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Stellar Populations in Nearby Lenticular Galaxies
We have obtained two-dimensional spectral data for a sample of 58 nearbyS0 galaxies with the Multi-Pupil Fiber/Field Spectrograph of the 6 mtelescope of the Special Astrophysical Observatory of the RussianAcademy of Sciences. The Lick indices Hβ, Mg b, and arecalculated separately for the nuclei and for the bulges taken as therings between R=4'' and 7", and the luminosity-weighted ages,metallicities, and Mg/Fe ratios of the stellar populations are estimatedby comparing the data to single stellar population (SSP) models. Fourtypes of galaxy environments are considered: clusters, centers ofgroups, other places in groups, and the field. The nuclei are found tobe on average slightly younger than the bulges in any type ofenvironment, and the bulges of S0 galaxies in sparse environments areyounger than those in dense environments. The effect can be partlyattributed to the well-known age correlation with the stellar velocitydispersion in early-type galaxies (in our sample the galaxies in sparseenvironments are on average less massive than those in denseenvironments), but for the most massive S0 galaxies, withσ*=170-220 km s-1, the age dependence on theenvironment is still significant at the confidence level of 1.5 σ.Based on observations collected with the 6 m telescope (BTA) at theSpecial Astrophysical Observatory (SAO) of the Russian Academy ofSciences (RAS).
| Stellar Kinematics of Boxy Bulges: Large-Scale Bars and Inner Disks
Long-slit stellar kinematic observations were obtained along the majoraxis of 30 edge-on spiral galaxies, 24 with a boxy or peanut-shaped(B/PS) bulge and six with other bulge types for comparison. Such B/PSbulges are identified in at least 45% of highly inclined systems, and agrowing body of theoretical and observational work suggests that theyare the edge-on projection of thickened bars. Profiles of the meanstellar velocity V, the velocity dispersion σ, as well as theasymmetric (h3) and symmetric (h4) deviations froma pure Gaussian are presented for all objects. Comparing these profileswith stellar kinematic bar diagnostics developed from N-bodysimulations, we find bar signatures in 24 of our sample galaxies (80%).Galaxies with a B/PS bulge typically show a double-humped rotation curvewith an intermediate dip or plateau. They also frequently show a ratherflat central velocity dispersion profile accompanied by a secondary peakor plateau, and numerous galaxies have a local central σ minimum(>~40%). The h3 profiles display up to three slopereversals. Most importantly, h3 is normally correlated with Vover the presumed bar length, contrary to expectations from axisymmetricdisks. These characteristic bar signatures strengthen the case for aclose relationship between B/PS bulges and bars and leave little roomfor other explanations of the bulges' shape. We also find thath3 is anticorrelated with V in the very center of mostgalaxies (>~60%), indicating that these objects additionally harborcold and dense decoupled (quasi-) axisymmetric central stellar disks,which may be related to the central light peaks. These central diskscoincide with previously identified star-forming ionized-gas disks(nuclear spirals) in gas-rich systems, and we argue that they formed outof gas accumulated by the bar at its center through inflow. As suggestedby N-body models, the asymmetry of the velocity profile (h3)appears to be a reliable tracer of asymmetries in disks, allowing us todiscriminate between axisymmetric and barred disks seen in projection.B/PS bulges (and thus a large fraction of all bulges) appear to be madeup mostly of disk material, which has acquired a large vertical extentthrough bar-driven vertical instabilities. Their formation is thusprobably dominated by secular evolution processes rather than merging.
| Inner Polar Rings in Regular Lenticular Galaxies
We have investigated a sample of S0 galaxies, mostly with circumnucleardust lanes orthogonal to their major axes, chosen from Hubble SpaceTelescope Wide Field Planetary Camera 2 images. Two-dimensionalspectroscopy undertaken with the Multipupil Fiber Spectrograph of the 6m telescope of the Special Astrophysical Observatory of the RussianAcademy of Sciences has revealed that indeed the ionized gas in thecenters of these eight lenticular galaxies rotate in the planes nearlyorthogonal to the rotation (and symmetry) planes of their centralstellar components. Although almost all the galaxies are located indense environments, an external origin of this rotation plane tilt isnot obvious because all the galaxies but one are known to have extendedH I disks, and in two cases where the angular resolution of H Iobservations allows, we find orthogonality of the external H I and innerionized gas disks. We discuss a possible relation of the inner gas polarrings to a triaxiality of galactic potential. The stellar populations inthe nuclei of all but two galaxies are very old, which excludes recentstar formation bursts and proves that the polar orbits of thecircumnuclear gas are rather stable. In the nuclei of NGC 2655 and NGC4111, we have found signatures of star formation bursts some 1.5-2 Gyrago. This finding can be related to very central gas in NGC 2655, whichis coplanar to the circumnuclear stellar disk and to radial gas inflowin NGC 4111; just these gas reservoirs and not the polar rings may beresponsible for fueling nuclear star formation.Partly based on observations collected with the 6 m telescope at theSpecial Astrophysical Observatory of the Russian Academy of Sciences.
| Redshift-Distance Survey of Early-Type Galaxies: Circular-Aperture Photometry
We present R-band CCD photometry for 1332 early-type galaxies, observedas part of the ENEAR survey of peculiar motions using early-typegalaxies in the nearby universe. Circular apertures are used to tracethe surface brightness profiles, which are then fitted by atwo-component bulge-disk model. From the fits, we obtain the structuralparameters required to estimate galaxy distances using theDn-σ and fundamental plane relations. We find thatabout 12% of the galaxies are well represented by a pure r1/4law, while 87% are best fitted by a two-component model. There are 356repeated observations of 257 galaxies obtained during different runsthat are used to derive statistical corrections and bring the data to acommon system. We also use these repeated observations to estimate ourinternal errors. The accuracy of our measurements are tested by thecomparison of 354 galaxies in common with other authors. Typical errorsin our measurements are 0.011 dex for logDn, 0.064 dex forlogre, 0.086 mag arcsec-2 for<μe>, and 0.09 for mRC,comparable to those estimated by other authors. The photometric datareported here represent one of the largest high-quality and uniformall-sky samples currently available for early-type galaxies in thenearby universe, especially suitable for peculiar motion studies.Based on observations at Cerro Tololo Inter-American Observatory (CTIO),National Optical Astronomy Observatory, which is operated by theAssociation of Universities for Research in Astronomy, Inc., undercooperative agreement with the National Science Foundation (NSF);European Southern Observatory (ESO); Fred Lawrence Whipple Observatory(FLWO); and the MDM Observatory on Kitt Peak.
| 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 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.
| Box- and peanut-shaped bulges. I. Statistics
We present a classification for bulges of a complete sample of ~ 1350edge-on disk galaxies derived from the RC3 (Third Reference Catalogue ofBright Galaxies, de Vaucouleurs et al. \cite{rc3}). A visualclassification of the bulges using the Digitized Sky Survey (DSS) inthree types of b/p bulges or as an elliptical type is presented andsupported by CCD images. NIR observations reveal that dust extinctiondoes almost not influence the shape of bulges. There is no substantialdifference between the shape of bulges in the optical and in the NIR.Our analysis reveals that 45% of all bulges are box- and peanut-shaped(b/p). The frequency of b/p bulges for all morphological types from S0to Sd is > 40%. In particular, this is for the first time that such alarge frequency of b/p bulges is reported for galaxies as late as Sd.The fraction of the observed b/p bulges is large enough to explain theb/p bulges by bars. Partly based on observations collected at ESO/LaSilla (Chile), DSAZ/Calar Alto (Spain), and Lowell Observatory/Flagstaff(AZ/U.S.A.). Tables 6 and 7 are only available in electronic form at CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| On the relationship between age and dynamics in elliptical galaxies
Galaxy age estimates (mostly from spectroscopy of the central regions)are now available for many early-type galaxies. In a previous paper weshowed that the offset of galaxies from the fundamental plane depends ongalaxy age. Here, using the same sample of 88 galaxies, we examine thescatter about the Faber-Jackson (FJ) relation, and find that theposition of a galaxy relative to this relation depends on its age. Inparticular, younger ellipticals are systematically brighter inMB and/or have a lower central velocitydispersion (σ0). The mean relation corresponds togalaxies that are ~10Gyr old. We attempt to reproduce the observed trendof the FJ residuals with age using two simple models. The first assumesthat galaxy age is tracing the last major star formation event in anelliptical galaxy. We assume that this starburst was instantaneous,centrally located and involved 10per cent of the galaxy by mass. Thefading of this burst changes the MBcomponent of the FJ residuals, with time. Such a model was verysuccessful at reproducing the B-V and Mg2 evolution reportedin our previous paper, but is unable to reproduce the strength of the FJtrend. A second model is required to describe age-correlated changes ingalaxy dynamics. Following expectations from cosmological simulations,we assume that σ0, for a galaxy of a given mass, scaleswith the epoch of galaxy formation, i.e. with the mean density of theUniverse. Hence recently formed ellipticals have systematically lowervelocity dispersions than do old ellipticals. We find that a combinationof these two models provides a good match to the change in FJ residualswith galaxy age. This suggests that young ellipticals will have subtlydifferent dynamical properties from old ellipticals. We also find thatthere is not a strong relationship between the age of a galaxy and itsluminosity for our sample. This suggests that the tilt of thefundamental plane is not totally driven by age.
| 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.
| 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
| A simple kinematic modeling for flattened S0 galaxies
We present mass models for three S0 galaxies with a strong diskcomponent observed almost on edge (NGC 2732, NGC 4111, and NGC 4350).For the analytical representation of the surface-brightnessdistribution, the method of Multi- Gaussian Expansion, first presentedby Monnet et al. (\cite{MBE92}: A&A 253, 366) is applied to V-bandsurface photometry. A simplified dynamical model is adopted, and thecalculated kinematic profiles are compared to long-slit spectroscopicdata; overall agreement is reached, except for the innermost region,where additional mass is needed for all three galaxies. We discusspossible applications. Based in part on observations collected at theObservatoire de Haute-Provence.
| Molecular Gas, Morphology, and Seyfert Galaxy Activity
We probe the cause of the elevated star formation in host galaxies ofSeyfert 2 nuclei compared with Seyfert 1 hosts and with field galaxies.12CO (1--0) observations of a large sample of Seyfert galaxies indicateno significant difference in the total amount of molecular gas as afunction of the Seyfert nuclear type, nor are Seyfert galaxiessignificantly different in this regard from a sample of field galaxiesonce selection effects are accounted for. Therefore, the total amount ofmolecular gas is not responsible for the enhanced star-forming activityin Seyfert 2 hosts. To probe how this gas is being converted moreefficiently into stars in Seyfert 2 hosts than in the other galaxies, weinvestigate the occurrence of bars, interactions, and distortedmorphologies among Seyfert galaxies. We find a significantly higher rateof asymmetric morphologies for Seyfert 2 galaxies with respect toSeyfert 1 galaxies and field galaxies. Relative to field galaxies, theeffect is at a greater than 99.9% confidence level. The presence ofasymmetric morphologies in individual Seyfert galaxies is correlatedwith their tendency to exhibit enhanced star-forming activity. Theseresults suggest that asymmetric morphologies are an important cause forthe link between Seyfert type and star-forming activity: bars anddistortions in Seyfert 2 hosts are likely both to enhance star-formingactivity and to funnel gas into the nuclear region, thus obscuring andpossibly contributing to the feeding of the active nucleus.
| 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)
| Kinematical data on early-type galaxies. I.
As part of an ongoing program on the main parameters of early-typegalaxies, we have performed long-slit absorption spectroscopy on asample of 21 ellipticals and S0s. We present determinations of thecentral velocity dispersion and, for 18 objects, velocity-dispersionprofiles and rotation curves. Table 4 is presented in electronic formonly; Tables 3 and 4 are available from the CDS, Strasbourg (anonymousftp to 130.79.128.5). Based on observations collected at theObservatoire de Haute-Provence.
| Disk structure and kinematics of S0 galaxies.
The photometric and kinematic structure of 15 nearly edge-on S0 galaxiesand one bulge dominated spiral galaxy has been investigated on the basisof a decomposition method applied to CCD data. The method consists inthe construction of a bulge model by masking the isophote regionaffected by the disk. The subtraction of this model yields the surfacebrightness distribution of the disk. It has been found that asignificant number of the objects possess two disks: the main, outerdisk having an inner cut-off and a steeper inner disk. The radial run ofthe a_4_/a parameter (which shows two or three maxima) supports thisfinding. Wiggles in the rotation curve of the galaxies are clearlyconnected to the observed two-disk structure. They are not caused byintrinsically peculiar kinematics of the objects, but simply by thesuperposition of the (hot) bulge component and the two (cold) diskcomponents. In several objects we find ring-like structures. These arelocated near the turnover radius of the rotation curve.
| 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.
| 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.
| Quantitative morphology of E-S0 galaxies. III. Coded and parametric description of 108 galaxies in a complete sample
A survey has been performed of the morphological and photometricproperties of 108 E-S0 galaxies out of a complete sample of 112: thissample is built from the Revised Shapley-Ames Catalogue (RSA, Sandage& Tammann, 1981) keeping objects with δ>-10deg andV_0_<3000km/s, rejecting SB0's and Local Group dwarfs. The data weremainly derived from our CCD observations at Observatoire deHaute-Provence: the camera allowed fields of 4x7 arcmin (or 7x7 for thelast run), the seeing being generally in the 2-3 arcsec FWHM range. Themeasurements include the isophotal analysis according to Carter's(1978), principles,and the photometric profiles along the two main axis.Opposite semi-axis are measured separately to detect asymmetries.Partial results about strongly flattened galaxies were given anddiscussed in Paper I and II of this series (Michard & Marchal, 1993and 1994). The present paper gives in tabular form: - in Table 2a, 2bthe most useful morphological parameters and a coded description of the108 studied objects. This table includes a revised classificationaccording to Hubble types, this being completed by the subclassificationof ellipticals into "boxy", "disky" and "undeterminate". It alsoincludes the classifications of envelope geometry and disk extent, asintroduced in Paper I. - in Table 3a, b the usual photometric globalparameters, also converted to absolute units for future reference. Thetabular data is completed by individual notes for each galaxy, collectedin an Appendix. A discussion of the present data will be presented in aforthcoming Paper IV : it aims at checking the working hypothesis thatgalaxies of both E and S0 Hubble types belong, but for a small minority,to a common population of objects with similar structures.
| Quantitative Morphology of E / s0 Galaxies - Part Two - Possible Environmental Effects on the Properties of Lenticular Galaxies
In Paper I of this series (Michard & Marchal 1993) "E-like S0s" weredefined as objects without ring nor lens, and with the disk fullyembedded in a spheroidal halo. It was tentatively suggested that suchobjects might be comparatively more frequent in the Virgo cluster thanin the general field, as is known to be the case for ellipticals. Thisquestion is reconsidered with an enlarged set of S0s (now nearlycomplete) and a much enlarged (and now complete) Virgo subset: theprevious suggestion is confirmed.
| 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.
| Quantitative morphology of E-S0 galaxies. I - Bulge, lens, disk, and envelope in edge-on systems
Surface photometry of 37 nearly edge-on, nonbarred E-S0 galaxies ispresented. Inner rings are found in more than half of the S0-classifiedobjects. An 'outer lens' may be seen in nine objects, seven showing bothouter lens and 'ring-lens'. Preliminary statistics are given on diskswhich are fully embedded in the envelope, mixed with it, or extendoutwards without a noticeable envelope. The E-classified galaxies in thesample show no ring, and all the disks are fully embedded except in onecase. The f4 asymmetry expressed by small trends in major axis positionangle and nonzero value of Carter's coefficient f4 of sin 4 omega isclearly shown by 10 objects in the sample.
| Largescale Extinction Effects in the Disk of s0 Galaxies
B and V-band, or multicolor surface photometry of 24 highly- inclined S0galaxies shows frequent asymmetries in the luminosity profiles. A classof minor-axis asymmetries with amplitude increasing blueward may beinterpreted as internal absorption of the bulge light by an extended,galaxian-size equatorial dust layer; this phenomenon might occur in40-50% of S0s. The modelling of two representative objects shows thedata to be consistent with an obscuration of the order of A_v_ = 0.1magnitude (corrected to face-on), with possibly a ring-like geometry ofthe dust layer, similar to the H I distribution observed in many S0s.However, our data do not put tight constraints on the spatialdistribution of the absorbing material, except on its characteristicscale, and we are unable to discriminate between a continuous and apatchy layer.
| Correlations between UBV colors and fine structure in E and S0 galaxies - A first attempt at dating ancient merger events
New high-quality UBV colors of E and S0 galaxies compiled in the RC3 areanalyzed, and correlations between them and the fine-structure indexSigma are explored. The color residuals Delta(U-B)e,0, Delta(B-V)e,0,and Delta(U-V)e,0 (where e refers to the effective or half-lightaperture) correlate with Sigma for 35 E and 34 S0 galaxies bothseparately and combined. Typical coefficients are -0.4 to -0.6, and theslopes of the mean relations are significant at the 2.1 sigma-4.2 sigmalevel. The new correlations show that the detected systematic variationsare not limited to the nuclei, but occur globally in the stellarpopulations of E and S0 galaxies. The color residuals and previouslydetermined line-strength residuals correlate closely, demonstrating thatit is cosmic scatter that dominates the vertical scatter in thecolor-magnitude and line-strength-magnitude relations. It is suggestedthat the deviations in color and line strength from mean relations havea common physical cause which, because of the correlations with finestructure, is probably a variation in the mean age of the stellarpopulations.
| 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.
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