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|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.
|High-resolution radio observations of Seyfert galaxies in the extended 12-μm sample - II. The properties of compact radio components|
We discuss the properties of compact nuclear radio components in Seyfertgalaxies from the extended 12-μm AGN sample of Rush et al. Our mainresults can be summarized as follows. Type 1 and type 2 Seyferts producecompact radio components which are indistinguishable in strength andaspect, indicating that their central engines are alike, as proposed bythe unification model. Infrared IRAS fluxes are more closely correlatedwith low-resolution radio fluxes than high-resolution radio fluxes,suggesting that they are dominated by kiloparsec-scale, extranuclearemission regions; extranuclear emission may be stronger in type 2Seyferts. Early-type Seyfert galaxies tend to have stronger nuclearradio emission than late-type Seyfert galaxies. V-shaped extendedemission-line regions, indicative of `ionization cones', are usuallyfound in sources with large, collimated radio outflows. Hidden broadlines are most likely to be found in sources with powerful nuclear radiosources. Type 1 and type 2 Seyferts selected by their IRAS 12-μm fluxdensities have well-matched properties.
|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.
|Optical Spectroscopic Properties of a Sample of Interacting Galaxies|
We present spectroscopic observations of 83 galaxies from a sample of 49pairs of optically selected interacting galaxies, most of thempreviously unobserved. These pairs consist of a main galaxy (componentA) and a companion (component B) that has about half or less thediameter of component A. From our spectra we determine that 27 galaxiesform truly physical pairs and seven are apparent pairs, for theremaining pairs we could only extract the spectra of the A components.The spectra of the physical pairs were classified into four groupsaccording to the emission-line spectra observed in each component. Theseclassifications were made because the sample exhibits a very large rangeof spectral properties, ranging from well-evolved stellar populations(older than 200 Myr) to emission-line--dominated starburst systems (80Myr or younger). In general terms, these spectral types are wellcorrelated with the morphological types of the galaxies. However, wefind no evidence of correlation of the equivalent width of H alpha + [NII] emission lines with the degree of the interaction or with the blueabsolute magnitude of the components. From the data it is alsodetermined that the average EW(H alpha + [N II]) for the physical pairsis 37 A for the A components and 54 A for the B components. For thegalaxies that form apparent pairs we obtain EW(H alpha + [N II]) = 27 A,confirming that physical pairs have higher mean star formation ratesthan isolated galaxies. This enhancement of the star formation activityis more likely to take place in both galaxies, but the strength of theactivity seems to be higher in the B components. The mean observedvalues of EW(H alpha + [N II]) are comparable with those observed in asample of strongly interacting or merging galaxies. On the other hand,we do not find the excess of Seyfert-type nuclei previously reported instudies of similar samples of galaxies.
|Dust in the Cores of Early-Type Galaxies|
The dust properties of all early-type galaxies imaged with the PlanetaryCamera of the Hubble Space Telescope in cycles I-III are examined. Dustis detected in 31 out of 64 galaxies, although the sample is biasedagainst the detection of dust. From the distribution of observed axisratios of the dust features it is inferred that 78% +/- 16% ofearly-type galaxies contain nuclear dust. The detection rate in radiogalaxies is higher (72% +/- 16%) than in radio-quiet galaxies(33%+/-9%). In radio galaxies with double radio structure, the dust isusually found perpendicular to the radio axis. Dust masses range from10^3^-10^7^ solar masses. From the dependence of the misalignment angle(the angle between dust major axis and galaxy major axis) on size andappearance of the dust, it is found that dust features withsemimajor-axis size a_d_ > 250 pc are generally not settled. If it isassumed that dust lanes with a_d_ <250 pc are in equilibrium in thegalaxy potential, the observed distribution of misalignment angles canonly be explained if elliptical galaxies have a mean triaxiality >= 0.4. The best fit is obtained for = 0.8,higher than values derived through other methods. This difference cannotbe explained by a dependence of on radius. Therefore, it seemsdust is not always completely relaxed, even on the smallest scales.Furthermore, the rotation axis of the dust does not generally coincidewith that of the stars. This seems to suggest that the dust is acquiredfrom outside, and has some way of losing its angular momentumefficiently.
|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.
|Galaxy properties in different environments. 1: The sample|
This paper presents two galaxy samples, respectively in a high and in alow local density environments, that were generated from the SouthernSky Redshift Survey (SSRS) catalog using objective criteria. Apreliminary comparison of physical properties in these two samplesreveals that galaxies in high-density environments tend to be under ahigher starbursting activity, have a deficiency of the neutral hydrogencontent, present a higher fractional Seyfert population and a higherfraction of barred spirals as well. The present samples are intended tobe used in future spectroscopic observations for more detailedinvestigation.
|Southern Sky Redshift Survey - The catalog|
The catalog of radial velocities for galaxies which comprise thediameter-limited sample of the Southern Sky Redshift Survey ispresented. It consolidates the data of observations carried out at theLas Campanas Observatory, Observatorio Nacional, and South AfricanAstronomical Observatory. The criteria used for the sample selection aredescribed, as well as the observational procedures and the techniqueutilized to obtain the final radial velocities. The intercomparisonbetween radial velocity measurements from different telescopes indicatesthat the final data base is fairly homogeneous with a typical error ofabout 40 km/s. The sample is at present 90 percent complete, and themissing galaxies are predominantly objects with very low surfacebrightness for which it is very difficult to obtain optical redshifts.
|The plane W(Na I) X W(Mg I) - Effects of interstellar Na I in a sample of southern galaxies|
Galaxy spectra from a subsample of the Southern Sky Redshift Survey databank were used to study the equivalent width plane for the lines Na Ilambda 5893 A vs Mg I lambda 5175 A. An estimate of how important thecontribution of the interstellar gas for the sodium line is compared tothat of the stellar population. The sample is made up of galaxies withmorphological types from E to Sc and are distributed up to radialvelocities of 25,000 km/s, most of them smaller than 15,000 km/s. Mostearly type galaxies with dust lanes, particularly nearly edge-on So's,present an enhancement of the Na I line. Inclined spiral galaxies tendto present enhanced Na I with respect to face-on spirals. This tendency,previously found in a smaller sample of galaxies limited to V equal toor less than 6000 km/s, is now confirmed for more distant ones. In thelarge velocity sample it shows the global bulge rather than the verynucleus; the persistence of the effect suggests that the scale height ofthe gas layer in the central disk can reach a considerable fraction ofthe bulge radius.
|A two-dimensional sheet of galaxies between two southern voids|
The question of examining real data for possible interconnectionsbetween voids has prompted the discovery of a striking two-dimensionalsheet of galaxies (including NGC and ESO galaxies) forming the interfaceto voids in Eridanus and Sculptor. A void is defined in terms of itsemptiness, and it is noted that structures revealed using all availableredshifts, south of declination -17.5 deg, agree with those found incontrolled surveys, that is voids are void of all galaxies, regardlessof luminosity, size, or type. Using casement displays, a significantoverdensity, or wall, of galaxies, some 650 km/s thick, approximately2000 x 2000 km/s wide is found forming the interface to Sculptor andEridanus.
|A southern redshift survey. I - Accurate redshifts for 500 galaxies observed at SAAO|
Radial velocities are presented for about 500 galaxies observed with anintensified Reticon photon-counting detector attached to the 1.9 mtelescope at the Sutherland field station of SAAO. The velocities weredetermined by cross correlation with standard velocity templates, fromthe measured wavelengths of emission lines, or from both techniques,with spectra covering the wavelength range from 3700 to 5400 A. Thefinal velocities appear to have the same zero point as H I radiovelocities, and have standard deviations of the order of 35 km/s, thoughcross-correlation velocities on their own may have significantly largererrors.
|The ON-CfA redshift survey of the southern hemisphere|
A redshift survey of a diameter-limited sample of southern galaxies hasbeen performed by the Observatorio Nacional in collaboration with theHarvard-Smithsonian Center for Astrophysics. Redshift data are presentedfor 442 galaxies. A relatively small mean difference of -5.2 km/s wasfound between the present redshifts and previous radio data.
|UBVRI photoelectric photometry of 191 southern galaxies|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984A&AS...58..249L&db_key=AST
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