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The fundamental plane of isolated early-type galaxies
Here we present new measurements of effective radii, surfacebrightnesses and internal velocity dispersions for 23 isolatedearly-type galaxies. The photometric properties are derived from newmulticolour imaging of ten galaxies, whereas the central kinematics forseven galaxies are taken from forthcoming work by Hau & Forbes.These are supplemented with data from the literature. We reproduce thecolour-magnitude and Kormendy relations and strengthen the result of therecent work of Reda et al. that isolated galaxies follow the samephotometric relations as galaxies in high-density environments. We alsofind that some isolated galaxies reveal fine structure indicative of arecent merger, while others appear undisturbed. We examine theFundamental Plane both in the traditional Re,μe, σ space and also in κ space. Most isolatedgalaxies follow the same Fundamental Plane tilt and scatter for galaxiesin high-density environments. However, a few galaxies notably deviatefrom the Plane in the sense of having smaller M/L ratios. This can beunderstood in terms of their younger stellar populations, which arepresumably induced by a gaseous merger. Overall, isolated galaxies havesimilar properties to those in groups and clusters with a slightenhancement in the frequency of recent mergers/interactions.
| The photometric properties of isolated early-type galaxies
Isolated galaxies are important because they probe the lowest densityregimes inhabited by galaxies. We define a sample of 36 nearby isolatedearly-type galaxies for further study. Our isolation criteria requirethem to have no comparable-mass neighbours within 2 B-band magnitudes,0.67 Mpc in the plane of the sky and 700 km s-1 in recessionvelocity. New wide-field optical imaging of 10 isolated galaxies withthe Anglo-Australian Telescope confirms their early-type morphology andrelative isolation. We also present imaging of four galaxy groups as acontrol sample. The isolated galaxies are shown to be moregravitationally isolated than the group galaxies. We find that theisolated early-type galaxies have a mean effective colour of(B-R)e= 1.54 +/- 0.14, similar to their high-densitycounterparts. They reveal a similar colour-magnitude relation slope andsmall intrinsic scatter to cluster ellipticals. They also follow theKormendy relation of surface brightness versus size for luminous clustergalaxies. Such properties suggest that the isolated galaxies formed at asimilar epoch to cluster galaxies, such that the bulk of their stars arevery old. However, our galaxy modelling reveals evidence for dust lanes,plumes, shells, boxy and disc isophotes in four out of nine galaxies.Thus at least some isolated galaxies have experienced a recentmerger/accretion event, which may have induced a small burst of starformation. We derive luminosity functions for the isolated galaxies andfind a faint slope of -1.2, which is similar to the `universal' slopefound in a wide variety of environments. We examine the number densitydistribution of galaxies in the field of the isolated galaxies. Only thevery faintest dwarf galaxies (MR>~-15.5) appear to beassociated with the isolated galaxies, whereas anyintermediate-luminosity galaxies appear to lie in the background.Finally, we discuss possible formation scenarios for isolated early-typegalaxies. Early epoch formation and a merger/accretion of galaxies arepossible explanations. The collapse of a large, virialized group is anunlikely explanation, but that of a poor group remains viable.
| 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
| A Test for Large-Scale Systematic Errors in Maps of Galactic Reddening
Accurate maps of Galactic reddening are important for a number ofapplications, such as mapping the peculiar velocity field in the nearbyuniverse. Of particular concern are systematic errors which vary slowlyas a function of position on the sky, as these would induce spuriousbulk flow. We have compared the reddenings of Burstein & Heiles (BH)and those of Schlegel, Finkbeiner, & Davis (SFD) to independentestimates of the reddening, for Galactic latitudes |b|>10^deg. Ourprimary source of Galactic reddening estimates comes from comparing thedifference between the observed B-V colors of early-type galaxies, andthe predicted B-V color determined from the B-V-Mg_2 relation. We havefitted a dipole to the residuals in order to look for large-scalesystematic deviations. There is marginal evidence for a dipolar residualin the comparison between the SFD maps and the observed early-typegalaxy reddenings. If this is due to an error in the SFD maps, then itcan be corrected with a small (13%) multiplicative dipole term. Weargue, however, that this difference is more likely to be due to a small(0.01 mag) systematic error in the measured B-V colors of the early-typegalaxies. This interpretation is supported by a smaller, independentdata set (globular cluster and RR Lyrae stars), which yields a resultinconsistent with the early-type galaxy residual dipole. BH reddeningsare found to have no significant systematic residuals, apart from theknown problem in the region 230^deg
| 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.
| Galaxy coordinates. II. Accurate equatorial coordinates for 17298 galaxies
Using images of the Digitized Sky Survey we measured coodinates for17298 galaxies having poorly defined coordinates. As a control, wemeasured with the same method 1522 galaxies having accurate coordinates.The comparison with our own measurements shows that the accuracy of themethod is about 6 arcsec on each axis (RA and DEC).
| Groups of galaxies. III. Some empirical characteristics.
Not Available
| 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.
| Photoelectric UBV Photometry of 179 Bright Galaxies
This paper presents photoelectric UBV multiaperture photometry of 179bright galaxies that was used to compute total magnitudes and colorindices published in the Third Reference Catalog of Bright Galaxies(RC3). The observations were made at the McDonald Observatory from 1983December to 1986 September with an Amperex 56-DVP photometer attached tothe 0.76 and 0.91 m telescopes. The observations can also be used tocalibrate CCD images.
| 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.
| 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.
| 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.
| Spectroscopy and photometry of elliptical galaxies. II - The spectroscopic parameters
Radial velocities, velocity dispersions, and Mg line-strength indicesare measured for 469 elliptical galaxies using four telescope/detectorconfigurations. The data have been put on a common scale; the scatter ofrepeat measurements indicates an uncertainty of + or - 10 percent and +or - 0.01 mag for single determinations of sigma and Mg2, respectively.A correction for the change in linear aperture size as a function ofdistance has been derived, and mean corrected values of sigma and Mg2are adopted. The galaxies have been assigned to groups by combining thepresent velocities with those in the redshift catalog of Huchra et al.(1983) and using the algorithm of Huchra and Geller (1982).
| Tidal triggering of Seyfert galaxies and quasars - Occurrence in multiple systems
An extension of earlier work which showed with computer models thatobserved companions for Seyferts are sufficient to induce gravitationalinstability in a disk galaxy is discussed. The instability leads to aninflow of matter into the nuclear region and possibly to Seyfertactivity. If selection effects have been properly taken into account,the fraction of Seyfert galaxies found in multiple systems is at leastthree quarters and possibly higher. Furthermore, the Hubble types of thefew isolated Seyferts are consistent with their being results of recentgalaxy mergers.
| A catalog of stellar velocity dispersions. I - Compilation and standard galaxies
A catalog of central stellar velocity dispersion measurements ispresented, current through June 1984. The catalog includes 1096measurements of 725 galaxies. A set of 51 standard galaxies is definedwhich consists of galaxies with at least three reliable, concordantmeasurements. It is suggested that future studies observed some of thesestandard galaxies in the course of their observations so that differentstudies can be normalized to the same system. Previous studies arecompared with the derived standards to determine relative accuracies andto compute scale factors where necessary.
| Mass-to-light ratio of elliptical galaxies
Two virial formulas, which take into account the observed flattening,are established for oblate ellipticals obeying the r to the 1/4th powerlaw and used to derive the mean mass to light ratios in their centralpart. One of them, which requires the knowledge of only one kinematicalparameter, the central (stellar) velocity dispersion, is applied to 197ellipticals. The other one, which uses in addition the maximum stellarrotation velocity, is shown to be less sensitive to the unknown trueflattenings and to possible velocity anisotropies. It is applied to 30ellipticals. Both methods give a mean blue mass to luminosity ratio ofabout 13, without any clear correlation with the absolute luminosity ofthe galaxy.
| A survey of galaxy redshifts. IV - The data
The complete list of the best available radial velocities for the 2401galaxies in the merged Zwicky-Nilson catalog brighter than 14.5mz and with b (II) above +40 deg or below -30 deg ispresented. Almost 60 percent of the redshifts are from the CfA surveyand are accurate to typically 35 km/s.
| A catalog of hierarchical subclustering in the Turner-Gott groups
Information on the substructure, to four levels of hierarchy, ispresented for the 103 groups listed by Turner and Gott (TG) in theircatalog of groups of galaxies. All galaxies brighter than Mpg= 14.0 in the region delta is 0 deg or greater and b(II) is 40 deg orgreater that have been assigned group memberships by TG are included.Also listed is the local environmental information for each of thegalaxies, giving the surface density enhancement beta in the galaxy'sneighborhood, calculated at 15 levels in the range beta = 4.6 to 10,000.
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