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The spectral energy distributions of the revised 200-mJy sample
We address the question of why low-luminosity radio sources withsimilar flat radio spectra show a range of optical activity. Theinvestigation is based on the spectral energy distributions (SEDs) ofobjects from the 200-mJy sample. We gathered new data from the VLA at 43GHz, from SCUBA in the JCMT at 2000, 1350 and 850 μm, and from theISOPHOT instrument on ISO at 170, 90, 60 and 25 μm. There isconsiderable diversity amongst the SEDs of the objects: there areobjects with steep broad-band spectra between centimetre and millimetrebands (14 per cent of the sample); there are those with flat broad-bandspectra over most of the spectral range (48 per cent of the sample); andthere are those which show pronounced submillimetre/infrared excesses(27 per cent of the sample). Some objects of the first group havetwo-sided radio morphology, indicating that their parsec-scale emissionis not dominated by beamed jet emission. Amongst the objects that havesmooth broad-band spectra from the radio to the infrared, there arepassive elliptical galaxies as well as the expected BL Lacertae objects.The most pronounced submillimetre/infrared excesses are shown by thebroad-emission-line objects.
| VLBA polarization observations of BL Lac objects and passive elliptical galaxies
We present Very Long Baseline Array (VLBA) 5-GHz polarimetricobservations of 23 BL Lacertae (BL Lac) objects and radio galaxiesselected from the 200-mJy sample. BL Lac objects have core polarizationvalues lower than those found in previous samples. The magnetic fieldgeometry in the jets is not unique: both parallel and perpendiculargeometries are observed, even in the same sources. The parsec-scalemorphology of radio galaxies is clearly divided in two classes:one-sided core-jet sources, which show polarized emission in the coreand/or jet, and two-sided symmetric objects which are not polarized. Wediscuss and compare the parsec-scale polarization properties of theradio cores and jets for the BL Lac objects and the radio galaxies inrelation to their parsec-scale morphology and high-frequency integratedspectral index.
| Automated optical identification of a large complete northern hemisphere sample of flat-spectrum radio sources with [formmu1]S6 cm>200 mJy
This paper describes the automated optical APM identification of radiosources from the Jodrell Bank-VLA Astrometric Survey (JVAS), as used forthe search for distant radio-loud quasars. Since JVAS was not intendedto be complete, a new complete sample, JVAS++, has been constructed withselection criteria similar to those of JVAS (S5GHz>200mJy,α1.4-5GHz>-0.5), and with the use of the moreaccurate GB6 and NVSS surveys. Comparison between this sample and JVASindicates that the completeness and reliability of the JVAS survey are~90 and ~70 per cent respectively. The complete sample has been used toinvestigate possible relations between optical and radio properties offlat-spectrum radio sources. From the 915 sources in the sample, 756have an optical APM identification on a red (e) and/or blue (o) plate,resulting in an identification fraction of 83 per cent with acompleteness and reliability of 98 and 99 per cent respectively. About20 per cent are optically identified with extended APM objects on thered plates, e.g., galaxies. However, the distinction between galaxiesand quasars can not be made properly near the magnitude limit of thePOSS-I plates. The identification fraction appears to decrease from>90 per cent for sources with a 5-GHz flux density of >1Jy, to<80 per cent for sources at 0.2Jy. The identification fraction, inparticular that for unresolved quasars, is found to be lower for sourceswith steeper radio spectra. In agreement with previous studies, we findthat the quasars at low radio flux density levels also tend to havefainter optical magnitudes, although there is a large spread. Inaddition, objects with a steep radio-to-optical spectral index are foundto be mainly highly polarized quasars, supporting the idea that in theseobjects the polarized synchrotron component is more prominent. It isshown that the large spread in radio-to-optical spectral index ispossibly caused by source-to-source variations in the Doppler boostingof the synchrotron component.
| 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.
| A new list of extra-galactic radio jets
A catalogue of extra-galactic jets is very useful both in observationaland theoretical studies of active galaxies. With the use of new powerfulradio instruments, the detailed structures of very compact or weak radiosources are investigated observationally and many new radio jets aredetected. In this paper, we give a list of 661 radio sources withdetected radio jets known to us prior to the end of December 2000. Allreferences are collected for the observations of jets in radio, IR,optical, UV and X-ray wave-bands. Table 1 and references to Table 1 areonly available in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/381/757
| The Radio Galaxy Populations of Nearby Northern Abell Clusters
We report on the use of the NRAO VLA Sky Survey (NVSS) to identify radiogalaxies in 18 nearby Abell clusters. The listings extend from the coresof the clusters out to radii of 3 h-175 Mpc, whichcorresponds to 1.5 Abell radii and approximately 4 orders of magnitudein galaxy density. To create a truly useful catalog, we have collectedoptical spectra for nearly all of the galaxies lacking public velocitymeasurements. Consequently, we are able to discriminate between thoseradio galaxies seen in projection on the cluster and those that are inactuality cluster members. The resulting catalog consists of 329 clusterradio galaxies plus 138 galaxies deemed foreground or backgroundobjects, and new velocity measurements are reported for 273 of theseradio galaxies. The motivation for the catalog is the study of galaxyevolution in the cluster environment. The radio luminosity function is apowerful tool in the identification of active galaxies, as it isdominated by star-forming galaxies at intermediate luminosities andactive galactic nuclei (AGNs) at higher luminosities. The flux limit ofthe NVSS allows us to identify AGNs and star-forming galaxies down tostar formation rates less than 1 Msolar yr-1. Thissensitivity, coupled with the all-sky nature of the NVSS, allows us toproduce a catalog of considerable depth and breadth. In addition tothese data, we report detected infrared fluxes and upper limits obtainedfrom IRAS data. It is hoped that this database will prove useful in anumber of potential studies of the effect of environment on galaxyevolution. Based in part on observations obtained with the Apache PointObservatory 3.5 m telescope, which is owned and operated by theAstrophysical Research Consortium (ARC).
| Structure of the Clusters of Galaxies A 2634, A 1983, and DC 0428-53
The hierarchical and dynamical structure of three clusters of galaxies,A 2634, A 1983, and DC 0428-53, is investigated. Based on their example,we can say that the central cD galaxies play the leading role inclusters, affecting the course of their evolution. Radio and x-raygalaxies are not always part of the substructure. The morphologicalcomposition of various hierarchical subgroups depends on the stage ofevolution. Clusters have a tendency to be oriented in the directiontoward the nearest neighbor.
| Multicolor Photometry of the Galaxies in the Central Region of Abell 2634
An optical photometric observation with theBeijing-Arizona-Taipei-Connecticut multicolor system is carried out forthe central region of the nearby cluster of galaxies Abell 2634. Fromthe 2K×2K CCD images with 14 filters, which cover a range ofwavelength from 3600 to 10000 Å, 5572 sources are detected down toV~20 mag in a field of 56'×56' centered onthis regular cluster of galaxies. As a result, we achieved the spectralenergy distributions (SEDs) of all sources detected. There are 178previously known galaxies included in our observations, 147 of whichhave known radial velocities in the literature. After excluding theforeground and background galaxies, a sample of 124 known members isformed for an investigation of the SED properties. The comparison ofobserved SEDs of the early-type member galaxies with the template SEDsdemonstrates the accuracy and reliability of our photometricmeasurements. Based on the knowledge of SED properties of membergalaxies, we performed the selection of faint galaxies belonging toAbell 2634. It is well shown that the color-color diagrams are powerfulin the star-galaxy separation. As a result, 359 faint galaxies areselected by their color features. The technique of photometric redshiftand color-magnitude correlation for the early-type galaxies are appliedfor these faint galaxies, and a list of 74 faint member galaxies isachieved. On the basis of the newly generated sample of member galaxies,the spatial distribution and color-magnitude relation of the galaxies inthe core region of Abell 2634 are discussed. There exists a tendencythat the color index dispersion of the early-type members is larger forthe outer region, which might reflect some clues about the environmentaleffect on the evolution of galaxies in a cluster.
| The Arizona-New Mexico Spectroscopic Survey of Galaxies. I. Data for the Western End of the Perseus Supercluster
We present new optical spectroscopic data for 347 galaxies in the regionof the Perseus supercluster. The new data were obtained using theSteward Observatory 2.3 m telescope and cover the whole optical window.Included are redshifts (for 345 objects), absorption-line equivalentwidths, a continuum index measuring the 4000 Å break, andemission-line flux ratios. After 11 objects are rejected for being toofaint and redshifts for 26 objects are added from the literature, wearrive at a complete sample of 361 galaxies. The distribution ofredshifts for the whole sample is examined, and we show the relationshipof the continuum index to morphology.
| Flat radio-spectrum galaxies and BL Lacs. I. Core properties
This paper concerns the relationship of BL Lacs and flat-spectrum weakemission-line galaxies. We compare the weak emission-line galaxies andthe BL Lacs in a sample of 57 flat-spectrum objects (March{ãet al. 1996), using high-frequency radio and non-thermal optical fluxdensities, spectral indices and polarization properties. We considerwhether objects which are not `traditional' BL Lacs - due to theirlarger emission line strengths, and larger Ca II spectral breaks - aresimply starlight diluted BL Lacs. Their broad-band spectral propertiesare consistent with this interpretation, but their radio polarizationmay indicate more subtle effects. Comparison of the weak emission-linegalaxies and the BL Lacs shows that, on average, the former have steeperspectra between 8 and 43 GHz, and are less polarized at 8.4 GHz. This isconsistent with many of the weak-lined objects being at larger angles tothe line of sight than the BL Lacs. In addition to this population, weindicate a number of the weak emission-line galaxies which may be`hidden BL Lacs': relativistically boosted objects very close to theline of sight with an apparently weak AGN.
| Stellar population of ellipticals in different environments: near-infrared spectroscopic observations
Near-infrared spectra of 50 elliptical galaxies in the Pisces, Abell2199 and 2634 clusters, and in the general field, have been obtained.The strength of the CO (2.3-mu m) absorption feature in these galaxiesis used to explore the presence of an intermediate-age population (e.g.asymptotic giant branch stars) in ellipticals in different environments.We find that the strongest evidence for such a population comes fromellipticals in groups of a few members, which we interpret as the resultof recent minor merging of these galaxies with later-type galaxies.Field galaxies from very isolated environments, on the other hand, showno evidence for young or intermediate-age stars as revealed by Hβand CO absorptions, and appear to form a very uniform, old populationwith very little scatter in metallicity and star formation history.
| The peculiar motions of early-type galaxies in two distant regions - II. The spectroscopic data
We present the spectroscopic data for the galaxies studied in the EFARproject, which is designed to measure the properties and peculiarmotions of early-type galaxies in two distant regions. We have obtained1319 spectra of 714 early-type galaxies over 33 observing runs on 10different telescopes. We describe the observations and data reductionsused to measure redshifts, velocity dispersions and the Mgb and Mg_2Lick linestrength indices. Detailed simulations and intercomparison ofthe large number of repeat observations lead to reliable error estimatesfor all quantities. The measurements from different observing runs arecalibrated to a common zero-point or scale before being combined,yielding a total of 706 redshifts, 676 velocity dispersions, 676 Mgblinestrengths and 582 Mg_2 linestrengths. The median estimated errors inthe combined measurements are Delta cz=20 km s^-1, Delta sigma sigma=9.1 per cent, Delta Mgb Mgb=7.2 per cent and Delta Mg_2=0.015 mag.Comparison of our measurements with published data sets shows nosystematic errors in the redshifts or velocity dispersions, and onlysmall zero-point corrections to bring our linestrengths on to thestandard Lick system. We have assigned galaxies to physical clusters byexamining the line-of-sight velocity distributions based on EFAR andZCAT redshifts, together with the projected distributions on the sky. Wederive mean redshifts and velocity dispersions for these clusters, whichwill be used in estimating distances and peculiar velocities and to testfor trends in the galaxy population with cluster mass. The spectroscopicparameters presented here for 706 galaxies combine high-quality data,uniform reduction and measurement procedures, and detailed erroranalysis. They form the largest single set of velocity dispersions andlinestrengths for early-type galaxies published to date.
| Arcsecond Positions of UGC Galaxies
We present accurate B1950 and J2000 positions for all confirmed galaxiesin the Uppsala General Catalog (UGC). The positions were measuredvisually from Digitized Sky Survey images with rms uncertaintiesσ<=[(1.2")2+(θ/100)2]1/2,where θ is the major-axis diameter. We compared each galaxymeasured with the original UGC description to ensure high reliability.The full position list is available in the electronic version only.
| Interferometer phase calibration sources - III. The regions +20<=delta_B1950<=+35 deg and +75<=delta_B1950<=+90 deg
We present a catalogue of 540 compact radio sources in the declinationranges +20<=delta_B1950<=+35 deg and +75<=delta_B1950<=+90deg, the positions of which have been measured to an rms accuracy ofabout 55 mas with the Very Large Array (VLA). These sources areprimarily intended for use as phase calibration sources for MERLIN.However, they will also be suitable as phase calibrators for the VLA andcan be considered as candidate phase calibrators for very long baselineinterferometry (VLBI) networks.
| Groups of galaxies. III. Some empirical characteristics.
Not Available
| The Universality of the Fundamental Plane of E and S0 Galaxies: Spectroscopic Data
We present central velocity dispersion measurements for 325 early-typegalaxies in eight clusters and groups of galaxies, including newobservations for 212 galaxies. The clusters and groups are the A262,A1367, Coma (A1656), A2634, Cancer, and Pegasus Clusters and the NGC 383and NGC 507 Groups. The new measurements were derived frommedium-dispersion spectra that cover 600 Å centered on the Mg I btriplet at lambda ~ 5175 Å. Velocity dispersions were measuredusing the Tonry & Davis cross-correlation method, with a typicalaccuracy of 6%. A detailed comparison with other data sources is made.
| The Universality of the Fundamental Plane of E and S0 Galaxies: Sample Definition and I-Band Photometric Data
As part of a project to compare the fundamental plane and Tully-Fisherdistance scales, we present here I-band CCD photometry for 636early-type galaxies in eight clusters and groups of galaxies. These arethe A262, A1367, Coma (A1656), A2634, Cancer and Pegasus Clusters, andthe NGC 383 and NGC 507 Groups. Sample selection, cluster properties,and cluster membership assignment criteria are discussed. We presentphotometric parameters that are used in the fundamental plane relation,the effective radius r_e, and the effective surface brightness mu_e, asderived from a r^1/4 fit to the observed radial photometric profile ofeach galaxy. A comparison with similar data found in the literature forthe Coma Cluster shows that large systematic uncertainties can beintroduced in the measurement of r_e and mu_e by the particular methodused to derive those parameters. However, the particular combination ofthese two parameters that enters in the fundamental plane relation is aquantity that can be measured with high accuracy.
| Galaxy Alignments in the Pisces-Perseus Supercluster Revisited
A search for preferential galaxy alignments in the Pisces-PerseusSupercluster (PPS) is made using the Minnesota Automated Plate ScannerPisces-Perseus Survey (MAPS-PP). The MAPS-PP is a catalog of ~1400galaxies with a (roughly) isophotal diameter greater than 30"constructed from digitized scans of the blue and red plates of thePalomar Observatory Sky Survey covering the PPS. This is the largestsample of galaxies applied to a search of galaxy alignments in thissupercluster, and it has been used in combination with previouslypublished redshifts to construct the deepest PPS galaxy luminosityfunction to date. While previous studies have relied extensively oncatalogs with visually estimated parameters for both sample selectionand determination of galaxy orientation, the MAPS-PP uses selectioncriteria and measurements that are entirely machine and computer based.Therefore, it is not susceptible to some of the biases, such as thediameter inclination effect, known to exist in some other galaxycatalogs. The presence of anisotropic galaxy distributions is determinedby use of the Kuiper statistic, a robust alternative to the chi^2statistic more traditionally used in these studies. Three statisticallysignificant anisotropic distributions are observed. The reddest galaxiesare observed to be oriented preferentially perpendicular to the locallarge-scale structure. The bluest galaxies near the supercluster planeare observed to have an anisotropic position angle distribution.Finally, a weak trend for the median position angle of color-selectedgalaxy subsamples to ``twist'' with increasing distance from the PPSplane is observed. These position angle distribution anisotropies areweak and are not consistent with any single primordial or modern-eragalaxy alignment mechanism, although a mixture of such mechanisms is notruled out.
| A catalogue of Mg_2 indices of galaxies and globular clusters
We present a catalogue of published absorption-line Mg_2 indices ofgalaxies and globular clusters. The catalogue is maintained up-to-datein the HYPERCAT database. The measurements are listed together with thereferences to the articles where the data were published. A codeddescription of the observations is provided. The catalogue gathers 3541measurements for 1491 objects (galaxies or globular clusters) from 55datasets. Compiled raw data for 1060 galaxies are zero-point correctedand transformed to a homogeneous system. Tables 1, 3, and 4 areavailable in electronic form only at the CDS, Strasbourg, via anonymousftp 130.79.128.5. Table 2 is available both in text and electronic form.
| Total magnitude, radius, colour indices, colour gradients and photometric type of galaxies
We present a catalogue of aperture photometry of galaxies, in UBVRI,assembled from three different origins: (i) an update of the catalogueof Buta et al. (1995) (ii) published photometric profiles and (iii)aperture photometry performed on CCD images. We explored different setsof growth curves to fit these data: (i) The Sersic law, (ii) The net ofgrowth curves used for the preparation of the RC3 and (iii) A linearinterpolation between the de Vaucouleurs (r(1/4) ) and exponential laws.Finally we adopted the latter solution. Fitting these growth curves, wederive (1) the total magnitude, (2) the effective radius, (3) the colourindices and (4) gradients and (5) the photometric type of 5169 galaxies.The photometric type is defined to statistically match the revisedmorphologic type and parametrizes the shape of the growth curve. It iscoded from -9, for very concentrated galaxies, to +10, for diffusegalaxies. Based in part on observations collected at the Haute-ProvenceObservatory.
| The peculiar motions of early-type galaxies in two distant regions. III - The photometric data
We present R-band CCD photometry for 776 galaxies observed in the EFARproject. The photometry is compared with photoelectric data, showingthat a common zero-point good to better than 1 per cent and a precisionof 0.03 mag per zero-point have been achieved. We give the circularlyaveraged surface brightness profiles and the photometric parameters ofthe 762 program galaxies, D(n) diameters, half-luminosity radii, totalmagnitudes, and average effective surface brightnesses. More than 80percent of the profiles have a global S/N ratio larger than 300. Theextrapolation needed to derive total magnitudes is less than 10 percentfor 80 percent of the fits. More than 80 percent of the galaxies havemean effective surface brightness larger than the observed skybrightness. In 90 percent of the profiles the estimate of thecontamination of the sky by the galaxy light is less than 1 percent. Wederive total magnitudes and half-luminosity radii to better than 0.15mag and 25 percent, respectively, for 90 percent of our sample. Incontrast, external comparisons show that data in the literature can bestrongly affected by systematic errors due to large extrapolations,small radial range, sky subtraction errors, seeing effects, and the useof a simple R exp 1/4 fit. The resulting errors can easily amount tomore than 0.5 mag in the total magnitudes and 50 percent in thehalf-luminosity radii.
| Abell 2199 and Abell 2634 revisited
Previous D_n-sigma work found surprisingly large negative peculiarvelocities for Abell 2199 and Abell 2634. In order to assess theseresults independently we have made new spectroscopic and photometricobservations. We report 141 new redshift, velocity dispersion (sigma)and Mg_2 index measurements, and photometry for 79 early-type galaxies.Special attention has been paid to linking the new sigma measurements onto a standard system that minimizes systematic errors. While the Abell2199 sigma measurements are in good agreement with our previouslyreported FLEX values, for Abell 2634 galaxies the new sigmas aresystematically lower. The FLEX measurements for some Abell 2634 galaxiesappear to have been erroneous due to a smearing problem with the CCDdetector. The new photometric data are in excellent agreement withpreviously reported values. We also present a new compilation of datafor 72 early-type Coma cluster galaxies. Assuming that the Coma clusterlies at rest with respect to the cosmic microwave background frame, wederive peculiar velocities of -160+/-380 and -670+/-490 km s^-1 forAbell 2199 and Abell 2634 respectively. We estimate that the likelysystematic errors on these measurements are less than 200kms^-1. Thederived peculiar velocities are considerably less than previousestimates and are not significantly different from zero.
| The Relative Distance Between the Clusters of Galaxies A2634 and Coma
The Tully-Fisher (TF) and Fundamental Plane (FP) relations are used toobtain two independent estimates of the relative distance between theclusters A2634 and Coma. Previously published studies of A2634 showed alarge discrepancy between the distance estimates obtained with the TFand the \dns\ relations, questioning the reliability ofredshift-independent distances obtained using these relations. Becauseof the importance of this issue, we have obtained new distance estimatesfor A2634, based on much larger samples than previously used, andselected according to rigorous membership criteria. New I band CCDphotometry for 175 galaxies, new 21 cm observations of 11 galaxies, andnew velocity dispersion measurements for 62 galaxies are used togetherwith previously published data in building these samples. As part of alarger project to compare the TF and FP distance-scales, we haveobtained a new FP template using for the first time I band photometry.The template is derived using a sample of 109 E and S0 galaxies that aremembers of the Coma cluster. Its parameters are in very good agreementwith recent determinations of the FP obtained at shorter wavelengths.The uncertainty with which the FP can provide peculiar velocityestimates for single galaxies is =~ 0.43 mag in the distance modulus, or20% of the distance. This uncertainty is slightly larger than thetypical uncertainty that characterizes TF estimates. However thisdisadvantage is partly compensated by the fact that the sampleincompleteness bias has a less severe effect on FP cluster distanceestimates than it has on the corresponding TF distance estimates. Also,cluster membership is more readily established for early-type objectsthan for spirals. After the appropriate corrections for sampleincompleteness have been taken into account, we find the TF and FPdistance estimates to be in good agreement, both indicating that A2634has a negligibly small peculiar velocity with respect to the CosmicMicrowave Background reference frame. Because of the high accuracy withwhich the two distance estimates have been obtained, their agreementstrongly supports the universality of the TF and FP relations, andtherefore their reliability for the estimate of redshift-independentdistances.
| Optical spectroscopy and polarization of a new sample of optically bright flat radio spectrum sources
A new sample of bright flat radio spectrum sources selected at 8.4 GHzand consisting of objects brighter than V=17 is discussed. The samplewas selected with three purposes in mind: (i) to find low-luminosity BLLacertae (BL Lac) objects with radio luminosities comparable to those ofBL Lacs selected at X-ray frequencies; (ii) to investigate thedifferences between BL Lacs and other flat radio spectrum sources; and(iii) to define a sample of nearby radio-loud objects, the host galaxiesof which are easy to study. Using information on four observationalparameters, radio polarization, optical percentage polarization, breakcontrast and equivalent width of the strongest emission line, we comparethe properties of BL Lacs with those of other types of active galacticnuclei (AGN) found in the sample We find that most of the objects haveweak emission lines although some sources with Seyfert-type spectra werealso found. With only a few exceptions, the two types of sources appearwell separated in their observational properties. Among the objectsstudied we report 10 new BL Lacs and BL Lac candidates, and we define a`complete' sample of bright flat radio spectrum sources that consists ofthose objects with redshift <=0.1.
| The Peculiar Motions of Early-Type Galaxies in Two Distant Regions. I. Cluster and Galaxy Selection
The EFAR project is a study of 736 candidate elliptical galaxies in 84clusters lying in two regions, toward Hercules-Corona Borealis andPerseus-Pisces-Cetus, at distances cz ~ 6000-15,000 km s^-1^. In thispaper (the first of a series), we present an introduction to the EFARproject and describe in detail the selection of the clusters andgalaxies in our sample. Fundamental data for the galaxies and clustersare given, including accurate new positions for each galaxy andredshifts for each cluster. The galaxy selection functions aredetermined by using diameters measured from Schmidt sky survey imagesfor 2185 galaxies in the cluster fields. Future papers in this serieswill present the spectroscopic and photometric observations of thissample, investigate the properties of the fundamental plane forelliptical galaxies, and determine the large- scale peculiar velocityfields in these two regions of the universe.
| 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 spatial distribution, kinematics, and dynamics of the galaxies in the region of Abell 2634 and 2666
A total of 663 galaxies with known redshifts in a 12 deg x 12 deg fieldcentered on A2634, including 211 new measurements, are used to study indetail the structure of the region. In it we find six main galaxyconcentrations: the nearby clusters A2634 and A2666, two groups in thevicinity of A2634, and two distant clusters at approximately 18,000(A2622) and approximately 37,000 km/s seen in projection near the coreof A2634. For A2634, the most richly sampled of those concentrations, weare able to apply strict cluster membership criteria. Two samples - onecontaining 200 galaxies within 2 deg from the cluster center and asecond, magnitude-limited, of 118 galaxies within the central halfdegree - are used to examine the structure, kinematics, dynamics, andmorphological segregation of the cluster. We show that early typegalaxies appear to be a relaxed system, while the spiral populationeschews the center of the cluster and exhibits both a multimodalvelocity distribution and a much larger velocity dispersion that theellipticals. We propose that the spiral galaxies of A2634 represent adynamically young cluster population. For the galaxy component of A2634,we find no evidence of significant substructure in the central regions.We also conclude that the adoption of lenient membership criteria thatignore the dynamical complexity of A2634 are unlikely to be responsiblefor the conflicting results reported on the motion of this cluster withrespect ot the CMB. The kinematical and dynamical analysis is extendedto A2634's close companion, A2666, and the two distant backgroundclusters.
| Surface photometry of low-luminosity radio galaxies
We present the results on the optical morphology and structure of 25low-luminosity radio galaxies. The radial dependence of parameters likethe surface brightness, ellipticity, center, and position angle of theisophotes is presented to study the properties of the galaxies. Resultsfor individual objects are discussed.
| Photoelectric and CCD photometry of E and S0 galaxies
We present BR photoelectric photometry for 352 E and S0 galaxies thatare part of a large survey of the properties and peculiar motions ofgalaxies in distant clusters. Repeat measurements show our internalerrors to be 2-3 percent in B and R and 1-2 percent in B-R. Comparisonsof BR and BVR reductions for 10 galaxies also observed in V show smallsystematic errors due to differences between the spectral energydistributions of stars and galaxies. External comparisons with B-Vcolors in the literature confirm that these colors are good to 1percent. We also describe R-band CCD observations for 95 of the galaxiesand place these on a BR photometric system for photoelectric and CCDphotomerry, with a common zero-point good to better than 1 percent. Wefind the rms precision of both our photoelectric and CCD R magnitudes tobe 2-3 percent for galaxies as faint as R = 15.
| The Dynamics of the Galaxy Cluster Abell 2634
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993ApJ...416...36P&db_key=AST
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