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BUDDA: A New Two-dimensional Bulge/Disk Decomposition Code for Detailed Structural Analysis of Galaxies
We present BUDDA (Bulge/Disk Decomposition Analysis), a new code devotedto perform a two-dimensional bulge/disk decomposition directly from theimages of galaxies. The bulge component is fitted with a generalizedSérsic profile, whereas disks have an exponential profile. Noother components are included. Bars and other substructures, likelenses, rings, inner bars, and inner disks, are studied with theresidual images obtained through the subtraction of bulges and disksfrom the original images. This means that a detailed structural analysisof galaxies may be performed with a small number of parameters, andsubstructures may be directly studied with no a priori assumptions. Ashas been already shown by several studies, two-dimensional fitting ismuch more reliable than one-dimensional profile fitting. Moreover, ourcode has been thoroughly tested with artificial data, and we demonstrateit to be an accurate tool for determining structural parameters ofgalaxies. We also show that our code is useful in various kinds ofstudies, including galaxies of, e.g., different morphological types, andinclinations, which also may be observed at different spatialresolutions. Thus, the code has a broader range of potentialapplications than most of the previous codes, which are developed totackle specific problems. To illustrate its usefulness, we present theresults obtained with a sample of 51 mostly early-type galaxies (butcovering the whole Hubble sequence). These results show some of theapplications in which the code may be used: the determination ofparameters for fundamental plane and structural studies, quantitativemorphological classification of galaxies, and the identification andstudy of hidden substructures. We have determined the structuralparameters of the galaxies in our sample and found many examples ofhidden inner disks in ellipticals, secondary bars, nuclear rings anddust lanes in lenticulars and spirals, and also wrong morphologicalclassification cases. We now make BUDDA generally available to theastronomical community.Based on observations made at the Pico dos Dias Observatory(PDO/LNA-CNPq), Brazil.
| 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
| Line-strength indices and velocity dispersions for 148 early-type galaxies in different environments
We have derived high quality line-strength indices and velocitydispersions for a sample of 148 early-type galaxies in differentenvironments. The wavelength region covered by the observations (lambda=~ 4600 to 6600 Å) includes the Lick/IDS indices Hβ,Mg1, Mg2, Mgb, Fe5015, Fe5270, Fe5335, Fe5406,Fe5709, Fe5782, NaD, TiO1 and TiO2. The data areintended to address possible differences of the stellar populations ofearly-type galaxies in low- and high-density environments. This paperdescribes the sample properties, explains the data reduction andpresents the complete list of all the measurements. Most galaxies of thesample (85%) had no previous measurements of any Lick/IDS indices andfor 30% of the galaxies we present first-time determinations of theirvelocity dispersions. Special care is taken to identify galaxies withemission lines. We found that 62 per cent of the galaxies in the samplehave emission lines, as measured by the equivalent width of the [OIII]5007Å line, EW[OIII] > 0.3 Å. Tables 5 and 6 are onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/ A+A/395/431. They are also available via ftp atftp.mpe.mpg.de in the directory people/dthomas/Beuing02 or via WWW atftp://ftp.mpe.mpg.de/people/dthomas/Beuing02.
| Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
In this paper we describe the Nearby Optical Galaxy (NOG) sample, whichis a complete, distance-limited (cz<=6000 km s-1) andmagnitude-limited (B<=14) sample of ~7000 optical galaxies. Thesample covers 2/3 (8.27 sr) of the sky (|b|>20deg) andappears to have a good completeness in redshift (97%). We select thesample on the basis of homogenized corrected total blue magnitudes inorder to minimize systematic effects in galaxy sampling. We identify thegroups in this sample by means of both the hierarchical and thepercolation ``friends-of-friends'' methods. The resulting catalogs ofloose groups appear to be similar and are among the largest catalogs ofgroups currently available. Most of the NOG galaxies (~60%) are found tobe members of galaxy pairs (~580 pairs for a total of ~15% of objects)or groups with at least three members (~500 groups for a total of ~45%of objects). About 40% of galaxies are left ungrouped (field galaxies).We illustrate the main features of the NOG galaxy distribution. Comparedto previous optical and IRAS galaxy samples, the NOG provides a densersampling of the galaxy distribution in the nearby universe. Given itslarge sky coverage, the identification of groups, and its high-densitysampling, the NOG is suited to the analysis of the galaxy density fieldof the nearby universe, especially on small scales.
| A 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.
| 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.
| UBVRI photoelectric photometry of bright southern early-type galaxies
UBVRI multi-aperture photometry of 207 bright southern galaxies and of72 objects of an additional list is presented. These observations weremade for obtaining the magnitude scale zero-point as an accuratedetermination of the sky background for a two-dimensional photometryprogram concerning these galaxies. We have also inferred the asymptoticmagnitudes, color indices and effective apertures of these objects. Ourresults are in good agreement with those of others authors.
| 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.
| 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.
| The supergalactic plane redshift survey
Redshift measurements, about 1000 of which are new, are presented for1314 galaxies in a survey toward the apex of the large-scale streamingflow for ellipticals. The velocity histogram shows that the excess ingalaxy number counts in this area is due to a substantial concentrationof galaxies with discrete peaks at V about 3000 km/s and V about 4500km/s. After correction for the sampling function, the centroid of thedensity distribution is found to be near V about 4500 km/s.Normalization to the more extensive SSRS survey, which was selected bythe same criteria, shows that the region studied contains a considerableoverdensity of galaxies from 2000 to 6000 km/s. This result is in goodagreement with the 'great attractor' model suggested by Lynden-Bell etal. (1988) which attributes the peculiar motions of elliptical galaxiesover a large region of space to an extensive mass overdensity whichincludes the Hydra-Centaurus and Pavo-Indus superclusters. The centroidof the density enhancement is also consistent with new data by Dresslerand Faber (1990) of peculiar motions of elliptical and spiral galaxies,both of which show a zero crossing of the Hubble line at approximately4500-5000 km/s.
| New velocity dispersions and photometry for E and S0 galaxies in the great attractor
New spectroscopy and photometry have been obtained for 136 ellipticaland S0 galaxies in the direction of the large-scale streaming flowattributed to the great attractor. Measurements of central velocitydispersion (sigma), total B magnitudes B(T), the photometric parameterDn, and the absorption-line index Mg2 are presented. Both internal andexternal comparisons indicate that measurements of log sigma areaccurate to 0.05 dex, B(T) to 0.15 mag, Dn to 0.015 dex, and Mg2 to0.017 mag. These data have been used by Dressler and Faber (1990) toestimate distances for these galaxies via the Dn-sigma relation. It isshown in this paper that the Dn-Mg2 relation also predicts the sametrends of peculiar velocity with distance, but with less accuracy. Therelative accuracy of other distance indicators for elliptical galaxiesis also discussed.
| 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.
| A catalogue of early-type galaxies with emission lines
Spectroscopic and photometric data on 289 early-type galaxies (E and S0)with optical emission lines are presented and possible correlationsamong properties of the galaxies in the sample are investigated. Theoccurrence of phenomena as radio emission, presence of neutral hydrogenand dust shows an increase in comparison with the occurrence of the samephenomena in these morphological classes as a whole. There is noevidence of a relationship between apparent shape and presence ofionized gas in the central regions.
| Southern Galaxy Catalogue.
Not Available
| A survey of O II forbidden line emission in elliptical galaxies
A survey of elliptical galaxy spectra using image-tube spectrograms hasbeen carried out with the result that 40 percent of the galaxies havebeen found to contain ionized gas. Galaxies with intense nuclearemission also tend to have extended emission that appears to be confinedto a plane. Since there is a detectable velocity gradient for the gas inthose planes, the gas appears to be in a rotating disk.
| A comparison of distance scales for early-type galaxies
The distance scales of elliptical and lenticular galaxies areintercompared, based on the velocity dispersion indicator derived from arevised Faber-Jackson relation. The scales are found to be in nearperfect agreement with scales derived from the luminosity index and fromthe 21 cm line width indicator. The scales are also in excellentagreement with the distance scale derived by Michard (1979). Additionsare offered for the general catalog of 424 early-type galaxies, and aseries of reduction equations is presented which reduces the externalerrors in the distance moduli.
| 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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