Upload your image
DSS Images Other Images
Submit a new article
|The Southern Dwarf Hunt: Local Group Dwarf Candidates in the Southern Sky|
We present observations of 82 Local Group dwarf galaxy candidates, ofwhich 62 were chosen visually from ESO-SRC survey plates of the southernsky (32 of which were not previously cataloged) and the rest suggestedby various sources in the literature. Two are the Local Group galaxiesAntlia and Cetus; nine are more distant galaxies, though still within afew megaparsecs; 45 are background galaxies; seven are planetary (orother emission) nebulae; 15 are reflection or other Galactic nebulae;two are galaxy clusters; one is a Galactic star cluster; and one is amisidentified star. We conclude that there is no large population offaint Local Group dwarf galaxies of any familiar type awaitingdiscovery. We point out the danger of relying on a single type of datato reach conclusions about an object. Based on observations made withthe Isaac Newton Telescope, operated on the island of La Palma by theIsaac Newton Group in the Spanish Observatorio del Roque de losMuchachos of the Instituto de Astrofísica de Canarias, and onobservations made at Cerro Tololo Interamerican Observatory (CTIO). CTIOis operated by the Association of Universities for Research inAstronomy, Inc. (AURA), under a cooperative agreement with the NationalScience Foundation as part of the National Optical Astronomy Observatory(NOAO).
|Dynamics of the Pavo-Indus and Grus clouds of galaxies|
A study of groups of galaxies in the above regions was carried out byselecting a sample extending one magnitude deeper than previous work inthe area, complete down to 15 mag. We report new redshift determinationsfor 58 galaxies in the region and 13 other miscellaneous galaxies, basedon La Silla observations. Using a total of 266 galaxies with measuredredshifts in the Pavo-Indus and Grus clouds, we perform a new analysisof groupings following a well-tested algorithm. A total of 18 groups issingled out, most of them known from previous work, even though a fewadditional members are added. For all the groups, we have calculateddynamical parameters and M/L ratios. All groups are found to be boundaggregates, but only one group can be virialized. For the six mostpopulated examples, having at least five members, we also calculateseveral mass estimators and discuss the wide range of observed M/Lratios, which extends from nine to nearly 500 M(solar)/L(solar). Weintroduce two parameters to measure the presence of either a dominantgalaxy or internal subcondensations, respectively, and test whether anycorrelation with the M/L ratios can be detected. No clear correlationsare found.
|Nearby galaxies. I - The catalogue|
The data of 289 nearby galaxies have been compiled. The inclusion of agalaxy into the catalog depends on its redshift as in the catalogue ofKraan-Korteweg and Tammann (1979) or on the fact that the objects areknown to be certain or probable members of nearby groups. The galaxiesin the sample form the Local Group with 51 certain and probable membersand several additional groups. One third of the galaxies in the catalog(96 objects) does not seem to belong to any group. The main emphasis isto get a distance-limited sample of galaxies, especially of dwarfobjects.
|Dynamics of clusters of galaxies with central dominant galaxies. I - Galaxy redshifts|
Optical redshifts are presented for a sample of 638 galaxies in thefields of the clusters Abell 85, DC 0107-46, Abell 496, Abell 2052, andDC 1842-63. The velocity histograms and wedge diagrams show evidence fora foreground sheet of galaxies in Abell 85 and background sheets ofgalaxies in DC 0107-46 and Abell 2052. The foreground group projectedagainst the center of Abell 85 found by Beers et al. (1991) isconfirmed. No evidence of substructure was found in Abell 496, Abell2052, and DC 1842-63. The clusters have global velocity dispersionsranging from 551 km/s for DC 1842-63 to 714 km/s for A496, and flatdispersion profiles. Mass estimates using the virial theorem and theprojected mass method range from 2.3 x 10 exp 14 solar masses for DC0107-46 to 1.1 x 10 exp 15 solar masses for A85.
|Photometric properties of galaxies in the cluster DC 1842-63|
Results are presented from photometric and kinematic observations of thecluster DC 1842-63, including total magnitudes for 174 galaxies, surfacephotometry and bulge-to-disk ratios for 31 galaxies, and redshiftsmeasurements for 20 galaxies. The mean cluster velocity is found to be4437 + or - 78 km/s with a cluster velocity dispersion of 507 km/s. TheX-ray luminosity of the cluster is shown to be 3.0 X 10 to the 43rderg/s in the 0.5 and 4.5 keV band.
|Galaxy evolution and large-scale structure in the far-infrared. I - IRAS pointed observations|
Redshifts for 66 galaxies were obtained from a sample of 93 60-micronsources detected serendipitously in 22 IRAS deep pointed observations,covering a total area of 18.4 sq deg. The flux density limit of thissurvey is 150 mJy, 4 times fainter than the IRAS Point Source Catalog(PSC). The luminosity function is similar in shape with those previouslypublished for samples selected from the PSC, with a median redshift of0.048 for the fainter sample, but shifted to higher space densities.There is evidence that some of the excess number counts in the deepersample can be explained in terms of a large-scale density enhancementbeyond the Pavo-Indus supercluster. In addition, the faintest counts inthe new sample confirm the result of Hacking et al. (1989) that faintIRAS 60-micron source counts lie significantly in excess of anextrapolation of the PSC counts assuming no luminosity or densityevolution.
Submit a new link
Member of following groups:
Observation and Astrometry data
Catalogs and designations: