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The UZC-SSRS2 Group Catalog
We apply a friends-of-friends algorithm to the combined Updated ZwickyCatalog and Southern Sky Redshift Survey to construct a catalog of 1168groups of galaxies; 411 of these groups have five or more members withinthe redshift survey. The group catalog covers 4.69 sr, and all groupsexceed the number density contrast threshold, δρ/ρ=80. Wedemonstrate that the groups catalog is homogeneous across the twounderlying redshift surveys; the catalog of groups and their membersthus provides a basis for other statistical studies of the large-scaledistribution of groups and their physical properties. The medianphysical properties of the groups are similar to those for groupsderived from independent surveys, including the ESO Key Programme andthe Las Campanas Redshift Survey. We include tables of groups and theirmembers.
| Galaxy coordinates. II. Accurate equatorial coordinates for 17298 galaxies
Using images of the Digitized Sky Survey we measured coodinates for17298 galaxies having poorly defined coordinates. As a control, wemeasured with the same method 1522 galaxies having accurate coordinates.The comparison with our own measurements shows that the accuracy of themethod is about 6 arcsec on each axis (RA and DEC).
| Arm structure in normal spiral galaxies, 1: Multivariate data for 492 galaxies
Multivariate data have been collected as part of an effort to develop anew classification system for spiral galaxies, one which is notnecessarily based on subjective morphological properties. A sample of492 moderately bright northern Sa and Sc spirals was chosen for futurestatistical analysis. New observations were made at 20 and 21 cm; thelatter data are described in detail here. Infrared Astronomy Satellite(IRAS) fluxes were obtained from archival data. Finally, new estimatesof arm pattern radomness and of local environmental harshness werecompiled for most sample objects.
| 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.
| An observational study of the dynamics of binary galaxies
The single velocity measurement rms error value in the present set ofradial velocities for all galaxies in the Turner (1976) catalog of 156binary systems is estimated t be 29 km/sec. Typical velocity differencesare very small, with half of the 55 systems in the subsample of isolatedspiral-spiral pairs (the most reliable set of 'pure' binaries) havingmeasured velocity differences of less than 75 km/sec. By means of MonteCarlo simulations of scale-free ensembles of binary galaxies, it ispossible to show that the present data's independence of eitherluminosity or projected separation is inconsistent both with thehypothesis that the mass of binary systems increases linearly withluminosity, and that galaxies in pairs may effectively be treated aspoint masses. The data favor models in which galaxies interact through aquasi-isothermal potential only weakly depending on luminosity.
| Flocculent and grand design spiral structure in field, binary and group galaxies
A 12-division morphological system emphasizing arm continuity, lengthand symmetry has been developed for the classification of all spiralgalaxies according to the regularity of their spiral arm structure. Armclassifications were tabulated for 305 barred and nonbarred spiralgalaxies; of these, 79 are isolated, 52 are binary and 174 are ingroups. Among the isolated SA galaxies, 68 + or - 10% have irregular andfragmented, or 'flocculent', spiral structures. Only 32 + or - 10% havesymmetric spiral arms in the classic grand design pattern. Flocculentspirals are the most common structures of galaxies without companions orbars. Since flocculent galaxies may have bars and companions, and granddesign galaxies may have neither bars nor companions, such perturbationsare neither perfectly effective nor always necessary in the driving ofgrand design patterns.
| Double galaxy investigations. I - Observations
Redshift information from 240 A/mm spectrograms is presented for 370double arcsec galaxy systems from the Karachentsev (1972) catalog,including all pairs in that catalog with separation less than 80 arcsec.An extensive error discussion utilizing internal and external (21 cm)comparisons provides calibration of systematic error and determines theuncertainty for a typical high weight optical redshift to be plus orminus 65 km/sec. Internal differential redshifts within single spectrausing common lines achieve accuracies of 18-30 km/sec, depending uponseparation, and are available for about 200 pairs. Extensive informationon emission and other properties is also provided.
| Binary galaxie. I. A well-defined statistical sample.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976ApJ...208...20T&db_key=AST
| An Isophotometric and Photographic Atlas of Peculiar Galaxies
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973ApJS...26..115S&db_key=AST
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