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IAUC 8741 available at Central Bureau for Astronomical Telegrams.
|Galaxy Luminosity Functions from Deep Spectroscopic Samples of Rich Clusters|
Using a new spectroscopic sample and methods accounting forspectroscopic sampling fractions that vary in magnitude and surfacebrightness, we present R-band galaxy luminosity functions (GLFs) for sixnearby galaxy clusters with redshifts of 4000 kms-1
|Nature and environment of Very Luminous Galaxies|
The most luminous galaxies in the blue passband have a largercorrelation amplitude than L* galaxies. They do not appear tobe preferentially located in rich clusters or groups, but a significantfraction of them seem to be in systems which include fainter members. Wepresent an analysis of fields centered on 18 Very Luminous Galaxies(MB <=-21) selected from the Southern Sky Redshift Survey2, based on new observations and public data of the 2dF Galaxy RedshiftSurvey; we present also additional data on a CfA VLG and on Arp 127. Wefind that all the selected VLGs are physically associated with faintercompanions. Moreover, there is a relation between the VLG morphology(early or late) and the dynamical properties of the system, whichreflects the morphology-density relation. 6 out of the 18 SSRS2 VLGs areearly type galaxies: 2 are in the center of rich Abell clusters withvelocity dispersion sigma ~ 600 km s-1, and the other 4are in poor clusters or groups with sigma ~ 300. The VLG extractedfrom the CfA catalog is also an elliptical in a Zwicky cluster. Theremaining 2/3 of the sample are late-type VLGs, generally found inpoorer systems with a larger spread in velocity dispersion, from ~ 100up to ~ 750 km s-1. The low velocity dispersion, late-typeVLG dominated systems appear to be analogous to our own Local Group. Thepossibile association of VLG systems with dark matter halos with masscomparable to rich groups or clusters, as suggested by the comparablecorrelation amplitude, would imply significant differences in the galaxyformation process. This work also shows that observing fields aroundVLGs represents an effective way of identifying galaxy systems which arenot selected through other traditional techniques.Figures 1, 2 and Appendix B are only available in electronic form athttp://www.edpsciences.org
|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.
|Parameters of bulges and disks of interacting galaxies|
The photometric structure of 23 interacting galaxies is analyzed. It isshown that equivalent photometric profiles, if used for statisticalanalyses of the global structure of the disks of spiral galaxies, yieldthe same results as major-axis profiles. When analyzing nonaxisymmetricand faint objects, the equivalent profiles should be preferred to boththe major-axis and elliptically averaged profiles. The studies ofintegral characteristics of bulges of interacting spiral galaxies showedthat the parameters of these objects obey the mu_e-gamma_e relation fornormal spirals over a wide range of surface-brightness (~ 10 mag) andlinear-dimension (~ 3x10^2) values. This fact may imply that stronggravitational perturbations have little effect on dense central galaxyregions, leaving the bulges in a state that is very close toequilibrium. The central parts of disks in interacting spirals are, onthe average, ~ 1 mag brighter than the corresponding regions in isolatedgalaxies, which is probably attributable to enhanced star-formationprocess. Integrated photometric parameters of the disks of localinteracting galaxies are similar to those of spiral galaxies ofcomparable size observed at z ~ 1. The latter are also characterized byhigh surface brightness. Among them, interacting or disturbed objectscomprise a sizable fraction. It may be assumed that gravitationalperturbations and external accretion contribute significantly to theobserved evolution of disk parameters in large spiral galaxies, when z ~1.
|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.
|Tidally-triggered disk thickening. II. Results and interpretations.|
We have reported in a previous paper (Paper I, Reshetnikov and Combes,1996A&AS..116..417R) B,V and I band photometric data for a sample of24 edge-on interacting spiral galaxies, together with a control sampleof 7 edge-on isolated galaxies. We discuss here the main result found inthis study: the ratio h/z_0_ of the radial exponential scalelength h tothe constant scaleheight z_0_ is about twice smaller for interactinggalaxies. This is found to be due both to a thickening of the plane, andto a radial stripping or shrinking of the stellar disk. If we believethat any galaxy experienced a tidal interaction in the past, we mustconclude that continuous gas accretion and subsequent star formation canbring back the ratio h/z_0_ to higher values, in a time scale of 1Gyr.
|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.
|Tidally-triggered disk thickening. I. Observations.|
As part of an investigation on what effect galaxy interactions have onthe z-structure of the disks of involved galaxies, we present here newphotometric data in the B, V, I passbands for a sample of 24 interactingsystems and 7 non-interacting galaxies. Isophotes, total magnitudes andcolours of all sample galaxies (67) are determined. Our estimates andthe comparison with the published results show that the accuracy of ourphotometry is about 0.15mag.
|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.
|A near-infrared imaging survey of interacting galaxies - The small angular-size ARP systems|
Near-IR images of a large sample of interacting galaxies selected fromthe Atlas of Peculiar Galaxies by Arp (1966) have been obtained.Approximately 180 systems have been imaged in at least two, and usuallythree of the standard JHK bands. The survey and the observing and datareduction procedures, are described, and contour plots and aperturephotometry are presented. Future papers will analyze the imaging data bygroupings based on interaction type, stage, and progenitors. The goalsof the analysis are to explore the relationships between galaxyinteractions, activity, and morphology by studying the structure of thenear-IR luminosity distribution, where extinction effects are muchreduced relative to the optical and the major stellar mass component ofgalaxies dominates the observed light.
|Atlas of Peculiar Galaxies|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1966ApJS...14....1A&db_key=AST
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