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Eridanus - a supergroup in the local Universe?
We examine a possible supergroup in the direction of the Eridanusconstellation using 6dF Galaxy Survey second data release (6dFGS DR2)positions and velocities together with Two-Micron All-Sky Survey andHyper-Lyon-Meudon Extragalactic DAtabase photometry. We perform afriends-of-friends analysis to determine which galaxies are associatedwith each substructure before examining the properties of theconstituent galaxies. The overall structure is made up of threeindividual groups that are likely to merge to form a cluster of mass ~7× 1013Msolar. We conclude that thisstructure is a supergroup. We also examine the colours, morphologies andluminosities of the galaxies in the region with respect to their localprojected surface density. We find that the colours of the galaxiesredden with increasing density, the median luminosities are brighterwith increasing environmental density and the morphologies of thegalaxies show a strong morphology-density relation. The colours andluminosities of the galaxies in the supergroup are already similar tothose of galaxies in clusters; however, the supergroup contains morelate-type galaxies, consistent with its lower projected surface density.Due to the velocity dispersion of the groups in the supergroup, whichare lower than those of clusters, we conclude that the properties of theconstituent galaxies are likely to be a result of merging orstrangulation processes in groups outlying this structure.
| Spherical models for early-type galaxies with cuspy mass densities
Spherical mass density models are used to fit the central surfacebrightness profiles of early-type galaxies which are generated fromNuker law parameters obtained from the literature. The mass density andthe corresponding potential are in an analytical form. It is shown thatonly a few mass density components are necessary to obtain a good fitand that for all power-law galaxies and for the core galaxies that weconsider, most or all of the mass density components must have cusps toprovide good fits. The applied quadratic programming fitting allows fora method of deprojection, which is reliable and convenient. The resultscan be used directly for further dynamical modelling.
| GMRT HI Observations of the Eridanus Group of Galaxies I.
The GMRT HI 21cm-line observations of galaxies in the Eridanus group arepresented. The Eridanus group, at a distance of ~23 Mpc, is a loosegroup of ~200 galaxies. The group extends to more than 10 Mpc inprojection. The velocity dispersion of the galaxies in the group is ~240km s-1. The galaxies are clustered into different sub-groups. Theoverall population mix of the group is 30% (E + S0) and 70% (Sp + Irr).The observations of 57 Eridanus galaxies were carried out with the GMRTfor ~ 200 h. HI emission was detected from 31 galaxies. The channel rmsof ~1 mJy beam-1 was achieved for most of the image-cubes made with 4 hof data. The corresponding HI column density sensitivity (3σ) is~1 × 1020 cm-2 for a velocity-width of ~ 13.4 km s-1.The 3σ detection lss surface densities, HI disk parameters and HIrotation curves are presented. The velocity fields are analysedseparately for the approaching and the receding sides of the galaxies.These data will be used to study the HI and the radio continuumproperties, the Tully-Fisher relations, the dark matter halos, and thekinematical and HI lopsidedness in galaxies.
| A Chandra View of the Normal S0 Galaxy NGC 1332. I. An Unbroken, Steep Power-Law Luminosity Function for the Low-Mass X-Ray Binary Population
Chandra ACIS -S3 observations of the nearby S0 galaxy NGC 1332 resolvemuch of the X-ray emission into 73 point sources, of which 37 lie withinthe D25 isophote. The remaining galaxy emission compriseshot, diffuse gas and unresolved sources and is discussed in twocompanion papers. The point-source X-ray luminosity function (XLF) showsthe characteristic break seen in other early-type galaxies at~2×1038 ergs s-1. After applying correctionsfor detection incompleteness at low luminosities due to source confusionand contamination from diffuse galactic emission, the break vanishes andthe data are well described as a single power law. This result castsfurther doubt on there being a ``universal'' XLF break in early-typegalaxies, marking the division between neutron star and black holesystems. The logarithmic slope of the differential XLF (dN/dL),β=2.7+/-0.5, is marginally (~2.5 σ) steeper than has beenfound for analogous completeness-corrected fits of other early-typegalaxies but closely matches the behavior seen at high luminosities inthese systems. Two of the sources within D25 areultraluminous X-ray sources (ULXs), although neither haveLX>2×1039 ergs s-1. Theabsence of very luminous ULXs in early-type galaxies suggests a break inthe XLF slope at ~(1-2)×1039 ergs s-1,although the data were not of sufficient quality to constrain such afeature in NGC 1332. The sources have a spatial distribution consistentwith the optical light and display a range of characteristics that areconsistent with an LMXB population. The general spectral characteristicsof the individual sources, as well as the composite source spectra, arein good agreement with observations of other early-type galaxies,although a small number of highly absorbed sources are seen. Two sourceshave very soft spectra, two show strong variability, indicating compactbinary nature, and one source shows evidence of an extended radialprofile. We do not detect a central source in NGC 1332, but we find afaint [LX=(2+/-1)×1038 ergs s-1]point source coincident with the center of the companion dwarf galaxyNGC 1331.
| Redshift-Distance Survey of Early-Type Galaxies: Spectroscopic Data
We present central velocity dispersions and Mg2 line indicesfor an all-sky sample of ~1178 elliptical and S0 galaxies, of which 984had no previous measures. This sample contains the largest set ofhomogeneous spectroscopic data for a uniform sample of ellipticalgalaxies in the nearby universe. These galaxies were observed as part ofthe ENEAR project, designed to study the peculiar motions and internalproperties of the local early-type galaxies. Using 523 repeatedobservations of 317 galaxies obtained during different runs, the dataare brought to a common zero point. These multiple observations, takenduring the many runs and different instrumental setups employed for thisproject, are used to derive statistical corrections to the data and arefound to be relatively small, typically <~5% of the velocitydispersion and 0.01 mag in the Mg2 line strength. Typicalerrors are about 8% in velocity dispersion and 0.01 mag inMg2, in good agreement with values published elsewhere.
| A New Empirical Model for the Structural Analysis of Early-Type Galaxies, and A Critical Review of the Nuker Model
The Nuker law was designed to match the inner few (~3-10) arcseconds ofpredominantly nearby (<~30 Mpc) early-type galaxy light profiles; itwas never intended to describe an entire profile. The Sérsicmodel, on the other hand, was developed to fit the entire profile;however, because of the presence of partially depleted galaxy cores, theSérsic model cannot always describe the very inner region. Wehave therefore developed a new empirical model consisting of an innerpower law, a transition region, and an outer Sérsic model toconnect the inner and outer structure of elliptical galaxies. We haveadditionally explored the stability of the Nuker model parameters.Surprisingly, none are found to be stable quantities; all are shown tovary systematically with a profile's fitted radial extent, and often bymore than 100%. Considering elliptical galaxies spanning a range of 7.5mag, we reveal that the central stellar densities of the underlying hostgalaxies increase with galaxy luminosity until the onset of coreformation, detected only in the brightest elliptical galaxies. Wesuggest that the so-called power-law galaxies may actually be describedby the Sérsic model over their entire radial range.Based on observations made with the NASA/ESA Hubble Space Telescope,obtained at the Space Telescope Science Institute, which is operated bythe Association of Universities for Research in Astronomy, Inc., underNASA contract NAS 5-26555.
| 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
| Redshift-Distance Survey of Early-Type Galaxies. I. The ENEARc Cluster Sample
This paper presents data on the ENEARc subsample of the larger ENEARsurvey of nearby early-type galaxies. The ENEARc galaxies belong toclusters and were specifically chosen to be used for the construction ofa Dn-σ template. The ENEARc sample includes newmeasurements of spectroscopic and photometric parameters (redshift,velocity dispersion, line index Mg2, and the angular diameterdn), as well as data from the literature. New spectroscopicdata are given for 229 cluster early-type galaxies, and new photometryis presented for 348 objects. Repeat and overlap observations withexternal data sets are used to construct a final merged catalogconsisting of 640 early-type galaxies in 28 clusters. Objectivecriteria, based on catalogs of groups of galaxies derived from completeredshift surveys of the nearby universe, are used to assign galaxies toclusters. In a companion paper, these data are used to construct thetemplate Dn-σ distance relation for early-typegalaxies, which has been used to estimate galaxy distances and derivepeculiar velocities for the ENEAR all-sky sample. Based on observationsat Complejo Astronomico El Leoncito, operated under agreement betweenthe Consejo Nacional de Investigaciones Científicas de laRepública Argentina and the National Universities of La Plata,Córdoba, and San Juan; Cerro Tololo Inter-American Observatory,National Optical Astronomical Observatory, which is operated by theAssociation of Universities for Research in Astronomy, Inc., undercooperative agreement with the National Science Foundation; the EuropeanSouthern Observatory (ESO), partially under the ESO-ON agreement; theFred Lawrence Whipple Observatory; the Observatório do Pico dosDias, operated by the Laboratório Nacional de Astrofísicaand the MDM Observatory at Kitt Peak.
| The SBF Survey of Galaxy Distances. IV. SBF Magnitudes, Colors, and Distances
We report data for I-band surface brightness fluctuation (SBF)magnitudes, (V-I) colors, and distance moduli for 300 galaxies. Thesurvey contains E, S0, and early-type spiral galaxies in the proportionsof 49:42:9 and is essentially complete for E galaxies to Hubblevelocities of 2000 km s-1, with a substantial sampling of Egalaxies out to 4000 km s-1. The median error in distancemodulus is 0.22 mag. We also present two new results from the survey.(1) We compare the mean peculiar flow velocity (bulk flow) implied byour distances with predictions of typical cold dark matter transferfunctions as a function of scale, and we find very good agreement withcold, dark matter cosmologies if the transfer function scale parameterΓ and the power spectrum normalization σ8 arerelated by σ8Γ-0.5~2+/-0.5. Deriveddirectly from velocities, this result is independent of the distributionof galaxies or models for biasing. This modest bulk flow contradictsreports of large-scale, large-amplitude flows in the ~200 Mpc diametervolume surrounding our survey volume. (2) We present adistance-independent measure of absolute galaxy luminosity, N and showhow it correlates with galaxy properties such as color and velocitydispersion, demonstrating its utility for measuring galaxy distancesthrough large and unknown extinction. Observations in part from theMichigan-Dartmouth-MIT (MDM) Observatory.
| A NICMOS Survey of Early-Type Galaxy Centers: The Relation Between Core Properties, Gas and Dust Content, and Environment
We present a NICMOS 1.6 μm imaging isophotal study of 27 early-typegalaxies. Core galaxies have reduced ellipticity and boxiness near andwithin their core or break radius. This supports a core formationmechanism that mixes or scatters stars such as scattering caused by abinary black hole. We find the same trends between central surfacebrightness and luminosities as the WPFC studies. We find no correlationbetween core properties and dust mass or X-ray luminosity, suggestingthat processes determining the current gas content (e.g., such as minormergers and cooling flows) are unrelated to processes occurring duringcore formation. Core galaxies exist in a variety of environments rangingfrom poor groups to large clusters. A combined sample suggests thatgalaxy groups may harbor more luminous power-law galaxies than clusterssuch as Virgo and Fornax. Based on observations with the NASA/ESA HubbleSpace Telescope obtained at the Space Telescope Science Institute, whichis operated by the Association of University for Research in Astronomy,Inc. (AURA), under NASA contract NAS5-26555.
| Luminosity Profiles of Merger Remnants
Using published luminosity and molecular gas profiles of the late-stagemergers NGC 3921, NGC 7252, and Arp 220, we examine the expectedluminosity profiles of the evolved merger remnants, especially in lightof the massive CO complexes that are observed in their nuclei. For NGC3921 and NGC 7252, we predict that the resulting luminosity profileswill be characterized by an r^1/4 law. In view of previous optical workon these systems, it seems likely that they will evolve into normalelliptical galaxies as regards their optical properties. Due to a muchhigher central molecular gas column density, Arp 220 might not evolvesuch a ``seamless'' light profile. We conclude that ultraluminousinfrared mergers such as Arp 220 either evolve into elliptical galaxieswith anomalous luminosity profiles or do not produce many low-mass starsout of their molecular gas complexes.
| The Southern Sky Redshift Survey
We report redshifts, magnitudes, and morphological classifications for5369 galaxies with m_B <= 15.5 and for 57 galaxies fainter than thislimit, in two regions covering a total of 1.70 sr in the southerncelestial hemisphere. The galaxy catalog is drawn primarily from thelist of nonstellar objects identified in the Hubble Space TelescopeGuide Star Catalog (GSC). The galaxies have positions accurate to ~1"and magnitudes with an rms scatter of ~0.3 mag. We compute magnitudes(m_SSRS2) from the relation between instrumental GSC magnitudes and thephotometry by Lauberts & Valentijn. From a comparison with CCDphotometry, we find that our system is homogeneous across the sky andcorresponds to magnitudes measured at the isophotal level ~26 magarcsec^-2. The precision of the radial velocities is ~40 km s^-1, andthe redshift survey is more than 99% complete to the m_SSRS2 = 15.5 maglimit. This sample is in the direction opposite that of the CfA2; incombination the two surveys provide an important database for studies ofthe properties of galaxies and their large-scale distribution in thenearby universe. Based on observations obtained at Cerro TololoInter-American Observatory, National Optical Astronomy Observatories,operated by the Association of Universities for Research in Astronomy,Inc., under cooperative agreement with the National Science Foundation;Complejo Astronomico El Leoncito, operated under agreement between theConsejo Nacional de Investigaciones Científicas de laRepública Argentina and the National Universities of La Plata,Córdoba, and San Juan; the European Southern Observatory, LaSilla, Chile, partially under the bilateral ESO-ObservatórioNacional agreement; Fred Lawrence Whipple Observatory;Laboratório Nacional de Astrofísica, Brazil; and the SouthAfrican Astronomical Observatory.
| Spiral Galaxies with WFPC2. III. Nuclear Cusp Slopes
In this paper, the third of a series dedicated to the investigation ofthe nuclear properties of spiral galaxies, we (1) model the Wide FieldPlanetary Camera 2 F606W nuclear surface brightness profiles of 41spiral galaxies presented in Papers I and II with the analytic lawintroduced by Lauer et al. and (2) deconvolve these surface brightnessprofiles and their analytic fits, so as to estimate the nuclear stellardensities of bulges of spiral galaxies. We find that the nuclear stellarcusps (quantified by the average logarithmic slope of the surfacebrightness profiles within 0.1"-0.5") are significantly different forR^1/4 law and exponential bulges. The former have nuclear propertiessimilar to those of early-type galaxies, i.e., similar values of nuclearcusps for comparable luminosities, and increasingly steeper stellarcusps with decreasing luminosity. By contrast, exponential bulges have(underlying the light contribution from photometrically distinct,central compact sources) comparatively shallower stellar cusps, andlikely lower nuclear densities, than R^1/4 law bulges. Based onobservations with the NASA/ESA Hubble Space Telescope, obtained at theSpace Telescope Science Institute, which is operated by the Associationof Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.
| 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.
| Ellipticals with Kinematically Distinct Cores: V-I Color Images with WFPC2
We have analyzed Hubble Space Telescope WFPC2 F555W and F814W (i.e., Vand I) images for 15 elliptical galaxies with kinematically distinctcores. For each of them, we have derived surface brightness andisophotal parameter profiles in the two bands, color maps, and radialprofiles in V - I. Most galaxies show patchy dust absorption close totheir nuclei. However, there are generally no indications ofhomogeneous, diffuse dust components close to the nuclei. The nuclearcolors in the unobscured regions are most likely representative of thecentral stellar populations. We have detected photometric evidence forfaint stellar disks, on scales of a few tens to a few arcseconds, inseven galaxies, namely NGC 1427, 1439, 1700, 4365, 4406, 4494, and 5322.In NGC 1700, the isophotes are slightly boxy at the scale of thecounterrotating component and disky at larger radii. We find nodifference in V - I color greater than 0.02 mag between these disks andthe surrounding galactic regions. Hence, the stellar populations in thekinematically distinct cores are not strongly deviant from thepopulation of the main body. Specifically, there is no evidence for adominating population of blue, very metal weak stars as predicted bysome of the formation scenarios. This argues against models in whichsmall galaxies fall in and survive in the nuclei, unless supermassiveblack holes are present. These would likely disrupt the accreted smallsystems. For one galaxy, NGC 4365, the innermost region is bluer thanthe surrounding regions. This area extends to ~15 pc and contains aluminosity of ~2.5 x 106 Lȯ. If interpreted as a stellar populationeffect, an age difference of ~3--4 Gyr, or an [Fe/H] variation of about0.2 dex, is derived. The nuclear intensity profiles show a largevariety: some galaxies have steep cusp profiles, while others haveshallow cusps and a "break radius." The nuclear cusps of galaxies withkinematically distinct cores follow the same trends as the nuclei ofnormal galaxies. We have not been able to identify a unique, qualifyingfeature in the WFPC2 images that distinguishes the galaxies withkinematically distinct cores from the kinematically normal cores. It ispossible that statistical differences exist: possibly, the kinematicallydistinct cores have a higher fraction of nuclear disks. The similarityof both types of cores puts strong constraints on the formationscenarios. Simulations of galaxy mergers, with the inclusion of starformation and nuclear black holes, are needed to resolve the question ofhow these structures may have formed. Spectra with high spatialresolution are needed to study the nuclear structure of the distinctcomponent in detail.
| The Centers of Early-Type Galaxies with HST. IV. Central Parameter Relations.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114.1771F&db_key=AST
| X-Ray Constraints on the Intrinsic Shape of the Lenticular Galaxy NGC 1332
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJ...457..177B&db_key=AST
| The Centers of Early-Type Galaxies With HST. III. Non-Parametric Recovery of Stellar Luminosity Distribution
We have non-parametrically determined the luminosity density profilesand their logarithmic slopes for 42 early-type galaxies observed withHST. Assuming that the isodensity contours are spheroidal, then theluminosity density is uniquely determined from the surface brightnessdata through the Abel equation. For nearly all the galaxies in oursample, the logarithmic slope of the luminosity density (S = d log v/dlog r) measured at 0.1" (the innermost reliable measurement with theuncorrected HST) is significantly different from zero; i.e., mostelliptical galaxies have cusps. There are only two galaxies for which ananalytic core (S approaches 0) cannot be excluded. The distribution oflogarithmic slopes at 0.1" appears to be bimodal, confirming theconclusion of Lauer et al. [AJ, 110,2622(1995)] that early-type galaxiescan be divided into two types based on their surface brightnessprofiles; i.e., those with cuspy cores and those whose steep power-lawprofiles continue essentially unchanged in to the resolution limit. Thepeaks in the slope distribution occur at S = -0.8 and - 1.9. More thanhalf of the galaxies have slopes steeper than - 1.0. Taken together withthe recent theoretical work of Merritt and Fridman, these resultssuggest that many (and maybe most) elliptical galaxies are either nearlyaxisymmetric or spherical near the center, or slowly evolve due to theinfluence of stochastic orbits.
| The Centers of Early-Type Galaxies With HST. II. Empirical Models and Structural Parameters
We present a set of structural parameters for the central parts of 57early-type galaxies observed with the Planetary Camera of the HubbleSpace Telescope. These parameters are based on a new empirical law thatsuccessfully characterizes the centers of early-type galaxies. Thisempirical law assumes that the surface brightness profile is acombination of two power laws with different slopes γ and βfor the inner and outer regions. Conventional structural parameters suchas core radius and central surface brightness are replaced by breakradius r_b_, where the transition between power-law slopes takes place,and surface brightness μ_b_ at that radius. An additional parameterα describes the sharpness of the break. The structural parametersare derived using a X^2^ minimization process applied to the meansurface brightness profiles. The resulting model profiles generally givevery good agreement to the observed profiles out to the radius of ~10"imaged by the Planetary Camera. Exceptions include galaxies which departfrom pure power laws at large radius, those with strong nuclearcomponents, and galaxies partly obscured by dust. The uncertainties inthe derived parameters are estimated using Monte Carlo simulations whichtest the stability of solutions in the face of photon noise and theeffects of the deconvolution process. The covariance of the structuralparameters is examined by computing contours of constant X^2^ inmulti-dimensional parameter space.
| The Centers of Early-Type Galaxies with HST.I.An Observational Survey
We have obtained V-band images of 45 nearby elliptical galaxies andbulges using the original Planetary Camera of the Hubble SpaceTelescope. The majority of the sample is at distances of 10-20 Mpc. Thisrepresents a substantial increase in the number of galaxies that havebeen studied at a resolution of a few parsecs. At this resolution, manygalaxies reveal previously unknown central disks, dust clouds, andnuclear components. We find that galaxies have two types of brightnessprofiles. The first type consists of galaxies that have cores. Thesegalaxies have brightness profiles that "break" from steep outer powerlaws to shallow inner cusps. The core class includes many galaxies thathad cores apparently resolved from the ground. The second type consistsof galaxies that have profiles that continue into the resolution limitas steep power laws, showing no evidence of cores of any sort. We thusfind that all galaxies studied so far have singular brightness profilesin the sense that I(r) ~ r^-γ^ as r - 0.1", with 0 < γ< 0.3 at the few parsec scale for galaxies with cores, and γ ~1 for power-law galaxies. No galaxies in our sample have a centralregion that is constant in surface brightness. This implies that thestellar density in these systems is still increasing steeply at the HSTresolution limit. Many galaxies reach stellar mass densities of ~5 x10^4^ M_sun_ pc^-3^ at the resolution limit, appearing similar in formto M32 at radii of a few parsecs. The core and power-law profile classescorrespond to the Jaffe et al. (AJ, 108, 1567 (1994)] Type I and IIprofiles; however, we disagree with their suggestion that the presenceof a central stellar disk is closely related to, or even determines,profile type. Power-law galaxies are seen at all ellipticities, and themajority of them show no evidence for central disks.
| 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.
| General study of group membership. II - Determination of nearby groups
We present a whole sky catalog of nearby groups of galaxies taken fromthe Lyon-Meudon Extragalactic Database. From the 78,000 objects in thedatabase, we extracted a sample of 6392 galaxies, complete up to thelimiting apparent magnitude B0 = 14.0. Moreover, in order to considersolely the galaxies of the local universe, all the selected galaxieshave a known recession velocity smaller than 5500 km/s. Two methods wereused in group construction: a Huchra-Geller (1982) derived percolationmethod and a Tully (1980) derived hierarchical method. Each method gaveus one catalog. These were then compared and synthesized to obtain asingle catalog containing the most reliable groups. There are 485 groupsof a least three members in the final catalog.
| On the relationship between radio emission and optical properties in early-type galaxies
To study the origin of radio activity in early-type galaxies, thepossible dependence of their radio emission on basic optical parameters,such as the absolute magnitude, the central velocity dispersion sigma,and the mean surface brightness mu is explored. A sample of 743 E and SOgalaxies is used which is based on three independent radio surveys ofoptically selected galaxies with virtually complete information onmagnitudes, morphological types, redshift distances, diameters, andradio fluxes. For both E and SO galaxies, only the absolute magnitudeappears to be directly related to the radio activity, while sigma and mudo not. Also, a significant dependence of the apparent flattening onradio power is confirmed for E galaxies. Some relevant implications ofthese results are discussed.
| Spectroscopy and photometry of elliptical galaxies. III - UBV aperture photometry, CCD photometry, and magnitude-related parameters
Photoelectric aperture photometry of nearly 2000 individual observationsof 449 elliptical galaxies combined with published measurements usingthe self-consistent UVB color catalog developed by Burstein et al.(1987) are presented. The data are placed on a standard magnitude andcolor system, and 'total' magnitudes and effective diameters are derivedby comparison with the standard elliptical magnitude growth curve. Agraphical representation of the standard growth curve and the residualsfrom it for each galaxy are given, and a new diameter measurement Dn ispresented which can be measured reliably for elliptical galaxies andserves as an accurate distance indicator when combined with centralvelocity dispersion. Individual magnitudes, surface brightnesses,effective diameters, and values of Dn are summarized for each galaxy incatalog form.
| HI-observations of galaxies in the Kraan-Korteweg - Tammann catalogue of nearby galaxies. I - The data
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1986A&AS...63..323H&db_key=AST
| Southern Galaxy Catalogue.
Not Available
| Velocity dispersion profiles of clusters of galaxies
Line-of-sight velocity dispersion profiles (sigma profiles) arepresented for 13 clusters of galaxies having at least 30 radialvelocities. The clusters considered include A2151, A1367, Virgo, A426,A1656, A2199, Cancer, A194, Fornax, A262, Centaurus, A2319, and PegasusI. All the sigma profiles are fitted to simple power laws over theradial interval from 0.1 to 2.0 times the virial radius and are found tofall into four classifications. In view of the amount of masssegregation implied, the amount of central concentration observed, andthe predominant galaxy morphology, it is suggested that theseclassifications represent a dynamical age sequence. Statistical testsare applied to two features appearing in some sigma profiles: thepresence of a local minimum that coincides with the local minimum notedin surface density or surface brightness profiles and a decrease inline-of-sight velocity dispersion in the cores of certain clusters.Possible dynamical implications of these features are discussed in termsof Wielen's (1974) N-body simulations.
| A 5-GHz survey of bright Southern elliptical and S0 galaxies
The Parkes 64-m telescope has been used in a 5.0-GHz survey of 181Southern E and S0 galaxies from the Reference catalogue of brightgalaxies. Of the 39 detections above the nominal limit of 12 mJy, 15 arenew, several have radio spectra indicating membership in the activeclass, and two have shown intensity variations at centimeterwavelengths. The results of this survey combined with results fromearlier surveys of lower sensitivity suggest that only about 40 per centof the E/S0 galaxies in the Reference catalogue have a flux density at 5GHz exceeding 1 mJy.
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