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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.
| High and Low Surface Brightness Galaxies in the Local Universe. V. Optical and H I Properties
Using optical spectra of the nuclei of 250 galaxies chosen from theAutomated Plate Measuring Facility (APM) survey of UK Schmidt plates, wederive synthetic B-V and V-R colors, estimates of reddening from Balmerdecrements, metallicity via oxygen abundance, and star formation ratefrom the Hα luminosity. We also present mass-to-light ratios andgas mass fractions from 21 cm H I measurements of 238 APM surveygalaxies, 101 of which also have optical spectra. This sample ofgalaxies spans a large range in surface brightness, from high surfacebrightness irregular galaxies down to the kind of low surface brightness(LSB) galaxies that are missing from most magnitude-limited catalogs.The generally blue global colors are best explained by a combination oflow metallicity and active star formation, primarily because of thetremendous scatter in metallicity versus B-V. Optical spectra show thepresence of G and K main-sequence stars in the nuclei of these galaxies,and the stellar mass-to-light ratios and gas mass fractions show thegalaxies as a whole to be gas-rich. LSB galaxies are most likely toexperience sporadic low levels of star formation over gigayeartimescales.
| Low Surface Brightness Galaxies in the Local Universe. I. The Catalog
Data are presented for 693 galaxies identified in a large new survey forlow surface brightness galaxies in the nearby universe (z <~ 0.1).The survey covers 786 square degrees centered on the equator, and itextends significantly the surface brightness range of galaxy surveys inwhich there are a substantial number of galaxies with redshifts. Thedata are derived from the Automated Plate Measuring machine scans ofsurvey plates from the UK Schmidt Telescope and from follow-upobservations at radio and optical wavelengths. Accurate positions, totalB magnitudes, surface brightness parameters, and angular sizes aretabulated for each galaxy. Radial velocities, optical luminosities, andneutral hydrogen masses are listed for a subset of the sample. Findingcharts are also presented for those objects having a large enoughangular size that the scans from survey plates provide somemorphological information. The selection function and the luminosityfunction that can be derived from the survey are discussed in twocompanion papers.
| An image database. II. Catalogue between δ=-30deg and δ=70deg.
A preliminary list of 68.040 galaxies was built from extraction of35.841 digitized images of the Palomar Sky Survey (Paper I). For eachgalaxy, the basic parameters are obtained: coordinates, diameter, axisratio, total magnitude, position angle. On this preliminary list, weapply severe selection rules to get a catalog of 28.000 galaxies, wellidentified and well documented. For each parameter, a comparison is madewith standard measurements. The accuracy of the raw photometricparameters is quite good despite of the simplicity of the method.Without any local correction, the standard error on the total magnitudeis about 0.5 magnitude up to a total magnitude of B_T_=17. Significantsecondary effects are detected concerning the magnitudes: distance toplate center effect and air-mass effect.
| Galaxy redshifts in an equatorial field in Virgo and the spatial distribution of local Lyman alpha clouds
New redshifts are presented for 51 galaxies which lie in a narrow stripalong the celestial equator. The redshifts are derived from a mixture ofoptical and H I spectra; for the latter subset (37 galaxies) H I fluxesand line widths are also given. One of the two Ly-alpha clouds in theLocal Supercluster appears to be associated with a spiral galaxy,although the angular and physical separations (42 arcmin and 180 kpc)are large. The other nearby Ly-alpha cloud and the large H I cloudappear to be more isolated. None of the nine Ly-alpha clouds withvelocities between 5000-20,000 km/s are associated with any specificgalaxies, but most appear to fall within or near the large-scalestructures defined by the galaxies.
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