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|The ESO nearby Abell cluster survey. VIII. Morphological and spectral classification of galaxies|
We determine the morphological types of 2295 galaxies from the ESONearby Abell Cluster Survey (ENACS) from CCD images obtained with theDutch telescope on La Silla. A comparison with morphological types fromthe literature for 450 of our galaxies shows that the reliability of ourclassification is quite comparable to that of other classifiers. Werecalibrate the ENACS spectral classification with the new morphologicaltypes, and find that early- and late-type galaxies can be distinguishedfrom their spectra with 83% reliability. Ellipticals and S0 galaxies canhardly be distinguished on the basis of their spectra, but late spiralscan be classified from the spectrum alone with more than 70%reliability. We derive pseudo-colors and linestrengths from the ENACSspectra for the galaxies of different morphological types. We considerthe bright (MR ≤ -20) and faint (MR > -20)subsets of the galaxies without emission lines (non-ELG) separately. Wefind a strong and significant correlation between the average color andthe average strength of the metal absorption lines. The averagemetallicity decreases and the average color gets bluer towards laterHubble type. Also, the faint galaxies in each morphological class arebluer and less metal-rich than their brighter counterparts, whichextends the well-established color-magnitude relation of early-typegalaxies to (late) spirals. In view of these very strong global trends,the colors and metallicities of faint S0 galaxies and bright earlyspirals are remarkably similar. The bright early spirals may, onaverage, have somewhat stronger Hδ absorption than the othergalaxies, which could be due to recent starformation. The galaxies withemission lines (ELG) have a bluer spectral continuum than the non-ELG,and the amount of blueing hardly depends on morphological type. Thefraction of ELG depends strongly on morphological type (varying from4±1% for ellipticals to 59±4% for late spirals), but foreach of the morphological types it varies very little with projecteddistance from the cluster center.
|The Southern Sky Redshift Survey|
We report redshifts, magnitudes, and morphological classifications for5369 galaxies with m_B <= 15.5 and for 57 galaxies fainter than thislimit, in two regions covering a total of 1.70 sr in the southerncelestial hemisphere. The galaxy catalog is drawn primarily from thelist of nonstellar objects identified in the Hubble Space TelescopeGuide Star Catalog (GSC). The galaxies have positions accurate to ~1"and magnitudes with an rms scatter of ~0.3 mag. We compute magnitudes(m_SSRS2) from the relation between instrumental GSC magnitudes and thephotometry by Lauberts & Valentijn. From a comparison with CCDphotometry, we find that our system is homogeneous across the sky andcorresponds to magnitudes measured at the isophotal level ~26 magarcsec^-2. The precision of the radial velocities is ~40 km s^-1, andthe redshift survey is more than 99% complete to the m_SSRS2 = 15.5 maglimit. This sample is in the direction opposite that of the CfA2; incombination the two surveys provide an important database for studies ofthe properties of galaxies and their large-scale distribution in thenearby universe. Based on observations obtained at Cerro TololoInter-American Observatory, National Optical Astronomy Observatories,operated by the Association of Universities for Research in Astronomy,Inc., under cooperative agreement with the National Science Foundation;Complejo Astronomico El Leoncito, operated under agreement between theConsejo Nacional de Investigaciones Científicas de laRepública Argentina and the National Universities of La Plata,Córdoba, and San Juan; the European Southern Observatory, LaSilla, Chile, partially under the bilateral ESO-ObservatórioNacional agreement; Fred Lawrence Whipple Observatory;Laboratório Nacional de Astrofísica, Brazil; and the SouthAfrican Astronomical Observatory.
|The ESO Nearby Abell Cluster Survey. V. The catalogue: Contents and instructions for use|
We present the catalogue resulting from the ESO Nearby Abell ClusterSurvey (the ENACS), which contains redshifts and magnitudes for 5634galaxies in the directions of 107 rich, nearby southern Abell clustercandidates. We describe the contents of the catalogue and discuss theresults of a comparison between the ENACS catalogue and the COSMOSGalaxy Catalogue. When cross-correlating the two catalogues we findthat, at least in the areas of the ENACS clusters, the completeness ofthe COSMOS catalogue is somewhat lower than was estimated previously forthe carefully analyzed and well-calibrated part of the COSMOS catalogueknown as the Edinburgh-Durham Southern Galaxy Survey (EDSGC). The galaxypositions in the COSMOS and ENACS catalogues are found to be on the samesystem to within about one arcsecond. For the clusters for which thephotometry in the ENACS and COSMOS catalogues is based on the samesurvey plates, the two magnitude scales agree very well. We confirm thatthe photometric calibration in the EDSGC subset of the COSMOS catalogueis of higher quality than in the EDSGC complement. The ENACS galaxysamples are unbiased subsets of the COSMOS catalogue as far as theprojected galaxy distribution is concerned, except in only a few cases.We summarize how the ENACS galaxy samples are subsets of the COSMOScatalogues in the ENACS apertures, with respect to magnitude. For theENACS catalogue as a whole, we describe the apparent incompleteness atfaint magnitudes and towards higher redshifts. Finally, we provide somedetailed information about the ENACS catalogue that is essential for itsproper statistical use and we summarize some facts that must beremembered when selecting subsets of galaxies from it. Based onobservations collected at the European Southern Observatory (La Silla,Chile).
|Properties of nearby clusters of galaxies. II. A 151, A 637, A 646, A 649, A 655, A 1132, A 1314, A 1377, A 1570, A 1589.|
We present F band photometry, from digitized 48-inch Palomar plates, of1167 galaxies brighter than m_3_+3 in 10 Abell clusters. For eachgalaxy, absolute coordinates, magnitude, size, ellipticity endorientation are given. For each cluster we provide finding charts andcontour maps of the galaxy surface density.
|The morphological catalogue of galaxies equatorial survey|
We present 865 redshifts of galaxies located in the equatorial stripdelta between -17.5 deg and -2.5 deg in the right ascension rangebetween 20 h and 5 h. Redshifts have been obtained for the completesample of all 833 galaxies in the Morphological Catalog of Galaxies withmagnitudes brighter than m = 14.5 (corresponding approximately tom(Zwicky) = 15.0). This sample also includes three galaxies from othersources with more reliable magnitudes, satisfying this limit, and 29fainter galaxies, usually companions of the galaxies in the magnitudelimited sample. Our maps of a very large volume of nearby spacedemonstrate a variety of coherent large scale structures which includelarge voids, 20-50/h Mpc in diameter and large walls at least 70/h Mpcacross.
|The cluster of galaxies Abell 151|
We use a sample of 65 redshifts to study the kinematics and dynamics ofthe cluster Abell 151. Data on individual galaxies are presented, andthe accuracy of the determined velocities are discussed as well as someproperties of the cluster. The velocity data reveal a foreground groupand a background population at the same redshifts as the closelyprojected cluster A 166.
|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.
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