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|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.
|21 CM H1 Line Spectra of Galaxies in Nearby Clusters|
A compilation of HI line fluxes, systemic velocities and line widths ispresented for \Ndet detected galaxies, mostly in the vicinities of 30nearby rich clusters out to a redshift of z ~ .04, specifically for usein applications of the Tully-Fisher distance method. New 21 cm HI lineprofiles have been obtained for ~ 500 galaxies in 27 Abell clustersvisible from Arecibo. Upper limits are also presented for \Nnod galaxiesfor which HI emission was not detected. In order to provide ahomogeneous line width determination optimized for Tully-Fisher studies,these new data are supplemented by the reanalysis of previouslypublished spectra obtained both at Arecibo and Green Bank that areavailable in a digital archive. Corrections for instrumental broadening,smoothing, signal-to-noise and profile shape are applied, and anestimate of the error on the width is given. When corrected forturbulent broadening and viewing angle, the corrected velocity widthspresented here will provide the appropriate line width parameter neededto derive distances via the Tully-Fisher relation.
|An image database. II. Catalogue between δ=-30deg and δ=70deg.|
A preliminary list of 68.040 galaxies was built from extraction of35.841 digitized images of the Palomar Sky Survey (Paper I). For eachgalaxy, the basic parameters are obtained: coordinates, diameter, axisratio, total magnitude, position angle. On this preliminary list, weapply severe selection rules to get a catalog of 28.000 galaxies, wellidentified and well documented. For each parameter, a comparison is madewith standard measurements. The accuracy of the raw photometricparameters is quite good despite of the simplicity of the method.Without any local correction, the standard error on the total magnitudeis about 0.5 magnitude up to a total magnitude of B_T_=17. Significantsecondary effects are detected concerning the magnitudes: distance toplate center effect and air-mass effect.
|Recalibration of the H-0.5 magnitudes of spiral galaxies|
The H-magnitude aperture data published by the Aaronson et al.collaboration over a 10 year period is collected into a homogeneous dataset of 1731 observations of 665 galaxies. Ninety-six percent of thesegalaxies have isophotal diameters and axial ratios determined by theThird Reference Cataloque of Bright Galaxies (RC3; de Vaucouleurs et al.1991), the most self-consistent set of optical data currently available.The precepts governing the optical data in the RC3 are systematicallydifferent from those of the Second Reference Catalogue (de Vaucouleurs,de Vaucouleurs, & Corwin 1976), which were used by Aaronson et al.for their original analyses of galaxy peculiar motions. This in turnleads to systematic differences in growth curves and fiducialH-magnitudes, prompting the present recalibration of the near-infraredTully-Fisher relationship. New optically normalized H-magnitude growthcurves are defined for galaxies of types SO to Im, from which new valuesof fiducial H-magnitudes, Hg-0.5, are measured forthe 665 galaxies. A series of internal tests show that these fourstandard growth curves are defined to an accuracy of 0.05 mag over theinterval -1.5 less than or equal to log (A/Dg) less than orequal to -0.2. Comparisons with the Aaronson et al. values of diameters,axial ratios, and fiducial H-magnitudes show the expected differences,given the different definitions of these parameters. The values ofHg-0.5 are assigned quality indices: a qualityvalue of 1 indicates an accuracy of less than 0.2 mag, quality 2indicates an accuracy of 0.2-0.35 mag, and quality 3 indicates anaccuracy of more than 0.35 mag. Revised values of corrected H I velocitywidths are also given, based on the new set of axial ratios defiend bythe RC3.
|The photoionization mechanism of LINERs - Stellar and nonstellar|
We present high quality spectroscopic observations of a sample of 14LINERs. Starlight removal is achieved by the subtraction of a suitableabsorption-line 'template' galaxy, allowing accurate measurements ofemission lines. We use these line fluxes to examine the possibleexcitation mechanisms of LINERs. We suggest that LINERs with weakforbidden O I 6300-A emission may be H II regions photoionized byunusually hot O-type stars. LINERs with forbidden O I/H-alphaapproximately greater than 1/6 may be powered by photoionization from anonstellar continuum. This is supported by the detection of broadH-alpha emission, a correlation between line width and critical density,and pointlike X-ray emission in several of these objects.
|The LINERs revisited|
The present consideration of the source of energy of low-ionizationnuclear emission-line regions (LINERs) proceeds by analyzing a largesample of objects; the emission line ratios thus obtained are comparedto theoretical values from photoionization models, which either includeor exclude the effect of relativistic electrons, and from shock models.It is found that the standard, optically thick photoionization modelscannot describe the entire range of observed line ratios, even in thecase where clouds of different densities are present. A more accuratecharacterization of LINERs must encompass the distribution of shocksand/or relativistic particles.
|A statistical study of properties of Seyfert and starburst galaxies|
Spectral and morphological data for 282 Seyfert and emission-linegalaxies spanning radio to X-ray wavelengths are compiled. The datainclude a large number of optical emission-line measurements which havenot been reported previously. These data are intended to provide aconvenient summary of the relevant properties of these galaxies, as wellas a data base to search for correlations among the various parametersin order to obtain a better understanding of the active galaxyphenomenon. The paper presents the data and analyzes the distributionsof various properties of Seyfert 1 and Seyfert 2 galaxies and starburstgalaxies. It is found that Seyferts 2s have a higher 60 micron/forbiddenO III 5007 A flux ratio than Seyfert 1s. This result, combined with thefact that Seyfert 2s are more heavily reddened, indicate that they havea higher dust content. It is also found that starburst nuclei arecomparable to Seyfert 2s in far-infrared and 20 cm luminosities,although their optical spectra are markedly different.
|Spectral classification of emission-line galaxies|
A revised method of classification of narrow-line active galaxies and HII region-like galaxies is proposed. It involves the line ratios whichtake full advantage of the physical distinction between the two types ofobjects and minimize the effects of reddening correction and errors inthe flux calibration. Large sets of internally consistent data are used,including new, previously unpublished measurements. Predictions ofrecent photoionization models by power-law spectra and by hot stars arecompared with the observations. The classification is based on theobservational data interpreted on the basis of these models.
|A distance scale from the infrared magnitude/H I velocity-width relations. V - Distance moduli to 10 galaxy clusters, and positive detection of bulk supercluster motion toward the microwave anisotropy|
The IR/H I relation is employed to derive relative distances to 10nearby galaxy clusters. A problem originally identified by van den Bergh(1981), that the surface brightnesses of galaxies in the higher redshiftclusters are in the mean found to be lower than in nearby clusters atfixed velocity width, is discussed. The extent to which this effect isaccounted for by galaxy diameter errors is investigated in detail.Cluster distance moduli and Hubble ratios are derived after firstconsidering a number of potential biases in the data. A variety of solarmotion solutions are obtained with respect to the reference frame of theclusters, and the value of the Hubble constant is discussed. The finalcluster Hubble ratios exhibit considerable scatter, signifying thepresence of an unaccounted for Local Group streaming motion. Formalsolution leads to a velocity in close agreement with the 3 K dipoleanisotropy.
|An analysis of the narrow line profiles in Seyfert 2 galaxies|
In the present analysis of the line profiles in 18 high ionizationSeyfert 2 galaxies, two-thirds of the sample exhibit a correlationbetween emission line width and critical density. The O III forbiddenline at 4363 A appears broader than that at 5007 A in 70 percent of thegalaxies, while the O I 6300 A forbidden line is broader than the S IIforbidden line at 6716 A in 66 percent of the cases; this stronglysuggests a model in which optically thick emission line clouds occupythe regions of highest density and velocity dispersion. The equivalentwidths of the Mg I 5176 A and Fe I 5270 A absorption features are usedto estimate the fraction of the featureless continuum at 5000 A, and acorrelation is found between the H-beta emission line equivalent widthand the line widths for all emission lines. No other significantcorrelations are found between emission line widths and other measuredparameters.
|A catalog of radio, optical, and infrared observations of spiral galaxies in clusters|
The results of a major observational program on the luminosities,colors, and gas contents of spiral galaxies in clusters of galaxies arepresented. The data have been used as part of a detailed investigationinto the nature of cluster spirals and for revisions of the distancescale using the infrared Tully-Fisher relation. The observationalstrategies, reduction procedures, and sources or error are brieflydiscussed. The data include 21-cm H I observations, UBVR multiaperturephotometry, and H-band photometry of several hunderd spiral galaxies in10 clusters.
|Photoionization models for Liners - Gas distribution and abundances|
Low-ionization nuclear emission regions (Liners) in galaxies arecharacterized on the basis of a statistical analysis of all availableobservational data and a review of theoretical models based onphotoionization by the nonthermal UV spectrum. The results are presentedin graphs and tables and characterized in detail. A good correlationwhich is unaffected by reddening or geometrical parameters and includesobjects with Balmer lines or X-ray flux is found by plotting the ratioof forbidden O III to (H-alpha)/3 against the forbidden (O I)/(O III)ratio. Models based on photoionization by a nonstellar object and havingpower-law index -2.0 and near-solar metallicity are computed; the O/Nabundance ratio is found to vary by a factor of three or less; thenuclear-gas abundances of O, N, and S are seen as approximately uniform;the characteristics of the brightest objects are attributed to opticallythin clouds or to nuclear H II regions; and Liners are shown to form asubgroup of normal galaxies with emission lines, with no physicallybased separation from other higher-excitation objects (except Seyfertgalaxies).
|The Cancer Cluster - an unbound collection of groups|
A surface density contour map of the Cancer Cluster derived from galaxycounts in the Zwicky catalog is presented. The contour map shows thatthe galaxy distribution is clumpy. When this spatial distribution iscombined with nearly complete velocity information, the clumps stand outmore clearly; there are significant differences in the mean velocitiesof the clumps which exceed their internal velocity dispersions. TheCancer Cluster is not a proper 'cluster' but is a collection of discretegroups, each with a velocity dispersion of approximately 300 km/s,separating from one another with the cosmological flow. Themass-to-light ratio for galaxies in the main concentration isapproximately 320 solar masses/solar luminosities (H0 = 100km/s Mpc).
|Are there any shock-heated galaxies|
Attention is given to the spectra of low-ionization nuclearemission-line regions (Liners) of galaxies as compared to other activegalactic nuclei. Results are presented for extensive photoionizationmodel calculations which are employed for the investigation of lineratio diagrams. The diagrams show that broad-line objects, Seyfert 2galaxies and Liners form a continuous smooth sequence of decreasingionization parameter. The data suggest a common source for lineexcitation in all of them. The results indicate that: (1)photoionization by a nonthermal source can explain the observed spectraof all active nuclei; (2) several weak lines differentiate betweenphotoionization and shock-heated models; and (3) the nonthermal ionizingcontinuum observed in several Liners is consistent with observed linefluxes.
|Empirical results from a study of active galactic nuclei|
Spectrophotometric observations are presented for emission-linegalaxies. When combined with previous Lick Observatory measurements,they are used to deduce criteria that allow the Seyfert 2 phenomena tobe quantitatively isolated from the narrow-emission-line galaxies. Thesecriteria are based on the finding that galaxies with forbidden line OIII 5007 A/H-beta ratios lower than 3 have emission line widths that areusually considerably smaller than the widths in galaxies with forbiddenline O III 5007 A/H-beta ratios greater than 3. In addition, large He II4686 A/H-beta ratios are consistent with forbidden line O III 5007A/H-beta ratios greater than 3. The physical conditions in thenarrow-line regions of Seyfert 1 galaxies are compared with those inSeyfert 2 galaxies. Significant differences are found for thetemperature-sensitive forbidden line O III ratio, and for the luminosityof Fe VII forbidden line 6087 A relative to the luminosity of thelow-ionization forbidden lines.
|Emission-line-continuum correlations in active galactic nuclei|
Continuum properties of emission-line galaxies and Seyfert 2 galaxiesare presented. When these results are compared with previously publisheddata, H-alpha is found to correlate over a range of 7 orders ofmagnitude with the optical featureless continuum. This implies that theparameters affecting H-alpha might be uniform from emission-linegalaxies to QSOs. Other emission-line luminosities are found tocorrelate well with the continuum luminosity. Both the H-alpha and He II4686 A relations are consistent with a photoionization hypothesis, butonly if the ionizing continuum has a high-frequency turnoff betweenapproximately 60 and 175 eV.
|Accurate Optical Positions of Arakelian Galaxies|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1981AJ.....86..820K&db_key=AST
|Galaxies of high surface brightness|
Two lists are presented which contain 621 galaxies whose surfacebrightness, as derived from their apparent magnitudes, is at least 22.0magnitudes from an area of 1 sq arcsec. The lists were compiled in anattempt to verify observationally a possible correlation between surfacebrightness and nuclear activity. Four percent of all the galaxies in anarea of 4.5 sr at declinations higher than -3 deg and galactic latitudesgreater than 20 deg are listed, including 30 Markarian, 29 Zwicky, and 7blue Haro galaxies. A morphological study of 130 of the galaxiesindicates that about half are elliptical or lenticular, 50 are compactor peculiar, and that there is an excess of elliptical and lenticularobjects in comparison with a random sample. Notes on the morphologicaltypes and colors of the galaxies are provided along with identificationcharts.
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