Садржај
Слике
Уплоадјуј своје слике
DSS Images Other Images
Везани чланци
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
| Evolution and surface abundances of red giants experiencing deep mixing
We have calculated the evolution of low metallicity red giant starsunder the assumption of deep mixing between the convective envelope andthe hydrogen burning shell. We find that the extent of the observedabundance anomalies, and in particular the universal O-Naanticorrelation, can be totally explained by mixing which does not leadto significant helium enrichment of the envelope. On the other hand,models with extremely deep mixing and strong helium enrichment predictanomalies of sodium and oxygen, which are much larger than the observedones. This latter result depends solely on the nucleosynthesis insidethe hydrogen burning shell, but not on the details of the mixingdescriptions. These, however, influence the evolution of surfaceabundances with brightness, which we compare with the limitedobservational material available. Our models allow, nevertheless, toinfer details on the depth and speed of the mixing process in severalclusters. Models with strong helium enrichment evolve to highluminosities and show an increased mass loss. However, under peculiarassumptions, red giants reach very high luminosities even withoutextreme helium mixing. Due to the consequently increased mass loss, suchmodels could be candidates for blue horizontal branch stars, and, at thesame time, would be consistent with the observed abundance anomalies.
| 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.
| 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.
| Candidates for a southern extension of the Karachentsev catalogue of isolated pairs of galaxies.
Not Available
| 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.
| Parsecscale Radio Cores in Early Type Galaxies
We find compact (<0.03 arcsec) radio-continuum cores in about 70 percent of radio-emitting elliptical and S0 galaxies over a wide range intotal radio power (10^21^-,10^26^ W Hz^-1^ at 5 GHz). The cores usuallyhave a flat or rising spectrum between 2.3 and 8.4 GHz, with a medianspectral index of + 0.3. Even at low luminosities, the radio emissionfrom most elliptical galaxies appears to be powered by a parsec-scale`engine' like those in classical radio galaxies and quasars. The coreand total radio power are related (P_core_ is proportional toP_total_^0.7^ on average), and the parsec-scale cores of radio galaxiesare typically one hundred times more powerful than those in `normal'giant elliptical galaxies.
| 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.
| 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.
| Long-Baseline Interferometry of a Complete Southern Sample of Early-Type Galaxies
Not Available
| 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.
| A catalog of southern groups of galaxies
A catalog of groups of galaxies identified in the southern Galactic capis presented. This catalog was constructed utilizing the group-findingalgorithm developed by Huchra and Geller (1982) to analyze galaxysamples with well-defined selection criteria and complete velocityinformation.
| 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.
| Surface photometry of southern elliptical galaxies
The results of a surface photometry survey for 131 elliptical galaxiesin the southern hemisphere are presented. In this paper isophotal mapsand major-axis profiles are shown, deriving for each galaxy in thesample structural parameters using the de Vaucouleurs law as usefulparametric descriptor of the light distribution of elliptical galaxies.
| The local radio luminosity function of galaxies at 843 MHz
Two independent samples of galaxies have been observed with the MolongloObservatory Synthesis Telescope at 843 MHz, and the resulting localradio luminosity function (LRLF) has been extended to radio powers ofabout 10 to the 18th W/Hz per sr. E and S0 galaxies are found to beunimportant to the LRLF at low radio luminosities, but to behave likestandard candles above powers of about 10 exp 22.5 W/Hz per sr. Theobservations suggest that the radio properties of the most massive S0galaxies resemble those of radio ellipticals, while at lowerluminosities the detection rate and radio-optical correlation arecomparable to those of early-type spirals.
| 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).
| Planetary nebulae and galactic temperature gradient.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1986RMxAA..12..249M&db_key=AST
| BV photometry of southern elliptical galaxies
Photometric data for 78 elliptical galaxies observed in V and B colorswith the Cerro Tololo Inter-American Observatory 0.9-m telescope duringApril and November 1983 are examined. Lamberts' data from the ESO surveyof the ESO (B) Atlas are presented. The data are analyzed in order tostudy the motion of the Local Group and the spatial distribution ofgalaxies in the local region of the universe. The photometric data arecompared to the data in the photometry catalog of Longo and deVaucouleurs (1983, 1985) and good correlation between the observationsis detected.
| Ionized gas in elliptical and S0 galaxies. I - A survey for H-alpha and forbidden N II emission
A spectroscopic survey of a large sample of southern E and S0 galaxiesin order to detect ionized gas in the nuclei is reported. The strongestline in the 6000-7000 A range was nearly always forbidden N II 6584 A,followed by H-alpha and forbidden S II 6716, 6731 A. Identical detectionrates of about 50 percent were obtained for the forbidden N II line inboth E and S0 galaxies. The mass of ionized gas in early-type galaxieswas very small, with values typically in the range 1000-10,000 solarmasses. The relative emission-line strengths in virtually every casewere indistinguishable from those of LINER nuclei. The observed valuesof the forbidden N II 6584 A/H-alpha ratios fell mostly between one andthree and seem correlated with galaxy absolute magnitude. The existenceof such a correlation may be indicative of metallicity differences.
| Southern Galaxy Catalogue.
Not Available
| Redshifts for 228 southern galaxies
In this paper, new redshifts are presented for 228 galaxies locatedsouth of declination -30 deg. The observations were made with aphoton-counting Reticon detector on the Observatorio Nacional (ON)60-in. telescope. The detector is identical to the one used at MountHopkins for the CfA Redshift Survey, and the redshifts were derivedusing the same data-analysis system. A preliminary comparison withpublished 21-cm redshifts indicates that the velocities have azero-point offset of about -4 km/s, with a typical uncertainty of 40km/s. The observations reported here are the initial results of theON-CfA Redshift Survey currently being undertaken in the southernhemisphere.
| Radio and optical observations of a complete sample of E and SO galaxies. III. A radio continuum survey at 2.7 and 5.0 GHz.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984AJ.....89...53S&db_key=AST
| Radio and optical observations of a complete sample of E and SO galaxies. II. UBV aperture photometry.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984AJ.....89...34S&db_key=AST
|
Додај нови чланак
Линкови у сродству са темом
Додај нови линк
Чланови следећих група \:
|
Посматрања и Астрометриски подаци
Каталог и designations:
|
