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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.
|Environments of Redshift Survey Compact Groups of Galaxies|
Redshift survey compact groups (RSCGs) are tight knots of N >= 3galaxies selected from the CfA2+SSRS2 redshift survey. The selection isbased on physical extent and association in redshift space alone. Wemeasured 300 new redshifts of fainter galaxies within 1 h^-1 Mpc of 14RSCGs to explore the relationship between RSCGs and their environments.Thirteen of 14 RSCGs are embedded in overdense regions of redshiftspace. The systems range from a loose group of five members to an Abellcluster. The remaining group, RSCG 64, appears isolated. RSCGs areisolated and distinct from their surroundings to varying degrees, as arethe Hickson compact groups. Among the 13 embedded RSCGs, three aredistinct from their general environments (RSCG 9, RSCG 11, and RSCG 85).
|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.
|The nature of elongated ellipticals|
We have analyzed the isophotal shapes of a sample of 63 elongatedelliptical galaxies, previously classified E4, 5, 6 or 7. We sorted themaccording to their isophotal class, defined by the type of deviationsfrom perfectly elliptical isophotal contours. These deviations areexpected to appear clearly, because of the very favorable orientation ofthese galaxies. We find the following results, after exclusion of 6non-elliptical galaxies: A large percentage (56%) of elongated E's aredisky objects with pointed isophotes, while only 35% have either boxy orirregular isophotes, in equal proportions, and the remaining 6 galaxies(10%) are diffucult to classify. Furthermore, 38% of disky Es's alsoshow slightly boxy spheroids. In almost all the galaxies of the sample,there is an angular range where the deviations are of the disk-type. Thefour galaxies not showing this effect are among the roundest ones in thesample, which suggests that projection effects hide detailed structuresof this kind in many ellipticals. The correlations already reported inthe literature between isophotal class and radio, X-ray emission andkinematical behavior are confirmed. In particular, there is a clear-cutcorrelation between velocity anisotropy and isophotal shape. The mostelongated Hubble types tend to be disky E's. Boxy/irregular E's rarelyexceed ellipticities of 0.45 while the maximum ellipticity of half ofthe disky Es's exceeds this value. These results confirm the dichotomyof E's, which fall roughly into two classes, disky and boxy/irregularellipticals. They also show a physical continuity between disky E's andSO's and suggest that the Hubble types are strongly correlated withdisk-to-bulge ratios throughout the Hubble sequence, even at itsearly-type end (round E's), for which the disk is hidden by orientationeffects Galaxies escaping the correlations are the boxy/irregular Es's,resulting probably from strong merging processes.
|General study of group membership. II - Determination of nearby groups|
We present a whole sky catalog of nearby groups of galaxies taken fromthe Lyon-Meudon Extragalactic Database. From the 78,000 objects in thedatabase, we extracted a sample of 6392 galaxies, complete up to thelimiting apparent magnitude B0 = 14.0. Moreover, in order to considersolely the galaxies of the local universe, all the selected galaxieshave a known recession velocity smaller than 5500 km/s. Two methods wereused in group construction: a Huchra-Geller (1982) derived percolationmethod and a Tully (1980) derived hierarchical method. Each method gaveus one catalog. These were then compared and synthesized to obtain asingle catalog containing the most reliable groups. There are 485 groupsof a least three members in the final catalog.
|Isophotal shapes of early-type galaxies. I - Elongated ellipticals|
Forty-three very elongated elliptical galaxies were observed in directB, V, R CCD imaging with the 2-m telescope of Pic-du-Midi Observatoryand with the Canada-France-Hawaii telescope in fairly good seeingconditions. Five galaxies do not show an elliptical structure: threeclearly show spiral features and one is a dumbbell. The 38 othergalaxies were analyzed with an isophote-fitting procedure which allowsone to derive the deviations from pure ellipses in terms of thecoefficients of a Fourier series. The geometrical parameters of these 38elongated ellipticals are presented, with brief comments on theirpeculiarities.
|Associations between quasi-stellar objects and galaxies|
A table is presented here listing all close pairs of QSOs and galaxiesthat were found in a computer-aided search of catalogs of QSOs andbright galaxies and an extensive search of the literature. There is alarge excess of pairs with separations of 2 arcmin lor less, or about 60kpc, over the numbers expected if the configurations were accidental.The angular separation for 392 pairs adds to the evidence for physicalassociation, and it is shown that selection effects are not important. Ageneral rule is stated that QSOs tend to lie in the vicinity of normalgalaxies much more often than is expected by chance whether or not thegalaxies and the QSOs have the same redshifts. It is emphasized thatthis rule cannot be explained in terms of gravitational microlensing,and it is concluded that some part of the redshift of all classes ofactive nuclei is not associated with the expansion of the universe.
|Linear clusters of galaxies - A194|
New measurements for 160 redshifts and previous measurements for 108other redshifts are presented for galaxies within 5 deg of A194. Thegalaxy distribution in A194 is shown to be inconsistent with aspherically symmetric King model. A mass-to-light ratio is derived usingthe virial theorem which is lower than the mean for the groups in theCfA redshift survey (Huchra and Geller, 1982; Geller, 1984). Anonparametric test for galaxy-cluster alignment and a Chi-squared testare used to search for alignment of galaxy major axes with the axis ofA194. Evidence for neither luminosity segregation nor significantdifferences in the velocity or surface distributions of galaxies as afunction of morphological type is found.
|Errors in the 21-cm redshifts of galaxies - A statistical analysis|
A list of 98 galaxies with the most accurate 21-cm radial velocities sofar determined is provided. These galaxies are the 'standard' onesavailable to date. The data are weighted means of redshiftdeterminations, extracted from a data set of about 2500 21-cm redshiftmeasurements. The mean error and 99 percent confidence limit of thesestandards are less than or equal to 10 km/s and less than or equal to 50km/s, respectively. Statistical mean error analysis of the data showsthat the accuracy of the redshift estimate is an increasing function ofthe morphological type of the galaxy i.e., from early to late types. Forthe galaxies in common, statistical comparisons between the present dataand two other samples of 21-cm radial velocities show good agreement.Furthermore, systematic errors of instrumental origin do not seem to bestatistically significant.
|A survey of galaxies in the field of A194|
The galaxies in the field of the cluster Abell 194 have been surveyedusing glass plate copies of the Palomar Observatory Sky Survey. Thedistribution in the sky of the diameter-limited galaxy sample has aposition angle of 128 deg and an axial ratio of 0.72. These measurementssuggest that the line of bright galaxies at the cluster center could bea bar of an overall larger filamentary structure, as in a barred spiralgalaxy. Although no statistically significant deviation from random isfound, the galaxy position-angle distribution shows a tendency to lineup along the central bright galaxy line and at right angles to it. Thelatter direction coincides with the position angle determined for theentire sample. For disk galaxies, there is a statistically significantdeviation of the observed axial-ratio distribution from the BdVcomparison sample. An excess of edge-on galaxies and a deficiency ofgalaxies at intermediate axial ratios is found.
|A catalog of morphological types in 55 rich clusters of galaxies|
Data are presented from a study of 55 rich clusters of galaxies. Thedata include positions, morphological types, estimated total magnitudes,bulge sizes, and ellipticities for about 6000 galaxies, as determinedfrom high scale photographic plates. Data reduction procedures aredescribed, and a brief analysis of cluster richness, which indicatesthat Abell richness classes are only rough indicators of total clustermembership, is included.
|Low-Dispersion Spectra of Galaxies III. Abell No. 194|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973PASP...85..104P&db_key=AST
|Spectra and Other Characteristics of Interconnected Galaxies and of Galaxies in Groups and in Clusters. III.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1964ApJ...139..269Z&db_key=AST
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