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|The scaling relations of early-type galaxies in clusters. I. Surface photometry in seven nearby clusters|
This is the first paper of a series investigating the scaling relationsof early-type galaxies in clusters. Here we illustrate the multi-bandimagery and the image reduction and calibration procedures relative tothe whole sample of 22 clusters at 0.05 <~ z <~ 0.25. We alsopresent detailed surface photometry of 312 early-type galaxies in 7clusters in the first redshift bin, z ≈0.025-0.075. We give for eachgalaxy the complete set of luminosity and geometrical profiles, and anumber of global, photometric and morphological parameters. They havebeen evaluated taking into account the effects of seeing. Internalconsistency checks and comparisons with data in the literature confirmthe quality of our analysis. These data, together with the spectroscopicones presented in the second paper of the series, will provide the localcalibration of the scaling relations. Tables 6, 7a-7g, the colour printsof Figs. 12a-12g AND Figs. 13a-13g are only available in electronic format http://www.edpsciences.com. The complete set of profiles is availableupon request from the authors. Tables 7a-7g are also available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(188.8.131.52) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/387/26
|The peculiar motions of early-type galaxies in two distant regions - VII. Peculiar velocities and bulk motions|
We present peculiar velocities for 85 clusters of galaxies in two largevolumes at distances between 6000 and 15000kms-1 in thedirections of Hercules-Corona Borealis and Perseus-Pisces-Cetus (theEFAR sample). These velocities are based on Fundamental Plane (FP)distance estimates for early-type galaxies in each cluster. We fit theFP using a maximum likelihood algorithm which accounts for bothselection effects and measurement errors, and yields FP parameters withsmaller bias and variance than other fitting procedures. We obtain abest-fitting FP with coefficients consistent with the best existingdeterminations. We measure the bulk motions of the sample volumes usingthe 50 clusters with the best-determined peculiar velocities. We findthat the bulk motions in both regions are small, and consistent withzero at about the 5per cent level. The EFAR results are in agreementwith the small bulk motions found by Dale et al. on similar scales, butare inconsistent with pure dipole motions having the large amplitudesfound by Lauer & Postman and Hudson et al. The alignment of the EFARsample with the Lauer & Postman dipole produces a strong rejectionof a large-amplitude bulk motion in that direction, but the rejection ofthe Hudson et al. result is less certain because their dipole lies at alarge angle to the main axis of the EFAR sample. We employ a windowfunction covariance analysis to make a detailed comparison of the EFARpeculiar velocities with the predictions of standard cosmologicalmodels. We find that the bulk motion of our sample is consistent withmost cosmological models that approximately reproduce the shape andnormalization of the observed galaxy power spectrum. We conclude thatexisting measurements of large-scale bulk motions provide no significantevidence against standard models for the formation of structure.
|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.
|A catalogue of spatially resolved kinematics of galaxies: Bibliography|
We present a catalogue of galaxies for which spatially resolved data ontheir internal kinematics have been published; there is no a priorirestriction regarding their morphological type. The catalogue lists thereferences to the articles where the data are published, as well as acoded description of these data: observed emission or absorption lines,velocity or velocity dispersion, radial profile or 2D field, positionangle. Tables 1, 2, and 3 are proposed in electronic form only, and areavailable from the CDS, via anonymous ftp to cdsarc.u-strasbg.fr (to184.108.40.206) or via http://cdsweb.u-strasbg.fr/Abstract.html
|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.
|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.
|The fundamental plane of early-type galaxies: stellar populations and mass-to-light ratio.|
We analyse the residuals to the fundamental plane (FP) of ellipticalgalaxies as a function of stellar-population indicators; these are basedon the line-strength parameter Mg_2_ and on UBVRI broad-band colors, andare partly derived from new observations. The effect of the stellarpopulations accounts for approximately half the observed variation ofthe mass-to-light ratio responsible for the FP tilt. The residual tiltcan be explained by the contribution of two additional effects: thedependence of the rotational support, and possibly that of the spatialstructure, on the luminosity. We conclude to a constancy of thedynamical-to-stellar mass ratio. This probably extends to globularclusters as well, but the dominant factor would be here the luminositydependence of the structure rather than that of the stellar population.This result also implies a constancy of the fraction of dark matter overall the scalelength covered by stellar systems. Our compilation ofinternal stellar kinematics of galaxies is appended.
|Brightest cluster galaxies as standard candles|
We investigate the use of brightest cluster galaxies (BCGs) as standardcandles for measuring galaxy peculiar velocities on large scales. Wehave obtained precise large-format CCD surface photometry and redshiftsfor an all-sky, volume-limited (z less than or = 0.05) sample of 199BCG. We reinvestigate the Hoessel (1980) relationship between the metricluminosity, Lm, within the central 10 kpc/h of the BCGs andthe logarithmic slope of the surface brightness profile, alpha. TheLm-alpha relationship reduces the cosmic scatter inLm from 0.327 mag to 0.244 mag, yielding a typical distanceaccuracy of 17% per BCG. Residuals about the Lm-alpharelationship are independent of BCG luminosity, BCG B - Rccolor, BCG location within the host cluster, and richness of the hostcluster. The metric luminosity is independent of cluster richness evenbefore correcting for its dependence on alpha, which provides furtherevidence for the unique nature of the BCG luminosity function. Indeed,the BCG luminosity function, both before and after application of thealpha-correction, is consistent with a single Gaussian distribution.Half the BCGs in the sample show some evidence of small color gradientsas a function of radius within their central 50 kpc/h regions but withalmost equal numbers becoming redder as becoming bluer. However, withthe central 10 kpc/h the colors are remarkably constant -- the mean B -Rc color is 1.51 with a dispersion of only 0.06 mag. Thenarrow photometric and color distributions of the BCGs, the lack of'second-parameter' effects, as well as the unique rich clusterenvironment of BCGs, argue that BCGs are the most homogeneous distanceindicators presently available for large-scale structure research.
|The complex structure of Abell 2151 (Hercules)|
We analyzed the space distribution of 117 galaxies in an area of 0.9 degradius centered on NGC 6045 in the Hercules cluster in the velocityrange 9000 to 14,000 km/s. By taking advantage of 74 morphologies basedon CCD images, we succeed in isolating a cluster of galaxies with anaverage velocity of 11,467 km/s located to the NE of the assumedcentroid of A2151, where early and late type galaxies share the samedynamical properties. The implications of this result for the nature andidentification of the x-ray source is briefly discussed.
|Sensitive limits on the molecular gas content of cluster cooling flows|
We have searched for molecular gas toward six cluster cooling flows inthe CO(2-1) line using the James Clerk Maxwell Telescope. The sampleincludes clusters with estimated total cooling rates ofm-dotCF approximately 10-600 solar mass/yr, at redshiftsbetween z approximately 0.01-0.06. None were detected either in emissionor absorption. Our molecular mass limits in the inner approximately 25kpc are typically MH2 less than or approximately equal to 4 x109 solar mass. Our limit for the nearest cluster, A 1060, isan order of magnitude lower. In the aggregate, these are the mostsensitive limits available for cluster cooling flows. Using modelspectra we find that molecular cloud populations as massive as few1010 solar mass with velocity dispersions less than orapproximately equal to 500 km/s are usually excluded, unless thematerial is colder and/or and has a significantly lower metal abundancecompared to average Galactic clouds. If the steady state cooling flowmodel is correct, the cooling material must be converted efficiently toa non-gaseous state on a timescale of approximately107-108 yr, or the putative cold clouds must beaccelerated to a velocity dispersion greater than or approximately equalto 700 km/s on a similar timescale. Future observations with broaderbandwidths should yield improved limits. Failure to detect CO at levelssignificantly lower than these may be difficult to reconcile withstandard cooling flow models.
|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.
|Dark matter and dynamics in the Hercules Cluster (A2151)|
New 21-cm observations of faint spiral galaxies in the Hercules cluster(A2151) are presented in order to investigate the dynamics throughoutthe cluster core, out to a projected radius of 1.8/h Mpc. The globaldynamical mass of Hercules is calculated using the virial theorem andthe projected mass estimator. These masses lie in the range 3-9 x 10 exp14 solar masses. The importance of subclustering in A2151 by eye isexamined via the statistical test of Dressler & Shectman (1988), andby considering the effects of the detected substructure on the dynamicalmass determination. The clumpy distribution is interpreted as a signthat the galaxies in the cluster have not reached dynamical equilibriumin the gravitational potential.
|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.
|The stellar kinematics of elliptical galaxies|
Observations on stellar kinematics of elliptical galaxies are discussed.Progress that has been made over the last four years in the study of theFaber-Jackson relation and the rotation of early-type galaxies as afunction of luminosity is reviewed. Recent studies on the figures ofelliptical galaxies and on whether ellipticals have constantmass-to-light ratio as a function of radius are examined.
|The structure of brightest cluster members. II - Mergers|
Surface photometry of 342 bright elliptical galaxies in 103 clusters isanalyzed for evidence of mergers. Structural differences betweenbrightest cluster members (BCMs) and normal ellipticals can besummarized as having enlarged characteristic radii and shallow profileslopes (beta greater than -1.7). Profile morphology criteria for theelliptical types gE, D, and cD are outlined. Comparison of observationswith numerical simulations of mergers strongly suggests a past historyof dynamical growth for BCMs. Weak correlations of global clusterproperties to BCMs supports the hypothesis proposed by Merritt (1984)that mergers are important in early subgroups before virialization andformation of a cluster identity.
|A catalog of galaxies in Hercules from the Palomar Sky Survey and the Minnesota Automated Plate Scanner|
The development of galaxies catalogs from the Palomar Sky Survey usingthe Minnesota Automated Plate Scanner (APS) is examined. The design andoperation of APS are described. The algorithm used to distinguish starsfrom galaxies is discussed, and the completeness and confusion of thealgorithm as a function of magnitude are estimated. The quality of thephotometric calibration for galaxy magnitudes and surface-brightnessthresholds is evaluated. The relation between the distribution of colorsand morphological types is studied. The luminosity functions forHercules galaxies are calculated and presented. The catalog generatedusing the APS is 80 percent complete; photometry good to 0.23 mag rms ispossible; and J-F colors are good to 0.17 mag rms.
|The distance to the Hercules supercluster. I - Basic data for 220 galaxies in CGCG field 108.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1986ApJS...62..255B&db_key=AST
|The evolution of galaxies in clusters. IV - Photometry of 10 low-redshift clusters|
Colors and magnitudes, obtained from Palomar 48 inch (1.2 m) Schmidtplates in the J and F bands, and morphological types are presented forgalaxies in the cores of 10 nearby clusters of galaxies. In the typicalcluster, the sample includes all galaxies within a radius of 1.5 Mpc(assuming H(0) = 50 km/s/Mpc) of the cluster center and brighter than J= 17.5.The accuracy of the photometry varies with cluster, but mostmagnitudes are accurate to 0.10 mag, and typical errors in the colorsare of the same order. As expected, the colors of the elliptical and S0galaxies show a narrow dispersion about a mean color which decreaseswith magnitude. However, the colors of the spiral galaxies are notentirely as expected, having a smaller dispersion than would have beenpredicted from their morphological types.
|Photoelectric Observations of Interacting and Compact Galaxies|
|The Evolution of Galaxies in Clusters|
|A comparison of distance scales for early-type galaxies|
The distance scales of elliptical and lenticular galaxies areintercompared, based on the velocity dispersion indicator derived from arevised Faber-Jackson relation. The scales are found to be in nearperfect agreement with scales derived from the luminosity index and fromthe 21 cm line width indicator. The scales are also in excellentagreement with the distance scale derived by Michard (1979). Additionsare offered for the general catalog of 424 early-type galaxies, and aseries of reduction equations is presented which reduces the externalerrors in the distance moduli.
|Corrections to the Reference Catalogue of Bright Galaxies (Third List)|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972PASP...84..462C&db_key=AST
|Notes on the Hercules Galaxy Cluster|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971PASP...83..320C&db_key=AST
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