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The scaling relation of early-type galaxies in clusters. II. Spectroscopic data for galaxies in eight nearby clusters
Aims.We present low and intermediate resolution spectroscopic datacollected for 152 early type galaxies in 8 nearby clusters with z ≤0.10. Methods: .We use low resolution data to produce the redshiftand the K-correction for each galaxy, as well as to give their overallspectral energy distribution and some spectral indicators, including the4000 Å break, the Mg2 strength and the NaD equivalent width. Wehave also obtained higher resolution data for early type galaxies inthree of the clusters, to determine their central velocity dispersion. Results: .The effect of the resolution on the measured parametersis discussed. Conclusions: .A new accurate systemic redshift andvelocity dispersion is presented for four of the surveyed clusters, A98,A3125, A3330, and DC2103-39. We have found that the K-correction valuesfor E/S0 bright galaxies in the given nearby clusters are very similar.We also find that the distribution of the line indicators significantlydiffers from cluster to cluster.
| Group, field and isolated early-type galaxies - II. Global trends from nuclear data
We have derived ages, metallicities and enhanced-element ratios[α/Fe] for a sample of 83 early-type galaxies essentially ingroups, the field or isolated objects. The stellar-population propertiesderived for each galaxy correspond to the nuclear re/8aperture extraction. The median age found for Es is 5.8+/-0.6 Gyr andthe average metallicity is +0.37+/-0.03 dex. For S0s, the median age is3.0+/-0.6 Gyr and [Z/H]= 0.53+/-0.04 dex. We compare the distribution ofour galaxies in the Hβ-[MgFe] diagram with Fornax galaxies. Ourelliptical galaxies are 3-4 Gyr younger than Es in the Fornax cluster.We find that the galaxies lie in a plane defined by [Z/H]= 0.99logσ0- 0.46 log(age) - 1.60, or in linear terms Z~σ0× (age) -0.5. More massive (largerσ0) and older galaxies present, on average, large[α/Fe] values, and therefore must have undergone shorterstar-formation time-scales. Comparing group against field/isolatedgalaxies, it is not clear that environment plays an important role indetermining their stellar-population history. In particular, ourisolated galaxies show ages differing by more than 8 Gyr. Finally weexplore our large spectral coverage to derive log(O/H) metallicity fromthe Hα and NIIλ6584 and compare it with model-dependent[Z/H]. We find that the O/H abundances are similar for all galaxies, andwe can interpret it as if most chemical evolution has already finishedin these galaxies.
| Group, field and isolated early-type galaxies - I. Observations and nuclear data
This is the first paper of a series on the investigation of stellarpopulation properties and galaxy evolution of an observationallyhomogeneous sample of early-type galaxies in groups, field and isolatedgalaxies.Here we present high signal-to-noise ratio (S/N) long-slit spectroscopyof 86 nearby elliptical and S0 galaxies. Eight of them are isolated,selected according to a rigorous criterion, which guarantees a genuinelow-density subsample. The present survey has the advantage of coveringa larger wavelength range than normally found in the literature, whichincludes [OIII]λ5007 and Hα, both lines important foremission correction. Among the 86 galaxies with S/N >= 15 (perresolution element, for re/8 central aperture), 57 have theirHβ-index corrected for emission (the average correction is 0.190Åin Hβ) and 42 galaxies reveal [OIII]λ5007 emission,of which 16 also show obvious Hα emission. Most of the galaxies inthe sample do not show obvious signs of disturbances nor tidal featuresin the morphologies, although 11 belong to the Arp catalogue of peculiargalaxies; only three of them (NGC 750, 751 and 3226) seem to be stronglyinteracting. We present the measurement of 25 central line-strengthindices calibrated to the Lick/IDS system. Kinematic information isobtained for the sample. We analyse the line-strength index versusvelocity dispersion relations for our sample of mainly low-densityenvironment galaxies, and compare the slope of the relations withcluster galaxies from the literature. Our main findings are that theindex-σ0 relations presented for low-density regionsare not significantly different from those of cluster E/S0s. The slopeof the index-σ0 relations does not seem to change forearly-type galaxies of different environmental densities, but thescatter of the relations seems larger for group, field and isolatedgalaxies than for cluster galaxies.
| A new catalogue of ISM content of normal galaxies
We have compiled a catalogue of the gas content for a sample of 1916galaxies, considered to be a fair representation of ``normality''. Thedefinition of a ``normal'' galaxy adopted in this work implies that wehave purposely excluded from the catalogue galaxies having distortedmorphology (such as interaction bridges, tails or lopsidedness) and/orany signature of peculiar kinematics (such as polar rings,counterrotating disks or other decoupled components). In contrast, wehave included systems hosting active galactic nuclei (AGN) in thecatalogue. This catalogue revises previous compendia on the ISM contentof galaxies published by \citet{bregman} and \citet{casoli}, andcompiles data available in the literature from several small samples ofgalaxies. Masses for warm dust, atomic and molecular gas, as well asX-ray luminosities have been converted to a uniform distance scale takenfrom the Catalogue of Principal Galaxies (PGC). We have used twodifferent normalization factors to explore the variation of the gascontent along the Hubble sequence: the blue luminosity (LB)and the square of linear diameter (D225). Ourcatalogue significantly improves the statistics of previous referencecatalogues and can be used in future studies to define a template ISMcontent for ``normal'' galaxies along the Hubble sequence. The cataloguecan be accessed on-line and is also available at the Centre desDonnées Stellaires (CDS).The catalogue is available in electronic form athttp://dipastro.pd.astro.it/galletta/ismcat and at the CDS via anonymousftp to\ cdsarc.u-strasbg.fr (130.79.128.5) or via\http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/405/5
| Bar Galaxies and Their Environments
The prints of the Palomar Sky Survey, luminosity classifications, andradial velocities were used to assign all northern Shapley-Ames galaxiesto either (1) field, (2) group, or (3) cluster environments. Thisinformation for 930 galaxies shows no evidence for a dependence of barfrequency on galaxy environment. This suggests that the formation of abar in a disk galaxy is mainly determined by the properties of theparent galaxy, rather than by the characteristics of its environment.
| 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(130.79.188.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/387/26
| The formation of galaxy bulges: Spectrophotometric constraints
We have measured Mg2, Fe 5270 and Fe 5335 spectrophotometricindices (LICK system) in the bulge of 89 galaxies, mostly spirals fromthe Héraudeau (\cite{her96}) sample. The indices are reduced to anull velocity dispersion and normalized to an aperture of 0.2h-1 kpc. The mean errors are 0.009 mag on Mg2, and0.3 Å on the iron indices. These measurements almost double theamount of similar data already available on spiral galaxies. Our dataconfirm the existence of the relation between Mg2, andsigma0, the central stellar velocity dispersion; we find aneven tighter relation between Mg2, andVmrot, the maximum rotational velocity of thegalaxy, deduced from HI observations. For the most massive bulges, thesecorrelations may be interpreted as a mass-metallicity relation. However,the presence of young stellar populations, traced by the detection of[OIII] lambda 5007 Å, emission, provides clear evidence that ageeffects do play a role. Since the contribution of the young populationis anti-correlated to the mass of the galaxy, it continues theMg2, vs. sigma0 , relation toward thelow-sigma0, region and globally increases its slope. We alsopresent evidence for a new positive correlation between Fe indices andsigma0, and for a significant correlation between theline-strength indices and the total or disk luminosity. We propose tomodel the whole sequence of bulges within the folowing framework: bulgesare composed of a primary population formed prior to the disk, duringthe initial collapse, and of a secondary population formed during itsevolution. The whole family of bulges can be classified into threeclasses: (A) the bulges dominated by young populations are generallysmall, have ionized gas, low velocity dispersion and low line strengths;(B) the bulges dominated by the primary population lie along themass-metallicity sequence defined for elliptical galaxies; and (C) thebulges where the secondary population is significant are lessMg-over-abundant than (B)-type bulges and deviate from theMg2, vs. sigma0, relation of elliptical galaxies.Based on observations collected at the Observatoire de Haute-Provence.Table 3 is presented in electronic form only at the CDS. Tables 1 and 2are also available form at the CDS, Strasbourg, via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/366/68
| 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.
| A Test for Large-Scale Systematic Errors in Maps of Galactic Reddening
Accurate maps of Galactic reddening are important for a number ofapplications, such as mapping the peculiar velocity field in the nearbyuniverse. Of particular concern are systematic errors which vary slowlyas a function of position on the sky, as these would induce spuriousbulk flow. We have compared the reddenings of Burstein & Heiles (BH)and those of Schlegel, Finkbeiner, & Davis (SFD) to independentestimates of the reddening, for Galactic latitudes |b|>10^deg. Ourprimary source of Galactic reddening estimates comes from comparing thedifference between the observed B-V colors of early-type galaxies, andthe predicted B-V color determined from the B-V-Mg_2 relation. We havefitted a dipole to the residuals in order to look for large-scalesystematic deviations. There is marginal evidence for a dipolar residualin the comparison between the SFD maps and the observed early-typegalaxy reddenings. If this is due to an error in the SFD maps, then itcan be corrected with a small (13%) multiplicative dipole term. Weargue, however, that this difference is more likely to be due to a small(0.01 mag) systematic error in the measured B-V colors of the early-typegalaxies. This interpretation is supported by a smaller, independentdata set (globular cluster and RR Lyrae stars), which yields a resultinconsistent with the early-type galaxy residual dipole. BH reddeningsare found to have no significant systematic residuals, apart from theknown problem in the region 230^deg
| Central Mg_2 indices for early-type galaxies
We present 210 new measurements of the central absorption line-strength{Mg_2} index for 87 early-type galaxies drawn from the \cite[Prugniel& Simien (1996)]{PS96} sample. 28 galaxies were not observed before.The results are compared to measurements published previously asavailable in HYPERCAT, and rescaled to the Lick system. The meanindividual internal error on these measurements is 0.009m+/-0.003m andthe mean external error is 0.012m+/-0.002m for this series ofmeasurements. Based on observations collected at the Observatoire deHaute-Provence. Tables 1, 3 and 4 are available in electronic form fromthe CDS, Strasbourg (via anonymous ftp to 130.79.128.5). Tables 1 and 3are available from CDS only.
| Bulge-Disk Decomposition of 659 Spiral and Lenticular Galaxy Brightness Profiles
We present one of the largest homogeneous sets of spiral and lenticulargalaxy brightness profile decompositions completed to date. The 659galaxies in our sample have been fitted with a de Vaucouleurs law forthe bulge component and an inner-truncated exponential for the diskcomponent. Of the 659 galaxies in the sample, 620 were successfullyfitted with the chosen fitting functions. The fits are generally welldefined, with more than 90% having rms deviations from the observedprofile of less than 0.35 mag. We find no correlations of fittingquality, as measured by these rms residuals, with either morphologicaltype or inclination. Similarly, the estimated errors of the fittedcoefficients show no significant trends with type or inclination. Thesedecompositions form a useful basis for the study of the lightdistributions of spiral and lenticular galaxies. The object base issufficiently large that well-defined samples of galaxies can be selectedfrom it.
| 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.
| 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 (to130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
| Stellar populations of cluster E and S0 galaxies
Spectral line index data for a sample of 290 E and S0 galaxies are usedto investigate the stellar populations of these galaxies. 250 of thegalaxies are members of 11 nearby clusters (cz_CMB<11500 km s^-1). Westudy how the stellar populations of the galaxies are related to thevelocity dispersions, the masses of the galaxies, and the clusterenvironment. This is done by establishing relations between theseparameters and the line indices Mg_2, and Hβ_G. Thedifference between the slope of the Mg_2-sigma relation and the slope ofthe -sigma relation indicates that the abundance ratio [Mg/Fe]is 0.3-0.4 dex higher for galaxies with velocity dispersions of 250 kms^-1 compared to galaxies with velocity dispersions of 100 km s^-1. Thisis in agreement with previous estimates by Worthey et al. The index is more strongly correlated with the projected cluster surfacedensity, rho_cluster, than with the galactic mass or the velocitydispersion. Earlier we found that the residuals for the Mg_2-sigmarelation depend on the cluster environment. Here we determine how boththe Mg_2 index and the index depend on the velocitydispersion and rho_cluster. Alternative explanations that could create aspurious environment dependence are discussed. No obvious alternativesare found. The environment dependence of the Mg_2-sigma relation issupported by data from Faber et al. The dependence on the environmentimplies that [Mg/Fe] decreases with increasing density, rho_cluster. Thedecrease in [Mg/Fe] is 0.1 dex over 2.5 dex in rho_cluster. We have alsostudied the extent to which the mass-to-light (M/L) ratios of thegalaxies are determined by the stellar populations. The M/L ratios arestrongly correlated with the indices Mg_2 and Hβ_G, while the index is only weakly correlated with the M/L ratio. Based oncurrent stellar population models, we find that it is not yet possibleto derive unique physical parameters (mean age, mean abundances, meanIMF, and fraction of dark matter) from the observables (line indices,velocity dispersion, mass, M/L ratio).
| Kinematical data on early-type galaxies. III.
We present new kinematical data for a sample of 24 early-type galaxies.Rotation curves and velocity-dispersion profiles are determined for 21objects, while the central velocity dispersions are given for the wholesample. This is our third paper in a series devoted to the presentationof kinematical data on elliptical and S0 galaxies, derived fromlong-slit absorption spectroscopy. Based on observations collected atthe Observatoire de Haute-Provence. Tables 2 and 4 are presented inelectronic form only; Tables \ref{tab1} through 4 are available from theCDS, Strasbourg (anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/Abstract.html)
| 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 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.
| Spectroscopy for E and S0 galaxies in nine clusters
Central velocity dispersions, Mg_2 line indices and radial velocitiesfor 220 E and S0 galaxies are derived on the basis of intermediateresolution spectroscopy. Galaxies in the following clusters have beenobserved: Abell 194, Abell 539, Abell 3381, Abell 3574, S639, S753,Doradus, HydraI (Abell 1060) and Grm 15. For 151 of the galaxies, thevelocity dispersion has not previously been measured. 134 of the Mg_2determinations are for galaxies with no previous measurement. Thespectra cover either 500 or 1000A, centred on the magnesium triplet at5177A. The observations were obtained with the Boller & Chivensspectrograph at the ESO 1.5-m telescope and with the OPTOPUS, amulti-object fibre-fed B&C spectrograph, at the ESO 3.6-m telescope.The data are part of our ongoing study of the large-scale motions in theUniverse and the physical background for the Fundamental Plane. TheFourier fitting method was used to derive the velocity dispersions andradial velocities. The velocity dispersions have been corrected for theeffect of the size of the aperture. The correction was established onthe basis of velocity dispersion profiles available in the literature. Acomparison with results from Davies et al. shows that the derivedcentral velocity dispersions have an rms error of 0.036 in logsigma.There is no offset relative to the velocity dispersions from Davies etal. The offset relative to data from Lucey & Carter is-0.017+/-0.011 in logsigma, with our velocity dispersions being thesmallest. The velocity dispersions derived from the B&C and theOPTOPUS observations, as well as the velocity dispersions published byDavies et al., Dressler, Lucey & Carter and Lucey et al., can bebrought on a system consistent within 3 per cent. The Mg_2 line indiceshave been corrected for the size of the apertures, transformed to theLick system, and corrected for the effect of the velocity dispersion.From comparison with data from Davies et al. and from Faber, we findthat the rms error of Mg_2 is 0.013. Comparisons of the radialvelocities with data from the literature show that our determinationsare accurate to within ~=35 km s^-1. The accuracies reached for theseobservations are adequate for the study of the large-scale motions inthe Universe and for investigations of the Fundamental Plane.
| Multicolour CCD surface photometry for E and S0 galaxies in 10 clusters
CCD surface photometry for 232 E and S0 galaxies is presented. Thegalaxies are observed in Gunn r and Johnson B, or Gunn r and g. For 48of the galaxies surface photometry in Johnson U is also presented.Aperture magnitudes in Gunn nu are derived for half of the galaxies.Galaxies in the following clusters have been observed: Abell 194, Abell539, Abell 3381, Abell 3574, Abell S639, Abell S753, HydraI (Abell1060), DC2345-28, Doradus and Grm15. The data are part of our ongoingstudy of the large-scale motions in the Universe and the physicalbackground for the fundamental plane. We use a full model fittingtechnique for analysing the CCD images. This gives radial profiles oflocal surface brightness, colour, ellipticity and position angle. Theresiduals relative to the elliptical isophotes are describedquantitatively by Fourier expansions. Effective radius, mean surfacebrightness and total magnitude are derived by fitting a de Vaucouleursr^¼ growth curve. We have derived a characteristic radius r_nsimilar to the diameter D_n introduced by Dressler et al. The derivationof the effective parameters and of r_n takes the seeing into account. Weconfirm the results by Saglia et al. that the effects of the seeing canbe substantial. Seeing-corrected values of the effective parameters andr_n are also presented for 147 E and S0 galaxies in the Coma cluster.Colours, colour gradients and geometrical parameters are derived. Thephotometry is internally consistent within 0.016 mag. Comparison withthe photoelectric aperture photometry from Burstein et al. shows a meanoffset of 0.010 mag with an rms scatter of 0.034 mag. The globalphotometric parameters are compared with data from Faber et al., Luceyet al. and Lucey & Carter. These comparisons imply that the typicalrms errors are as follows - log r_n:+/-0.015 log r_e:+/-0.045m_T:+/-0.09 mag; _e:+/-0.16 mag. The rms error on thecombination log r_e-0.35_e which enters the fundamental planeis +/-0.020. Also, comparisons with data from Saglia et al. arepresented. The accuracy of the absolute photometry, as well as thederived parameters, makes the data suitable for our investigations ofthe fundamental plane and of the large-scale motions in the Universe.
| A Catalog of Stellar Velocity Dispersions. II. 1994 Update
A catalog of central velocity dispersion measurements is presented,current through 1993 September. The catalog includes 2474 measurementsof 1563 galaxies. A standard set of 86 galaxies is defined, consistingof galaxies with at least three reliable, concordant measurements. It issuggested that future studies observe some of these standard galaxies sothat different studies can be normalized to a consistent system. Allmeasurements are reduced to a normalized system using these standards.
| Total and effective colors of 501 galaxies in the Cousins VRI photometric system
Total color indices (V-R)T, (V-I)T and effectivecolor indices (V-R)e, (V-I)e in the Cousins VRIphotometric system are presented for 501 mostly normal galaxies. Thecolors are computed using a procedure outlined in the Third ReferenceCatalogue of Bright Galaxies (RC3) whereby standard color curvesapproximated by Laplace-Gauss integrals are fitted to observedphotoelectric multiaperture photometry. 11 sources of such photometrywere used for our analysis, each source being assigned an appropriateweight according to a rigorous analysis of residuals of the data fromthe best-fitting standard color curves. Together with the integrated B-Vand U-B colors provided in RC3, our analysis widens the range ofwavelength of homogeneously defined colors of normal galaxies of allHubble types. We present color-color and color-type relations that canbe modeled to understand the star formation history of galaxies.
| Integrated photoelectric magnitudes and color indices of bright galaxies in the Johnson UBV system
The photoelectric total magnitudes and color indices published in theThird Reference Catalogue of Bright Galaxies (RC3) are based on ananalysis of approximately equals 26,000 B, 25,000 B-V, and 17,000 U-Bmultiaperture measurements available up to mid 1987 from nearly 350sources. This paper provides the full details of the analysis andestimates of internal and external errors in the parameters. Thederivation of the parameters is based on techniques described by theVaucouleurs & Corwin (1977) whereby photoelectric multiaperture dataare fitted by mean Hubble-type-dependent curves which describe theintegral of the B-band flux and the typical B-V and U-B integrated colorgradients. A sophisticated analysis of the residuals of thesemeasurements from the curves was made to allow for the random andsystematic errors that effect such data. The result is a homogeneous setof total magnitudes BTA total colors(B-V)T and (U-B)T, and effective colors(B-V)e and (U-B)e for more than 3000 brightgalaxies in RC3.
| Neutral hydrogen observations of elliptical galaxies
Detection of HI emission from a number of E galaxies is reported. 33galaxies were searched for HI the first time. Seven of the detected Egalaxies are isolated, 9 have nearby companions, and 11 are in compactgroups and/or strongly interacting systems. Nearby confusing sources maybe responsible for some of the detections. The large number ofelliptical galaxies in groups (in this sample) suggests thatgravitational interaction and mergers might be an important source ofsupply of interstellar matter for elliptical galaxies.
| Equilibrium and rotational support of elliptical galaxies
In order to study the contribution of the rotation to the total kineticenergy of elliptical galaxies, we have obtained new rotation curves andvelocity dispersion profiles for 34 galaxies selected for their largeresiduals with respect to the Fundamental Plane. For a sample of 113galaxies from our new observations and the available literature, we haveanalyzed these residuals as a function of the rotational support,quantified by the Vmax/sigma0 parameter. Thecontribution of the rotation to the global equilibrium status ofelliptical galaxies is detected and is found to be in agreement with asimple prediction based on the virial theorem for isotropic rotators.The addition of a rotation term to the Fundamental-Plane relationextends its validity to fast rotators, with even a marginal decrease inits apparent thickness.
| The dependence of the cool matter content on galaxy morphology in galaxies of types E/S0, S0, and SA
Using the material assembled in earlier papers, we examine the manner inwhich the interstellar matter content varies along the Hubble sequencefrom S0 galaxies to Sa galaxies selected from the RSA2 compilation. Forthis we make use of a new and more detailed classification which isdescribed here as applied to these early disk/spiral galaxies. Theprominence of the disk in S0's and the visibility of features (H IIregions) in the Sa's serve as the basis for the subtypes. Three S0categories: subtle, intermediate, and pronounced, and four Sadescriptors: very early, early, intermediate, and late are assigned tothe galaxies. It is found that the total amount of hydrogen (H I + H2)is a function of subtype, being low in the S0's and rising smoothly fromthe early Sa's to the later Sa's. The average surface density ofhydrogen exceeds 3 solar masses/pc-squared only in the latest subtypesof the Sa's. We conclude that the prominence of the disk of a galaxyclosely follows the amount of cool gas which the disk contains.
| 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.
| Groups of galaxies within 80 Mpc. II - The catalogue of groups and group members
This paper gives a catalog of the groups and associations obtained bymeans of a revised hierarchical algorithm applied to a sample of 4143galaxies with diameters larger than 100 arcsec and redshifts smallerthan 6000 km/s. The 264 groups of galaxies obtained in this way (andwhich contain at least three sample galaxies) are listed, with the looseassociations surrounding them and the individual members of eachaggregate as well; moreover, the location of every entity among 13regions corresponding roughly to superclusters is specified. Finally,1729 galaxies belong to the groups, and 466 to the associations, i.e.,the total fraction of galaxies within the various aggregates amounts to53 percent.
| Interstellar matter in early-type galaxies. I - The catalog
A catalog is given of the currently available measurements ofinterstellar matter in the 467 early-type galaxies listed in the secondedition of the Revised Shapley-Ames Catalog of Bright Galaxies. Themorphological type range is E, SO, and Sa. The ISM tracers are emissionin the following bands: IRAS 100 micron, X-ray, radio, neutral hydrogen,and carbon monoxide. Nearly two-thirds of the Es and SOs have beendetected in one or more of these tracers. Additional observed quantitiesthat are tabulated include: magnitude, colors, radial velocity, centralvelocity dispersion, maximum of the rotation curve, angular size, 60micron flux, and supernovae. Qualitative statements as to the presenceof dust or emission lines, when available in the literature, are given.Quantities derivative from the observed values are also listed andinclude masses of H I, CO, X-ray gas, and dust as well as an estimate ofthe total mass and mass-to-luminosity ratio of the individual galaxies.
| Can E and S0 Galaxies Be Distinguished Photometrically?
Modern CCD photometry of early type galaxies does not allow one todifferentiate unambiguously between E and SO galaxies. A de Vaucouleurslaw fits the major axis profiles of SO galaxies as frequently as it doesthose of ellipticals. The data do, however, indicate that exponentialdisks occur more often in SOs than they do in elliptical galaxies.Furthermore, ellipticals exhibit their maximum flattening atintermediate radii more frequently than do SO galaxies.
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