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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.
| Star Formation and Active Galactic Nuclei in the Core of the Shapley Supercluster: A Very Large Array Survey of A3556, A3558, SC 1327-312, SC 1329-313, and A3562
The core of the Shapley supercluster (A3556, A3558, SC 1327-312, SC1329-313, and A3562) is an ideal region in which to study the effects ofcluster mergers on the activity of individual galaxies. This paperpresents the most comprehensive radio continuum investigation of theregion, relying on a 63 pointing mosaic obtained with the Very LargeArray yielding an areal coverage of nearly 7 deg2. The mosaicprovides a typical sensitivity of about 80 μJy at a resolution of16", enabling the detection of galaxies with star formation rates as lowas 1 Msolar yr-1. The radio data are complementedby optical imaging in the B and R bands, producing a catalog of 210radio-detected galaxies with mR<=17.36(MR<=-19). At least 104 of these radio-detected galaxiesare members of the supercluster on the basis of public velocitymeasurements. Across the entire core of the supercluster, there appearsto be a significant deficit of radio galaxies at intermediate opticalmagnitudes (-21>=MR>-22). This deficit is offsetsomewhat by an increase in the frequency with which brighter galaxies(MR<=-22) host radio sources. More dramatic is the highlysignificant increase in the probability for fainter galaxies(-20>=MR>-21) in the vicinity of A3562 and SC 1329-313to be associated with radio emission. The radio and optical data forthese sources strongly suggest that these active galaxies are powered bystar formation. In conjunction with recent X-ray analysis, this isinterpreted as young starbursts related to the recent merger of SC1329-313 with A3562 and the rest of the supercluster.
| FLASH redshift survey - I. Observations and catalogue
The FLAIR Shapley-Hydra (FLASH) redshift survey catalogue consists of4613 galaxies brighter than bJ= 16.7 (corrected for Galacticextinction) over a 700-deg2 region of sky in the generaldirection of the Local Group motion. The survey region is a70°× 10° strip spanning the sky from the ShapleySupercluster to the Hydra cluster, and contains 3141 galaxies withmeasured redshifts. Designed to explore the effect of the galaxyconcentrations in this direction (in particular the Supergalactic planeand the Shapley Supercluster) upon the Local Group motion, the 68 percent completeness allows us to sample the large-scale structure betterthan similar sparsely-sampled surveys. The survey region does notoverlap with the areas covered by ongoing wide-angle (Sloan or 2dF)complete redshift surveys. In this paper, the first in a series, wedescribe the observation and data reduction procedures, the analysis forthe redshift errors and survey completeness, and present the surveydata.
| Two Galaxy Clusters: A3565 and A3560
We report 102 new redshifts and magnitudes for a sample of galaxies toR_F~15.5 mag in a 2.17dx2.17d region centered on the galaxy IC 4296, themost luminous member of the A3565 Cluster. Up to the limiting magnitude,we find 29 cluster members and measure a velocity dispersion ofsigma=228 km s^-1. The estimated total mass for this system is~3.0x10^13 h^-1 M_solar [where h=H_0/(100 km s^-1 Mpc^-1)], and itsdynamical properties are quite typical of poor clusters presenting X-rayemission. We also find that galaxies with absorption lines are moreconcentrated toward the center of the cluster, while systems withemission lines are mainly located in the outer parts. The small velocitydispersion of the cluster, coupled with the known presence of aninteracting pair of galaxies, and the large extent of the brightestcluster galaxy, could indicate that galaxy formation through mergers maystill be underway in this system. The surveyed region also containsgalaxies belonging to the Shapley concentration cluster A3560. Within30' of the cluster center, we detect 32 galaxies, for which we measure avelocity dispersion of 588 km s^-1 and a mass of ~2x10^14 h^-1 M_solar.However, because our sample is restricted to galaxies brighter than M^*,these values should be considered only as rough estimates.
| 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).
| Structure and kinematics of galaxy clusters. I. The redshift catalogue.
An extensive redshift survey has been conducted on a sample of 15 nearby(0.01<~z<~0.05) clusters of galaxies. A total number of 860redshifts were determined by fitting of emission-lines and/orcross-correlation techniques. Of this sample, 735 galaxies are within0.2-0.8Mpc (H_0_=50km/s/Mpc) of the center of clusters. Approximatemorphological types are available for most of the galaxies. A comparisonof the present redshifts with published data allows an extensive erroranalysis. The agreement is excellent with the most modern data, showinga zero point error of 5km/s and an overall consistency of themeasurements and their uncertainties. We estimate our redshifts to havemean random errors around 30km/s. A population analysis of the clusterswill be given in a forthcoming paper.
| Multicolour photometry of the Shapley 8 cluster of galaxies
In a previous paper, we measured 40 redshifts in the core of the richsouthern cluster Shapley 8. We now present photographicb26.75 magnitudes, radii and ellipticities, together with(u-b) and (b-r) colors for 4903 galaxies within a 4.69 square degreefield around this cluster. We have also measured (r-i) colors for asubset of these galaxies around the cluster core. Our sample isessentially complete to b26.75 = 20.85. We discuss thecolor-related properties of the cluster, together with its luminosityfunction and spatial distribution. We find a deficit of blue galaxies inthe cluster core, implying morphological segregation, and also evidencethat the brightest galaxies are less tightly clustered than the rest.There is a clear change of slope at Mb approximately equal to-20.4 in the ultraviolet color-magnitude relations for the E/SOgalaxies. We also show how the color data can be used to isolatehigh-redshift background galaxies. The mass enclosed within the area wehave studied is 4.5 x 1015 Stellar Mass, which appears to betoo low for the Shapley Supercluster to be the explanation of the 'GreatAttractor'.
| The surface photometry catalogue of the ESO-Uppsala galaxies
Not Available
| Static properties of galaxies in the Shapley-Centaurus cluster. I - The catalogue
A catalogue of the positions, sizes, orientations, ellipticities, andmorphological descriptions of 127 galaxies measured in the Southern SkySurvey Field 444 is given. The measurement errors, both internal andexternal, are discussed.
| Redshifts in Klemola 27
Observational data for galaxies in the galaxy cluster Klemola 27gathered over the last few years are presented. These are mostly newredshifts and further, accurate coordinates and morphological types fora large number of 'prominent' galaxies in the ESO/SRC-Survey fields 444and 445. A few preliminary H I radial velocities are also reported. Thedata available for this cluster are briefly discussed.
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