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A wide-field photometric study of the globular cluster system of NGC 4636
Previous smaller-scale studies of the globular cluster system of NGC4636, an elliptical galaxy in the southern part of the Virgo cluster,have revealed an unusually rich globular cluster system. Were-investigate the cluster system of NGC 4636 with wide-field Washingtonphotometry. The globular cluster luminosity function can be followedroughly 1 mag beyond the turn-over magnitude found at {V} =23.31±0.13 for the blue cluster sub-population. This correspondsto a distance modulus of ({m}-{M})=31.24±0.17, 0.4 mag largerthan the distance determined from surface brightness fluctuations. Thehigh specific frequency is confirmed, yet the exact value remainsuncertain because of the uncertain distance: it varies between5.6±1.2 and 8.9±1.2. The globular cluster system has aclearly bimodal color distribution. The color peak positions show noradial dependence and are in good agreement with the values found forother galaxies studied in the same filter system. However, a luminositydependence is found: brighter clusters with an“intermediate” color exist. The clusters exhibit a shallowradial distribution within 7´, represented by a power-law with anexponent of -1.4. Within the same radial interval, the galaxy light hasa distinctly steeper profile. Because of the difference in the clusterand light distribution the specific frequency increases considerablywith radius. At 7´ and 9´ the density profiles of the redand blue clusters, respectively, change strongly: the power-law indicesdecrease to around -5 and become similar to the galaxy profile. Thissteep profile indicates that we reach the outer rim of the clustersystem at approximately 11´. This interpretation is supported bythe fact that in particular the density distribution of the blue clusterpopulation can be well fit by the projection of a truncated power-lawmodel with a core. This feature is seen for the first time in a globularcluster system. While the radial distribution of the cluster and fieldpopulations are rather different, this is not true for the ellipticityof the system: the elongation as well as the position angle of thecluster system agree well with the galaxy light. We compare the radialdistribution of globular clusters with the light profiles for a sampleof elliptical galaxies. The difference observed in NGC 4636 is typicalof an elliptical galaxy of this luminosity. The intrinsic specificfrequency of the blue population is considerably larger than that of thered one.Tables A.1 to A.6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/433/43
| The relationship between the Sérsic law profiles measured along the major and minor axes of elliptical galaxies
In this paper we discuss the reason why the parameters of theSérsic model best-fitting the major axis light profile ofelliptical galaxies can differ significantly from those derived for theminor axis profile. We show that this discrepancy is a naturalconsequence of the fact that the isophote eccentricity varies with theradius of the isophote and present a mathematical transformation thatallows the minor axis Sérsic model to be calculated from themajor axis model, provided that the elliptical isophotes are aligned andconcentric and that their eccentricity can be represented by a wellbehaved, though quite general, function of the radius. When there is novariation in eccentricity only the effective radius changes in theSérsic model, while for radial-dependent eccentricity thetransformation, which allows the minor axis Sérsic model to becalculated from the major axis model is given by the Lerch Φtranscendental function. The proposed transformation was tested usingphotometric data for 28 early-type galaxies.
| A Catalog of Neighboring Galaxies
We present an all-sky catalog of 451 nearby galaxies, each having anindividual distance estimate D<~10 Mpc or a radial velocityVLG<550 km s-1. The catalog contains data onbasic optical and H I properties of the galaxies, in particular, theirdiameters, absolute magnitudes, morphological types, circumnuclearregion types, optical and H I surface brightnesses, rotationalvelocities, and indicative mass-to-luminosity and H I mass-to-luminosityratios, as well as a so-called tidal index, which quantifies the galaxyenvironment. We expect the catalog completeness to be roughly 70%-80%within 8 Mpc. About 85% of the Local Volume population are dwarf (dIr,dIm, and dSph) galaxies with MB>-17.0, which contributeabout 4% to the local luminosity density, and roughly 10%-15% to thelocal H I mass density. The H I mass-to-luminosity and the H Imass-to-total (indicative) mass ratios increase systematically fromgiant galaxies toward dwarfs, reaching maximum values about 5 in solarunits for the most tiny objects. For the Local Volume disklike galaxies,their H I masses and angular momentum follow Zasov's linear relation,expected for rotating gaseous disks being near the threshold ofgravitational instability, favorable for active star formation. We foundthat the mean local luminosity density exceeds 1.7-2.0 times the globaldensity, in spite of the presence of the Tully void and the absence ofrich clusters in the Local Volume. The mean local H I density is 1.4times its ``global'' value derived from the H I Parkes Sky Survey.However, the mean local baryon densityΩb(<8Mpc)=2.3% consists of only a half of the globalbaryon density, Ωb=(4.7+/-0.6)% (Spergel et al.,published in 2003). The mean-square pairwise difference of radialvelocities is about 100 km s-1 for spatial separations within1 Mpc, increasing to ~300 km s-1 on a scale of ~3 Mpc. alsoWe calculated the integral area of the sky occupied by the neighboringgalaxies. Assuming the H I size of spiral and irregular galaxies to be2.5 times their standard optical diameter and ignoring any evolutioneffect, we obtain the expected number of the line-of-sight intersectionswith the H I galaxy images to be dn/dz~0.4, which does not contradictthe observed number of absorptions in QSO spectra.
| The origin of H I-deficiency in galaxies on the outskirts of the Virgo cluster. II. Companions and uncertainties in distances and deficiencies
The origin of the deficiency in neutral hydrogen of 13 spiral galaxieslying in the outskirts of the Virgo cluster is reassessed. If thesegalaxies have passed through the core of the cluster, their interstellargas should have been lost through ram pressure stripping by the hotX-ray emitting gas of the cluster. We analyze the positions of these HI-deficient and other spiral galaxies in velocity-distance plots, inwhich we include our compilation of velocity-distance data on 61elliptical galaxies, and compare with simulated velocity-distancediagrams obtained from cosmological N-body simulations. We find that20% relative Tully-Fisher distance errors are consistent with thegreat majority of the spirals, except for a small number of objectswhose positions in the velocity-distance diagram suggest grosslyincorrect distances, implying that the Tully-Fisher error distributionfunction has non-Gaussian wings. Moreover, we find that the distanceerrors may lead to an incorrect fitting of the Tolman-Bondi solutionthat can generate significant errors in the distance and especially themass estimates of the cluster. We suggest 4 possibilities for theoutlying H I-deficient spirals (in decreasing frequency): 1) they havelarge relative distance errors and are in fact close enough (atdistances between 12.7 and 20.9 Mpc from us) to the cluster to havepassed through its core and seen their gas removed by ram pressurestripping; 2) their gas is converted to stars by tidal interactions withother galaxies; 3) their gas is heated during recent mergers withsmaller galaxies; and 4) they are not truly H I-deficient (e.g. S0/amisclassified as Sa).Appendix A is only available in electronic form athttp://www.edpsciences.org
| 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.
| 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 UZC-SSRS2 Group Catalog
We apply a friends-of-friends algorithm to the combined Updated ZwickyCatalog and Southern Sky Redshift Survey to construct a catalog of 1168groups of galaxies; 411 of these groups have five or more members withinthe redshift survey. The group catalog covers 4.69 sr, and all groupsexceed the number density contrast threshold, δρ/ρ=80. Wedemonstrate that the groups catalog is homogeneous across the twounderlying redshift surveys; the catalog of groups and their membersthus provides a basis for other statistical studies of the large-scaledistribution of groups and their physical properties. The medianphysical properties of the groups are similar to those for groupsderived from independent surveys, including the ESO Key Programme andthe Las Campanas Redshift Survey. We include tables of groups and theirmembers.
| Total Magnitudes of Virgo Galaxies. I. Construction of a Self-Consistent Reference Dataset Spanning 8th to 18th Magnitude
The main objectives of this series of papers are: (1) to demonstrate theexistence of serious mutual disagreements between established total (andother integrated) magnitude scales for Virgo galaxies; (2) to attempt toquantify both the systematic and random errors present within thesemagnitude scales; (3) to investigate the origins of any large erroruncovered; and thereby (4) to encourage the general adoption of rigoroustotal-magnitude measurement procedures by the astronomical community.The ramifications of the findings presented in this series of paperswill be discussed in detail at a later date. In this paper, the first inthe series, a self-consistent dataset of trustworthy total-magnitudemeasurements is compiled for a sample of Virgo galaxies spanning a rangeof 10 000 in apparent brightness, based on only the most reliablemeasurements and photometry currently available. This reference dataset,which includes luminosity profile shape information, will be used insubsequent papers as one of the bases for assessing existing magnitudescales for Virgo galaxies. As most published magnitudes are based onB-band observations, this series of papers will also focus primarily onB-band measurements.
| A synthesis of data from fundamental plane and surface brightness fluctuation surveys
We perform a series of comparisons between distance-independentphotometric and spectroscopic properties used in the surface brightnessfluctuation (SBF) and fundamental plane (FP) methods of early-typegalaxy distance estimation. The data are taken from two recent surveys:the SBF Survey of Galaxy Distances and the Streaming Motions of AbellClusters (SMAC) FP survey. We derive a relation between(V-I)0 colour and Mg2 index using nearly 200galaxies and discuss implications for Galactic extinction estimates andearly-type galaxy stellar populations. We find that the reddenings fromSchlegel et al. for galaxies with E(B-V)>~0.2mag appear to beoverestimated by 5-10 per cent, but we do not find significant evidencefor large-scale dipole errors in the extinction map. In comparison withstellar population models having solar elemental abundance ratios, thegalaxies in our sample are generally too blue at a given Mg2;we ascribe this to the well-known enhancement of the α-elements inluminous early-type galaxies. We confirm a tight relation betweenstellar velocity dispersion σ and the SBF `fluctuation count'parameter N, which is a luminosity-weighted measure of the total numberof stars in a galaxy. The correlation between N and σ is eventighter than that between Mg2 and σ. Finally, we deriveFP photometric parameters for 280 galaxies from the SBF survey data set.Comparisons with external sources allow us to estimate the errors onthese parameters and derive the correction necessary to bring them on tothe SMAC system. The data are used in a forthcoming paper, whichcompares the distances derived from the FP and SBF methods.
| 2D modelling of the light distribution of early-type galaxies in a volume-limited sample - II. Results for real galaxies
In this paper we analyse the results of the two-dimensional (2D) fit ofthe light distribution of 73 early-type galaxies belonging to the Virgoand Fornax clusters, a sample volume- and magnitude-limited down toMB=-17.3, and highly homogeneous. In our previous paper(Paper I) we have presented the adopted 2D models of thesurface-brightness distribution - namely the r1/n and(r1/n+exp) models - we have discussed the main sources oferror affecting the structural parameters, and we have tested theability of the chosen minimization algorithm (MINUIT) in determining thefitting parameters using a sample of artificial galaxies. We show that,with the exception of 11 low-luminosity E galaxies, the best fit of thereal galaxy sample is always achieved with the two-component(r1/n+exp) model. The improvement in the χ2due to the addition of the exponential component is found to bestatistically significant. The best fit is obtained with the exponent nof the generalized r1/n Sersic law different from theclassical de Vaucouleurs value of 4. Nearly 42 per cent of the samplehave n<2, suggesting the presence of exponential `bulges' also inearly-type galaxies. 20 luminous E galaxies are fitted by thetwo-component model, with a small central exponential structure (`disc')and an outer big spheroid with n>4. We believe that this is probablydue to their resolved core. The resulting scalelengths Rh andRe of each component peak approximately at ~1 and ~2kpc,respectively, although with different variances in their distributions.The ratio Re/Rh peaks at ~0.5, a value typical fornormal lenticular galaxies. The first component, represented by ther1/n law, is probably made of two distinct families,`ordinary' and `bright', on the basis of their distribution in theμe-log(Re) plane, a result already suggested byCapaccioli, Caon and D'Onofrio. The bulges of spirals and S0 galaxiesbelong to the `ordinary' family, while the large spheroids of luminous Egalaxies form the `bright' family. The second component, represented bythe exponential law, also shows a wide distribution in theμ0c-log(Rh) plane. Small discs (orcores) have short scalelengths and high central surface brightness,while normal lenticulars and spiral galaxies generally have scalelengthshigher than 0.5kpc and central surface brightness brighter than20magarcsec-2 (in the B band). The scalelengths Reand Rh of the `bulge' and `disc' components are probablycorrelated, indicating that a self-regulating mechanism of galaxyformation may be at work. Alternatively, two regions of theRe-Rh plane are avoided by galaxies due todynamical instability effects. The bulge-to-disc (B/D) ratio seems tovary uniformly along the Hubble sequence, going from late-type spiralsto E galaxies. At the end of the sequence the ratio between the largespheroidal component and the small inner core can reach B/D~100.
| 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.
| 1.65 μm (H-band) surface photometry of galaxies. VII. Dwarf galaxies in the Virgo Cluster
We present near-infrared H-band (1.65 μm) observations and surfacebrightness profile decompositions for 75 faint (13.5 <~ mp<~ 18.5) galaxies, primarily taken among dwarf Ellipticals members ofthe Virgo cluster, with some Centaurus Cluster members, a BCD and twopeculiar galaxies taken as fillers. We model their surface brightnessprofiles with a de Vaucouleurs (D), exponential (E), mixed (bulge+diskor M) or truncated (T) law, and we derive for each galaxy the H bandeffective surface brightness (μe) and effective radius(re), the asymptotic total magnitude HT and thelight concentration index C31, defined as the ratio betweenthe radii that enclose 75% and 25% of the total light HT. Fora subsample we compare the NIR surface photometry with similar datataken in the B and V bands, and we give the B-H and B-V color profiles.Combining the present data with those previously obtained by our group(1157 objects) we analyze the NIR properties of a nearly completesample, representative of galaxies of all morphological types, spanning4 decades in luminosity. We confirm our earlier claim that the presenceof cusps and extended haloes in the light profiles (C31>5)is a strong, non-linear function of the total luminosity. We also findthat: i) among dE and dS0 galaxies D profiles are absent; 50% of thedecompositions are of type M, the remaining being of type E or T. ii)Less than 50% of the giant elliptical galaxies have pure D profiles, themajority being represented by M profiles. iii) Most giant galaxies (fromelliptical to Sb) have M profiles. iv) Most of late type spirals (Scd toBCD) have either E or T profiles. v) The type of decomposition is astrong function of the total H band luminosity, independent of theHubble classification: the fraction of type E decompositions decreaseswith increasing luminosity, while those of type M increase withluminosity. Pure D profiles are absent in the low luminosity rangeLH<1010 Lsolar and become dominantabove 1011 Lsolar, while T profiles are presentonly among low luminosity galaxies. vi) We find that dE-peculiargalaxies have structural parameters indistinguishable from those oflate-type dwarfs, thus they might represent the missing link between dEsand dIs. Based on observations taken with the ESO/NTT (ESO program64.N-0288), with the Telescopio Nazionale Galileo (TNG) operated on theisland of La Palma by the Centro Galileo Galilei of the CNAA at theSpanish Observatorio del Roque de los Muchachos of the IAC, with the SanPedro Martir 2.1~m telescope of the Observatorio Astronomico Nacional(OAN, Mexico), and with the OHP 1.2~m telescope, operated by the FrenchCNRS.
| 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.
| 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.
| A Complete Redshift Survey to the Zwicky Catalog Limit in a 2^h X 15 deg Region around 3C 273
We compile 1113 redshifts (648 new measurements, 465 from theliterature) for Zwicky catalog galaxies in the region (-3.5d <= delta<= 8.5d, 11h5 <= alpha <= 13h5). We include redshifts for 114component objects in 78 Zwicky catalog multiplets. The redshift surveyin this region is 99.5% complete to the Zwicky catalog limit, m_Zw =15.7. It is 99.9% complete to m_Zw = 15.5, the CfA Redshift Survey(CfA2) magnitude limit. The survey region is adjacent to the northernportion of CfA2, overlaps the northernmost slice of the Las CampanasRedshift Survey, includes the southern extent of the Virgo Cluster, andis roughly centered on the QSO 3C 273. As in other portions of theZwicky catalog, bright and faint galaxies trace the same large-scalestructure.
| Groups of galaxies. III. Some empirical characteristics.
Not Available
| 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.
| The SBF Survey of Galaxy Distances. I. Sample Selection, Photometric Calibration, and the Hubble Constant
We describe a program of surface brightness fluctuation (SBF)measurements for determining galaxy distances. This paper presents thephotometric calibration of our sample and of SBF in general. Basing ourzero point on observations of Cepheid variable stars, we find that theabsolute SBF magnitude in the Kron-Cousins I band correlates well withthe mean (V - I)0 color of a galaxy according to M barI=(-1.74+/-0.07)+(4.5+/-0.25)[(V-I)0-1.15] for 1.0< (V - I) < 1.3. This agrees well with theoretical estimates fromstellar population models. Comparisons between SBF distances and avariety of other estimators, including Cepheid variable stars, theplanetary nebula luminosity function (PNLF), Tully-Fisher (TF), Dn-sigma , SN II, and SN Ia, demonstrate that the calibration of SBF isuniversally valid and that SBF error estimates are accurate. The zeropoint given by Cepheids, PNLF, TF (both calibrated using Cepheids), andSN II is in units of megaparsecs; the zero point given by TF (referencedto a distant frame), Dn- sigma , and SN Ia is in terms of a Hubbleexpansion velocity expressed in km s-1. Tying together these two zeropoints yields a Hubble constant of H0=81+/-6 {km} {s}^{-1}{Mpc}^{-1} . As part of this analysis, we present SBF distances to 12nearby groups of galaxies where Cepheids, SN II, and SN Ia have beenobserved.
| 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.
| Morphological segregation of early-type galaxies in the Virgo cluster
We present evidence for a morphological segregation of early-typegalaxies with different isophote shapes in the Virgo cluster. Comparinglocal projected densities around galaxies, we find that, independentlyof their classification as elliptical or lenticular, galaxies with boxyisophotes are located in local density enhancements, while galaxies withdiscy isophotes lie in regions of lower local densities. Thissegregation is therefore not just the reflection of ordinarymorphological segregation between elliptical and lenticular galaxies,and it shows that the property of galaxies that is more sensitive to theenvironment is the presence or not of a stellar disc, rather than thebulge-to-disco ratio (and therefore the classification as an E or an S0galaxy).
| 'Global mapping' B-band photometry of a complete sample of Fornax and Virgo early-type galaxies
We present the B-band surface photometry of 19 early-type galaxies ofthe Virgo cluster, and of 28 galaxies of the same morphological typebelonging to the Fornax clusters, obtained through the `global mapping'technique which couples CCD and photographic plates. Taking into account33 galaxies already studied by Caon et al. (1990) with the samemethodology, the Virgo sample of early-type galaxies is now 80% completedown to B_T_=14. The Fornax sample is 95% complete down to B_T_=15. Thegeometric and photometric properties of the total sample of 80 galaxiesare derived measuring accurate light profiles, ellipticities, positionangles and Fourier coefficients of the isophotes. The main sources oferrors of the `global mapping' procedure are reviewed and the effects ofseeing discussed. Global galaxian parameters such as total luminosity,effective radius, and effective surface brightness, are computed for thewhole sample in a homogeneous way. Our goal is to create an unbiased setof data to be used for investigating the process of galaxy formation andevolution.
| Distribution of the spin vectors of the disk galaxies of the Virgo cluster. I. The catalogue of 310 disk galaxies in the Virgo area.
Not Available
| On the Shape of the Light Profiles of Early Type Galaxies
We have obtained the best fit to the light profiles of a luminosity-limited sample of elliptical and S0 galaxies with a power law r^1/n^,letting the exponent remain free rather than keeping it fixed at 1/n =1/4 as in the well-known de Vaucouleurs formula. The introduction of afree parameter in the fitting formula (ranging from n = 0.5 for (r_e_) =0.3 kpc to n = 16 for (r_e_) = 25 kpc) is justified by the existence ofa good correlation between n and the global galaxian parameters, such astotal luminosity and scale-radius. This result seems to be in line withthe segregation of properties between the `ordinary' and `bright'families of early-type galaxies, and has consequences for the claimedindependence of the shape of galaxy profiles with respect to theFundamental Plane parameters.
| A revised catalog of CfA1 galaxy groups in the Virgo/Great Attractor flow field
A new identification of groups and clusters in the CfA1 Catalog ofHuchra et al. is presented, using a percolation algorithm to identifydensity enhancements. It is shown that in the resulting catalog,contamination by interlopers is significantly reduced. The Schechterluminosity function is redetermined, including the Malmquist bias.
| 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.
| Far-infrared luminosity functions of normal galaxies
A volume-limited sample is constructed from the Zwicky catalog and IRASdata base to examine the FIR luminosity functions of normal galaxies,and to investigate possible relationships between FIR emission andgalaxy morphology. Quantitative and unbiased treatment is provided by'survival analysis' statistical methods. It is found that the FIRdistributions of normal galaxies are better fit by lognormal thanSchechter functions. The total FIR emissivity (8 to 115 microns) ofnormal galaxies is approximately equal to half their emission in the Bplus V optical bands. Normal galaxy FIR emission is uncorrelated withthe basic S0-Sm Hubble sequence of spiral galaxy morphology, but appearsto be affected by de Vaucouleurs' (1959) revised morphologicalclassifications based on inner rings and S-shaped arms. Spirals withbars and inner rings are systematically fainter than unbarred spirals.It is suggested that bars and rings reduce the amount or spatiallyconfine the dust in spiral disks, resulting in lower efficiencyconversion of optical and UV photons into the IR.
| Radio-continuum sources in nearby and bright E/S0 galaxies - Active nuclei versus star formation
Results of a sensitive VLA survey of nearby E/S0 galaxies are presented.The 204 galaxies surveyed, plus 12 additional galaxies with existing VLAimages, comprise a volume- and optical magnitude-limited sample. Thediscussion focuses on the relation between radio powers and opticalluminosities, whether the radio emission is driven by an active nucleusor by recent star formation, and what galaxian properties might enhancenuclear activity in an elliptical galaxy. It is suggested that the 67ellipticals in the sample should be targets of sensitive searches forHI, optical emission-line gas, and X-ray emitting gas.
| Radio-continuum sources in nearby and bright E/S0 galaxies - Sample selection and well-studied cases
A volume-limited sample of 216 nearby and optically bright E/S0 galaxieshas been compiled. Twelve of the galaxies are confirmed radio sourcesfor which VLA images are available. Most of the remaining galaxies havepowers less than or of the order of 10 to the 21st-22nd W/Hz, and thisinformation is used to establish the parameters of a new VLA survey ofthese galaxies. The basic optical properties of the galaxies in thesample are tabulated.
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