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Nearby early-type galaxies with ionized gas. I. Line-strength indices of the underlying stellar population
With the aim of building a data-set of spectral properties of wellstudied early-type galaxies showing emission lines, we presentintermediate resolution spectra of 50 galaxies in the nearby Universe.The sample, which covers several of the E and S0 morphologicalsub-classes, is biased toward objects that might be expected to haveongoing and recent star formation, at least in small amounts, because ofthe presence of the emission lines. The emission is expected to comefrom the combination of active galactic nuclei and star formationregions within the galaxies. Sample galaxies are located in environmentscorresponding to a broad range of local galaxy densities, althoughpredominantly in low density environments. Our long-slit spectra coverthe 3700-7250 Å wavelength range with a spectral resolution of≈7.6 Å at 5550 Å. The specific aim of this paper, and ourfirst step in the investigation, is to map the underlying galaxy stellarpopulation by measuring, along the slit positioned along the galaxymajor axis, line-strength indices at several, homogeneousgalacto-centric distances. For each object we extracted 7luminosity-weighted apertures (with radii 1.5´´,2.5´´, 10´´, r_e/10, r_e/8, r_e/4 and r_e/2)corrected for the galaxy ellipticity and 4 gradients (0 ≤ r ≤r_e/16, r_e/16 ≤ r ≤ r_e/8, r_e/8 ≤ r ≤ r_e/4 and r_e/4≤ r ≤ r_e/2). For each aperture and gradient we measured 25line-strength indices: 21 of the set defined by the Lick-IDS“standard” system (Trager et al. [CITE], ApJS, 116, 1) and 4introduced by Worthey & Ottaviani ([CITE], ApJS, 111, 377).Line-strength indices have been transformed to the Lick-IDS system.Indices derived then include Hβ, Mg1, Mg2, Mgb, MgFe, Fe5270,Fe5335 commonly used in classic index-index diagrams. The paperintroduces the sample, presents the observations, describes the datareduction procedures, the extraction of apertures and gradients, thedetermination and correction of the line-strength indices, the procedureadopted to transform them into the Lick-IDS System and the proceduresadopted for the emission correction. We finally discuss the comparisonsbetween our dataset and line-strength indices available in theliterature. A significant fraction, about 60%, of galaxies in thepresent sample has one previous measurement in the Lick-IDS system butbasically restricted within the r_e/8 region. Line-strength measuresobtained both from apertures and gradients outside this area and withinthe r_e/8 region, with the present radial mapping, are completely new.Full appendix and Figs. 8 to 13 are only available in electronic form athttp://www.edpsciences.org Full Tables 6, 7, 9 and 10 are only availableat the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/433/497 Based onobservations obtained at the European Southern Observatory, La Silla,Chile (Programs Nr. 60.A-0647 and 61.A-0406).
| The Aquarius Superclusters. II. Spectroscopic and Photometric Data
We present spectroscopic and photometric data for 920 galaxies selectedin 68 fields of the Aquarius Cluster Catalog. Typically, the 15brightest candidate members with magnitudes in the range16
| 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.
| Line-of-Sight Reddening Predictions: Zero Points, Accuracies, the Interstellar Medium, and the Stellar Populations of Elliptical Galaxies
Revised (B-V)0-Mg2 data, which are used to testreddening predictions, are presented for 402 elliptical galaxies. Thesereddening predictions can tell us both what the intrinsic errors are inthis relationship among gE galaxy stellar populations as well as detailsof nearby structure in the interstellar medium (ISM) of our Galaxy, andof the intrinsic errors in reddening predictions. Using least-squaresfits, the explicit 1 σ errors in reddenings predicted by theBurstein-Heiles (BH) method and the Schlegel and coworkers (IR) methodare calculated, as well as the 1 σ observational error in the(B-V)0-Mg2 for gE galaxies. It is found that indirections with E(B-V)<0.100 mag (where most of these galaxies lie),1 σ errors in the IR reddening predictions are 0.006-0.009 mag inE(B-V), those for BH reddening predictions are 0.011 mag, and the 1σ agreement between the two reddening predictions is 0.007 mag.The IR predictions have an accuracy of 0.010-0.011 mag in directionswith E(B-V)>=0.100 mag, significantly better than those of the BHpredictions (0.024-0.025). Both methods yield good evidence thatgas-to-dust variations that vary by a factor of 3, both high and low,exist along many lines of sight in our Galaxy. Both methods also predictmany directions with E(B-V)<0.015 mag, despite the difference in zeropoint that each has assumed. The ~0.02 higher reddening zero point inE(B-V) previously determined by Schlegel and coworkers is confirmed,primarily at the Galactic poles. Independent evidence of reddening atthe north Galactic pole (NGP) is reviewed, with the conclusion thatdirections still exist at the NGP that have E(B-V)<<0.01. Twolines of evidence suggest that IR reddenings are overpredicted indirections with high gas-to-dust ratios. As high gas-to-dust directionsin the ISM also include the Galactic poles, this overprediction is thelikely cause of the E(B-V)~0.02 mag larger IR reddening zero pointrelative to that of BH.
| 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
| Survey of the ISM in early-type galaxies. IV. The hot dust component
We present mid-IR photometric properties for a sample of 28 early-typegalaxies observed at 6.75, 9.63 and 15 mu m with the ISOCAM instrumenton board the ISO satellite. We find total mid-IR luminosities in therange (3-42) x 108 Lsun. The spectral energydistributions (SED) of the galaxies were derived using the mid-IR datatogether with previously published UV, optical and near-IR data. TheseSEDs clearly show a mid-IR emission coming from dust heated at T =~ 260K. Dust grains properties are inferred from the mid-IR colors. Themasses of the hot dust component are in the range 10-400Msun. The relationship between the masses derived from mid-IRobservations and those derived from visual extinction are discussed. Thepossible common heating source for the gas and dust is investigatedthrough the correlations between Hα and mid-IR luminosities. Basedon observations with ISO, an ESA project with instruments funded by ESAmember states (especially the PI countries: France, Germany, theNetherlands and the UK) and with participation of ISAS and NASA.
| 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 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
| A catalogue of Mg_2 indices of galaxies and globular clusters
We present a catalogue of published absorption-line Mg_2 indices ofgalaxies and globular clusters. The catalogue is maintained up-to-datein the HYPERCAT database. The measurements are listed together with thereferences to the articles where the data were published. A codeddescription of the observations is provided. The catalogue gathers 3541measurements for 1491 objects (galaxies or globular clusters) from 55datasets. Compiled raw data for 1060 galaxies are zero-point correctedand transformed to a homogeneous system. Tables 1, 3, and 4 areavailable in electronic form only at the CDS, Strasbourg, via anonymousftp 130.79.128.5. Table 2 is available both in text and electronic form.
| Total magnitude, radius, colour indices, colour gradients and photometric type of galaxies
We present a catalogue of aperture photometry of galaxies, in UBVRI,assembled from three different origins: (i) an update of the catalogueof Buta et al. (1995) (ii) published photometric profiles and (iii)aperture photometry performed on CCD images. We explored different setsof growth curves to fit these data: (i) The Sersic law, (ii) The net ofgrowth curves used for the preparation of the RC3 and (iii) A linearinterpolation between the de Vaucouleurs (r(1/4) ) and exponential laws.Finally we adopted the latter solution. Fitting these growth curves, wederive (1) the total magnitude, (2) the effective radius, (3) the colourindices and (4) gradients and (5) the photometric type of 5169 galaxies.The photometric type is defined to statistically match the revisedmorphologic type and parametrizes the shape of the growth curve. It iscoded from -9, for very concentrated galaxies, to +10, for diffusegalaxies. Based in part on observations collected at the Haute-ProvenceObservatory.
| A catalogue of spatially resolved kinematics of galaxies: Bibliography
We present a catalogue of galaxies for which spatially resolved data ontheir internal kinematics have been published; there is no a priorirestriction regarding their morphological type. The catalogue lists thereferences to the articles where the data are published, as well as acoded description of these data: observed emission or absorption lines,velocity or velocity dispersion, radial profile or 2D field, positionangle. Tables 1, 2, and 3 are proposed in electronic form only, and areavailable from the CDS, via anonymous ftp to cdsarc.u-strasbg.fr (to130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
| Metallicity Indices for Multi-Population Models.II.Bulges of Galaxies
We report metallicity indices in the Lick system (Hβ, Fe52, Fe53,NaD, Mg_2_) for a sample of 45 spiral bulges in the southern hemisphere.The velocity dispersion σ was also derived for each object. Spiralbulges and elliptical galaxies show a continuity in diagrams like theplane Mg_2_- or σ-Mg_2_. Using calibrations derived fromchemical evolutionary models, we estimated metallicities and abundanceratios for those bulges. The sample mean metallicity is [Fe/H]= -0.19+/- 0.27(rmsd), and the mean abundance ratios are [Mg/Fe] = 0.46 +/-0.11 (rmsd) and [Na/Fe] = 0.45 +/- 0.19(rmsd). These abundances suggestthat spiral bulges (like E's) were chemically enriched by type IIsupernovae, and that the main star formation era occurred in a timescale of the order of 1-2 Gyr.
| A survey of the ISM in early-type galaxies. I. The ionized gas.
We present results of a CCD optical imaging survey of the ionized gas in73 luminous elliptical and lenticular galaxies, selected from the RC3catalog to represent a broad variety of X-ray, radio, infrared andkinematical properties. For each galaxy we have used broad-band R imagesand narrow-band images centered at the Hα and [NII] emission linesto derive the luminosity and distribution of the ionized gas. We foundthat a large fraction of E (72%) and S0 (85%) galaxies in our samplecontain ionized gas. The gas morphology appears to be rather smooth formost galaxies; however ~12% of the sample galaxies show a very extendedfilamentary structure. According to the morphology and size of the gasdistribution, the galaxies have been classified into three broad groups,named small disk (SD), regular extended (RE) and filamentary structure(F). The mean diameter of the emitting region ranges between 1 and10kpc; the derived mass of the ionized gas ranges between 10^3^ and10^5^ solar masses. A significant correlation between Hα+[NII] andX-ray luminosities is found for those galaxies (27% of the sample) forwhich we have detected ionized gas and are also listed as X-ray sources.However, there are relatively strong X-ray emitting galaxies for whichwe have not detected Hα+[NII] emission and objects which showemission-lines but are not listed either in the EINSTEIN or in the ROSATdatabases. The distribution of datapoint and upper limits in thisdiagram suggests that galaxies with warm gas are also X-ray emitters,while there are X-ray emitters without measurable Hα+[NII]emission. Similar characteristics are present in the correlation betweenthe infrared luminosity in the 12 μm band and L_Hα+[NII]_;correlations with other infrared wavelengths are weaker. A strongcorrelation was also found between the Hα+[NII] luminosity and theluminosity in the B band inside the region occupied by the line-emittinggas. We use these correlations to discuss the possible mechanismsresponsible for the gas ionization and excitation, analyzing inparticular the role of the post-AGB stars and the thermal conductionfrom the X-ray halo in providing the necessary source of ionization.
| 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.
| Total and effective colors of 501 galaxies in the Cousins VRI photometric system
Total color indices (V-R)T, (V-I)T and effectivecolor indices (V-R)e, (V-I)e in the Cousins VRIphotometric system are presented for 501 mostly normal galaxies. Thecolors are computed using a procedure outlined in the Third ReferenceCatalogue of Bright Galaxies (RC3) whereby standard color curvesapproximated by Laplace-Gauss integrals are fitted to observedphotoelectric multiaperture photometry. 11 sources of such photometrywere used for our analysis, each source being assigned an appropriateweight according to a rigorous analysis of residuals of the data fromthe best-fitting standard color curves. Together with the integrated B-Vand U-B colors provided in RC3, our analysis widens the range ofwavelength of homogeneously defined colors of normal galaxies of allHubble types. We present color-color and color-type relations that canbe modeled to understand the star formation history of galaxies.
| 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.
| Photometrically distinct nuclei in elliptical and early-type disks galaxies.
Not Available
| 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.
| A search for dark matter in elliptical galaxies: Radially extended spectroscopic observations for six objects
Within the European Southern Observatory (ESO) Key Programme 'A searchfor dark matter in elliptical galaxies', we have performed a detailedstudy of the large scale stellar kinematics of NGC 1400, 4946, 5812,6721, 7507, and 7796. Our observations have produced kinematical datadown to the 24.1 mag/sq arcsec in the B band, i.e. in some cases out to2 Re and beyond. NGC 1400, 4946, and 6721 show significantrotation. The other three galaxies (NGC 5812, 7507, and 7796) can bedescribed by spherical non-rotating equilibrium models. For two of theseobjects self-consistent stellar dynamical models with constantmass-to-light ratio are found to give good fits to the photometric andkinematical data, although the presence of dark matter is not excluded.In contrast, NGC 7796 shows evidence for the presence of a dark halo.This galaxy also exhibits counterrotation inside 4 sec and,correspondingly, a central peak in the velocity dispersion profile. Onthe basis of the small sample of objects studied so far, with radiallyextended spectroscopic observations, possible trends in the size of darkhalos around elliptical galaxies are pointed out.
| The radial velocities of planetary nebulae in NGC 3379
We present the results of a radial velocity survey of planetary nebulae(PNs) in the normal elliptical galaxy NGC 3379 performed with the KittPeak 4 m telescope and the NESSIE multifiber spectrograph. In twohalf-nights, we measured 29 PNs with projected galactocentric distancesbetween 0.4 and 3.8 effective radii with an observational uncertainty ofabout 7 km/s. These data extend three times farther into the halo thanany previous absorption-line velocity study. The velocity dispersion andphotometric profile of the galaxy agrees extremely well with thatexpected from a constant mass-to-light ratio, isotropic orbit Jaffemodel with M/L(B) about 7; the best-fitting anisotropic models from aquadratic programming algorithm also give M/L(B) about 7. The data areconsistent with models that contain no dark matter within 3.5 effectiveradii of the galaxy's nucleus.
| Infrared emission and mass loss from evolved stars in elliptical galaxies
Small aperture 10.2-micron measurements of normal elliptical galaxiesshow that for almost all of these galaxies the 12-micron emission seenby IRAS is extended on the scale of the galaxy. NGC 1052 and NGC 3998are exceptions to this; much of their 10-12-micron emission comes fromthe inner regions of the galaxies and may be associated with theiractive nuclei, as is the case for many radio galaxies. The distributionof the IR light and the IR colors of elliptical galaxies suggest thatthe most plausible source of the 12-micron emission is photospheric andcircumstellear emission from cool evolved red giant stars. The 12-micronemission is well in excess of that expected from photospheric emissionalone; about 40 percent of it probably comes from circumstellar dust.
| Interstellar matter in early-type galaxies. I - The catalog
A catalog is given of the currently available measurements ofinterstellar matter in the 467 early-type galaxies listed in the secondedition of the Revised Shapley-Ames Catalog of Bright Galaxies. Themorphological type range is E, SO, and Sa. The ISM tracers are emissionin the following bands: IRAS 100 micron, X-ray, radio, neutral hydrogen,and carbon monoxide. Nearly two-thirds of the Es and SOs have beendetected in one or more of these tracers. Additional observed quantitiesthat are tabulated include: magnitude, colors, radial velocity, centralvelocity dispersion, maximum of the rotation curve, angular size, 60micron flux, and supernovae. Qualitative statements as to the presenceof dust or emission lines, when available in the literature, are given.Quantities derivative from the observed values are also listed andinclude masses of H I, CO, X-ray gas, and dust as well as an estimate ofthe total mass and mass-to-luminosity ratio of the individual galaxies.
| 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.
| The surface brightness test for the expansion of the universe. II - Radii, surface brightness, and absolute magnitude correlations for nearby E galaxies
Data for elliptical galaxies in the Virgo, Fornax, and Coma clusters andin the general field are analyzed in order to determine the dispersionin average surface brightness. The data are discussed using measures ofboth the effective radius and the Petrosian r(eta) radii. The dispersionis found to be about 0.5 mag after reducing the data to absolutemagnitude M(B) = -22. This value is smaller than the 1.8 mag Tolman (1 +z) exp 4 factor, even at the modest redshift of z = 0.5, showing thatthe Tolman test is feasible in practice as well as in principle.
| Low-luminosity radio sources in early-type galaxies
A sensitive radio continuum survey of 114 nearby E and S0 galaxies hasbeen made to search for weak sources. The radio detection rate is 42percent, with a flux limit of 0.8 mJy at 5 GHz. By deriving the radioluminosity function for a complete sample, it is shown that most brightearly-type galaxies have low-luminosity nonthermal radio sources.Galaxies of similar optical luminosity vary widely in radio luminosity,but a characteristic radio power rises roughly as the optical luminositysquared. S0 galaxies have weaker radio sources on average thanelliptical galaxies, but this can be explained by the low luminosity ofmost S0 bulges relative to ellipticals. No correlation is found betweenradio power and axial ratio for galaxies with radio luminosities below10 to the 23rd W/Hz.
| Revised supernova rates in Shapley-Ames galaxies
Observations of 855 Shapley Ames galaxies made from November 1, 1980 toOctober 31, 1988, together with improved supernova luminosities, havebeen used to derive the frequency of supernovae of different types, andthe results are presented in tables. From a uniform database of 24supernovae discovered, the following SN rates are found, expressed in SNper century per 10 to the 10th L(B)(solar): SN Ia, 0.3; SN Ib, 0.3; andSN II, 1.0. The present data confirm the relatively high frequency of SNII in late-type galaxies that has been found by many previousinvestigators.
| 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.
| UBVRI aperture photometry of early-type galaxies
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1988A&AS...72..215P&db_key=AST
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