects are in an evolutionary stage between UV-excessgalaxies with emission lines and normal galaxies.
|Kinematic regulation of star formation in interacting galaxies|
Kinematic data for a geometrically-selected set of spiral galaxies inpairs are presented, and analyzed for correlations between indicators ofstar formation and indices of orbital type and extent of kinematicdisturbance. Both nuclear and global star formation rate are connectedto kinematic disturbance with the kind and degree of disturbance moreimportant than either projected separation or relative directions ofgalaxy spin and companion orbit. Enhanced star formation is found forgalaxies with large areas of solid-body rotation and for galaxies withmore general kinds of disturbed velocity structure, with the highestlevels occurring in a set of galaxies distinguished by anomalously smalloverall velocity amplitude. The strongest correlation is between starformation rate (SFR) and amplitude of velocity disturbance, fromrotation curves, when the velocity disturbance is scaled by the galaxyrotation velocity. Triggered star formation is more sensitive to galaxydynamics than to strictly local phenomena such as cloud disruptionvelocities. Comparsion with various models for the enhanced SFR ininteracting systems shows that cloud-collision processes cannot accountfor the strong starbursts in retrograde systems, and models relying oninteractions between different phases of the interstellar mediumsimilarly require too many direct collisions between galaxy disks.Schemes involving gravitational instability of the disk driven initiallyby the external perturbation fare best; such instability can then drivethe rates of other processes such as cloud collisions, possibly in acascadelike series. Solid-body kinematics appear more important than thepresence of a stellar bar in this connection. Using a new set ofclassifications from uniform CCD images, there is a better correlationbetween disturbed kinematics and morphological disturbance of individualgalaxies than with pair interaction types in the Karachentsev catalog,though the relationship is not one-to-one. There is a substantialpopulation of pairs with disturbed kinematics but not disturbed forms.The kinds of disturbance found from direct and retrograde encountersmatch well the predictions of n-body calculations for each kind ofencounter.
|HI observations of galaxies in nearby Zwicky clusters|
The results of a long term project of H I observations of galaxieswithin the boundaries of nearby Zwicky clusters are presented. Thedetection rate is rather low (233 out of 618, i.e., 38 percent) ascompared to other surveys carried out recently. Most of the radialvelocities of the detected galaxies are new determinations. The largespread in radial velocities for many of these clusters is a strongindication for the presence of several foreground and/or backgroundgalaxies.
|Spectrophotometry of Galaxies with Ultraviolet Excess - Part Nine|
|Morphological investigation of galaxies with ultraviolet excess|
Large-scale photographs of 43 galaxies with UV excess from the lists ofKazarian (1979) and Kazarian and Kazarian (1980), obtained in 25-minexposures at 20 arcsec/mm with the 2.6-m reflector at BiurakanAstrophysical Observatory during summer, 1980, are presented andcharacterized in terms of morphology. The majority of the galaxies arefound to have well defined nuclear regions or condensations; about 60percent are classified as spirals, 25 percent as ellipticals, and 15percent as compact. Isodensity charts of eight galaxies are included.
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