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Spatial distribution of galaxies in the Puppis region
We determine the spatial distribution of the galaxies located behind thepart of the zone of avoidance of the Milky Way defined by 220°
| Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
In this paper we describe the Nearby Optical Galaxy (NOG) sample, whichis a complete, distance-limited (cz<=6000 km s-1) andmagnitude-limited (B<=14) sample of ~7000 optical galaxies. Thesample covers 2/3 (8.27 sr) of the sky (|b|>20deg) andappears to have a good completeness in redshift (97%). We select thesample on the basis of homogenized corrected total blue magnitudes inorder to minimize systematic effects in galaxy sampling. We identify thegroups in this sample by means of both the hierarchical and thepercolation ``friends-of-friends'' methods. The resulting catalogs ofloose groups appear to be similar and are among the largest catalogs ofgroups currently available. Most of the NOG galaxies (~60%) are found tobe members of galaxy pairs (~580 pairs for a total of ~15% of objects)or groups with at least three members (~500 groups for a total of ~45%of objects). About 40% of galaxies are left ungrouped (field galaxies).We illustrate the main features of the NOG galaxy distribution. Comparedto previous optical and IRAS galaxy samples, the NOG provides a densersampling of the galaxy distribution in the nearby universe. Given itslarge sky coverage, the identification of groups, and its high-densitysampling, the NOG is suited to the analysis of the galaxy density fieldof the nearby universe, especially on small scales.
| An Exploration of the Tully-Fisher Relation for Extreme Late-Type Spiral Galaxies
In an earlier paper we presented new high-precision H I velocity widthmeasurements for a sample of 30 extreme late-type spiral galaxies. Herewe explore the adherence of those galaxies, as well as 17 additionalextreme late-type spirals, to the B- and V-band Tully-Fisher relationsdefined by a sample of local calibrators. In both bands we find the meanluminosity at a given line width for extreme late-type spirals to liebelow that predicted by standard Tully-Fisher relations. While many ofthe extreme late-type spirals do follow the Tully-Fisher relation towithin our observational uncertainties, most of the galaxies lie belowthe normal, linear Tully-Fisher relation, and some are underluminous bymore than 2 sigma (i.e., >1.16 mag in V). This suggests a possibledownward curvature of the Tully-Fisher relation for some of the smallestand faintest rotationally supported disk galaxies. This may be aconsequence of the increasing prevalence of dark matter in thesesystems. We find the deviation from the Tully-Fisher relation toincrease with decreasing luminosity and decreasing optical linear sizein our sample, implying that the physically smallest and faintestspirals may be a structurally and kinematically distinct class ofobjects.
| B and V CCD Photometry of Southern, Extreme Late-Type Spiral Galaxies
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114.1899M&db_key=AST
| HI Observations of Southern Extreme Late-Type Galaxies.I.An Optically Faint Sample
We have made neutral hydrogen (H I) 21 cm line observations of a sampleof 90 southern, low luminosity, extreme late-type galaxies using the 140ft (43 m) radio telescope at the National Radio Astronomy Observatory.Our targets were selected from catalogs derived from deep photographicexposures taken with Schmidt telescopes. Since our goal was to increasethe completeness of samples of small, gas-rich galaxies within the LocalSupercluster, our search for H I emission extended out to radialvelocities of 3000 km s^-1^. Our sample has a mean M_HI_, three timeslower than reported for brighter extreme late-type galaxies in the sameregion of the sky. We find that the observed M_HI_, in our sampleincreases with redshift, indicating that the sample of small, gas-richgalaxies within the Local Supercluster remains incomplete. We brieflycomment on some of the implications of our observations in terms of theH I properties and H I luminosity function of extreme late-type fieldgalaxies and on the locations of such objects within previouslycataloged groups of galaxies.
| An HI survey of late-type galaxies in the Southern Hemisphere. I - The SGC sample
The present H I survey of Southern Hemisphere late-type galaxies wascompleted at the Nancay radio telescope between 1985 and 1988 and coverslarge galaxies selected from the Corwin et al. (1985) SGC catalog. Ofthe 311 galaxies observed, only 245 were detected due to the very lowsurface brightness of the Magellanic irregulars. These determinationsare conceived as useful for the establishment of distance criteria forlate-type galaxies. A histogram is presented of the velocities for thedetected galaxies vs morphological stages; attention is given toindividual spectra for 242 galaxies in the sample.
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