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Публикации по объекту
Objective Classification of Spiral Galaxies Having Extended Rotation Curves Beyond the Optical Radius
We carry out an objective classification of four samples of spiralgalaxies having extended rotation curves beyond the optical radius. Amultivariate statistical analysis (viz., principal component analysis[PCA]) shows that about 96% of the total variation is due to twocomponents, one being the combination of absolute blue magnitude andmaximum rotational velocity beyond the optical region and the otherbeing the central density of the halo. On the basis of PCA a fundamentalplane has been constructed that reduces the scatter in the Tully-Fisherrelation up to a maximum of 16%. A multiple stepwise regression analysisof the variation of the overall shape of the rotation curves shows thatit is mainly determined by the central surface brightness, while theshape purely in the outer part of the galaxy (beyond the optical radius)is mainly determined by the size of the galactic disk.
| The Baryonic Tully-Fisher Relation of Galaxies with Extended Rotation Curves and the Stellar Mass of Rotating Galaxies
I investigate the baryonic Tully-Fisher relation for a sample ofgalaxies with extended 21 cm rotation curves spanning the range 20 kms-1<~Vf<=300 km s-1. A variety ofscalings of the stellar mass-to-light ratio Υ* areconsidered. For each prescription for Υ*, I give fitsof the form Md=AVxf.Presumably, the prescription that comes closest to the correct valuewill minimize the scatter in the relation. The fit with minimum scatterhas A=50 Msolar km-4 s4 andx=4. This relation holds over five decades in mass. Galaxy color,stellar fraction, and Υ* are correlated with eachother and with Md, in the sense that more massivegalaxies tend to be more evolved. There is a systematic dependence ofthe degree of maximality of disks on surface brightness. High surfacebrightness galaxies typically have Υ*~3/4 of themaximum disk value, while low surface brightness galaxies typicallyattain ~1/4 of this amount.
| Rotational Widths for Use in the Tully-Fisher Relation. I. Long-Slit Spectroscopic Data
We present new long-slit Hα spectroscopy for 403 noninteractingspiral galaxies, obtained at the Palomar Observatory 5 m Hale telescope,which is used to derive well-sampled optical rotation curves. Becausemany of the galaxies show optical emission features that aresignificantly extended along the spectrograph slit, a technique wasdevised to separate and subtract the night sky lines from the galaxyemission. We exploit a functional fit to the rotation curve to identifyits center of symmetry; this method minimizes the asymmetry in thefinal, folded rotation curve. We derive rotational widths using bothvelocity histograms and the Polyex model fit. The final rotational widthis measured at a radius containing 83% of the total light as derivedfrom I-band images. In addition to presenting the new data, we use alarge sample of 742 galaxies for which both optical long-slit and radioH I line spectroscopy are available to investigate the relation betweenthe H I content of the disks and the extent of their rotation curves.Our results show that the correlation between those quantities, which iswell established in the case of H I-poor galaxies in clusters, ispresent also in H I-normal objects: for a given optical size, starformation can be traced farther out in the disks of galaxies with largerH I mass.
| HI-observations of blue compact dwarf galaxies
We present HI-observations of 56 blue compact dwarf (BCD) galaxies ofwhich 44 have been detected in the 21-cm line from neutral hydrogen withthe 100-m radiotelescope at Effelsberg. Optical data (e.g., from NED)and HI data from other observers and telescopes are used to estimate thelikelihood of confusion from other galaxies within the Effelsberg beam.The selected 29 BCD galaxies without any sign of confusion are used toinfer several characteristic properties of the BCD galaxy population. Insome respects, they resemble normal galaxies: e.g., the relationsbetween global parameters like linear diameter A0 versus blueluminosity LB and the MHI/LB ratio vs.LB. At least five of these BCDGs emit milli-Jansky levelradio continuum emission.
| The Hα galaxy survey. I. The galaxy sample, Hα narrow-band observations and star formation parameters for 334 galaxies
We discuss the selection and observations of a large sample of nearbygalaxies, which we are using to quantify the star formation activity inthe local Universe. The sample consists of 334 galaxies across allHubble types from S0/a to Im and with recession velocities of between 0and 3000 km s-1. The basic data for each galaxy are narrowband H\alpha +[NII] and R-band imaging, from which we derive starformation rates, H\alpha +[NII] equivalent widths and surfacebrightnesses, and R-band total magnitudes. A strong correlation is foundbetween total star formation rate and Hubble type, with the strongeststar formation in isolated galaxies occurring in Sc and Sbc types. Moresurprisingly, no significant trend is found between H\alpha +[NII]equivalent width and galaxy R-band luminosity. More detailed analyses ofthe data set presented here will be described in subsequent papers.Based on observations made with the Jacobus Kapteyn Telescope operatedon the island of La Palma by the Isaac Newton Group in the SpanishObservatorio del Roque de los Muchachos of the Instituto deAstrofísica de Canarias.The full version of Table \ref{tab3} is available in electronic form atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/414/23 Reduced image datafor this survey can be downloaded fromhttp://www.astro.livjm.ac.uk/HaGS/
| Companions of Bright Barred Shapley-Ames Galaxies
Companion galaxy environment for a subset of 78 bright and nearby barredgalaxies from the Shapley-Ames Catalog is presented. Among the spiralbarred galaxies, there are Seyfert galaxies, galaxies with circumnuclearstructures, galaxies not associated with any large-scale galaxy cloudstructure, galaxies with peculiar disk morphology (crooked arms), andgalaxies with normal disk morphology; the list includes all Hubbletypes. The companion galaxy list includes the number of companiongalaxies within 20 diameters, their Hubble type, and projectedseparation distance. In addition, the companion environment was searchedfor four known active spiral galaxies, three of them are Seyfertgalaxies, namely, NGC 1068, NGC 1097, and NGC 5548, and one is astarburst galaxy, M82. Among the results obtained, it is noted that theonly spiral barred galaxy classified as Seyfert 1 in our list has nocompanions within a projected distance of 20 diameters; six out of 10Seyfert 2 bar galaxies have no companions within 10 diameters, six outof 10 Seyfert 2 galaxies have one or more companions at projectedseparation distances between 10 and 20 diameters; six out of 12 galaxieswith circumnuclear structures have two or more companions within 20diameters.
| The luminous and dark matter content of disk galaxies
We have compiled a sample of disk galaxies with available photometry inthe B and K bands, velocity line-widths and HI integral fluxes. Severalparameters that trace the luminous, baryonic and dark matter contentswere inferred. We investigated how these parameters vary with differentgalaxy properties, and compared the results with predictions of galaxyevolutionary models in the context of the Λ Cold Dark Matter(ΛCDM) cosmogony. The ratio of disk-to-total maximum circularvelocity, (Vd,m/Vt,m), depends mainly on thecentral disk surface density Σd,0 (or surfacebrightness, SB), increasing roughly asΣd,00.15. While a fraction of high SBgalaxies have a (Vd,m/Vt,m) ratio corresponding tothe maximum disk solution, the low SB are completely dark matterdominated. The trend is similar for the models, although they haveslightly smaller (Vd,m/Vt,m) ratios thanobservations, in particular at the highest SBs and when small baryonfractions are used. The scatter in the(Vd,m/Vt,m)- Σd,0 plot is large.An analysis of residuals shows that (Vd,m/Vt,m)tends to decrease as the galaxy is redder, more luminous (massive), andof earlier type. The models allow us to explain the physics of theseresults, which imply a connexion between halo structure and luminousproperties. The dynamical-to-baryon mass and dynamical mass-to-light (Band K) ratios at a given radius were also estimated. All these ratios,for observations and models, decrease with Σd,0; (orSB) and do not correlate significantly with the galaxy scale, contraryto what has been reported in previous works, based on the analysis ofrotation curve shapes. We discuss this difference and state theimportance of solving the controversy of whether the dark and luminouscontents in disk galaxies depend on SB or luminosity. The broadagreement between the models and observations presented here regardingthe trends of the dynamical-to-baryon matter and mass-to-light ratioswith several galaxy properties favors the ΛCDM scenario. However,the excess of dark matter inside the optical region of disk galaxiesremains the main difficulty.Appendices A and B are only available in electronic form athttp://www.edpsciences.org. Table 1 is only available at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/412/633
| Modified Newtonian Dynamics as an Alternative to Dark Matter
Modified Newtonian dynamics (MOND) is an empirically motivatedmodification of Newtonian gravity or inertia suggested by Milgrom as analternative to cosmic dark matter. The basic idea is that ataccelerations below ao ~ 10-8 cm/s2 ~cHo/6 the effective gravitational attraction approaches√(gnao), where gn is the usualNewtonian acceleration. This simple algorithm yields flat rotationcurves for spiral galaxies and a mass-rotation velocity relation of theform M ∝ V4 that forms the basis for the observedluminosity-rotation velocity relation-the Tully-Fisher law. We reviewthe phenomenological success of MOND on scales ranging from dwarfspheroidal galaxies to superclusters and demonstrate that the evidencefor dark matter can be equally well interpreted as evidence for MOND. Wediscuss the possible physical basis for an acceleration-basedmodification of Newtonian dynamics as well as the extention of MOND tocosmology and structure formation.
| The Radio Properties of Composite LINER/H II Galaxies
Arcsecond-resolution VLA observations-newly obtained as well aspublished-of 40 nearby galaxies are discussed, completing a study of theradio properties of a magnitude-limited sample of nearby galaxies of thecomposite LINER/H II type. Our results reveal an overall detection rateof at least 25% active galactic nucleus (AGN) candidates among thesecomposite sources. The general properties of these AGN candidates, ascompared to non-AGN composite sources and H II galaxies, are discussed.
| The H I Line Width/Linear Diameter Relationship as an Independent Test of the Hubble Constant
The relationship between corrected H I line widths and linear diameters(LW/LD) for spiral galaxies is used as an independent check on the valueof the Hubble constant. After calibrating the Tully-Fisher (TF) relationin both the B and I bands, the B-band relation is used for galaxies ofmorphological/luminosity types Sc I, Sc I.2, Sc I.3, Sab, Sb, Sb I-II,and Sb II to derive the LW/LD relation. We find that for this sample thescatter in the LW/LD is smallest with a Hubble constant of 90-95 kms-1 Mpc-1. Lower values of the Hubble constantproduce a separation in the LW/LD relation that is a function ofmorphological type. Since a Hubble constant of 90-95 is significantlylarger than the final Key Project value of 72 km s-1Mpc-1, a comparison of TF, surface brightness fluctuation(SBF), and fundamental plane (FP) is made. This comparison indicatesthat the Key Project TF distances to 21 clusters may be too large. For asample of 11 clusters, the Key Project TF distances provide anunweighted mean Hubble constant of 77 km s-1Mpc-1, while a combination of the FP, SBF, and our TFdistances for the same 11 clusters gives H0=91 kms-1 Mpc-1. A more subtle result in our data is amorphological dichotomy in the Hubble constant. The data suggest that ScI galaxies follow a Hubble constant of 90-95 while Sb galaxies follow aHubble constant closer to 75 km s-1 Mpc-1.Possible explanations for this result are considered, but it is shownthat this Sb/Sc I Hubble flow discrepancy is also present in the VirgoCluster and is consistent with previous investigations that indicatethat some galaxies carry a component of age-related intrinsic redshift.
| Bar Galaxies and Their Environments
The prints of the Palomar Sky Survey, luminosity classifications, andradial velocities were used to assign all northern Shapley-Ames galaxiesto either (1) field, (2) group, or (3) cluster environments. Thisinformation for 930 galaxies shows no evidence for a dependence of barfrequency on galaxy environment. This suggests that the formation of abar in a disk galaxy is mainly determined by the properties of theparent galaxy, rather than by the characteristics of its environment.
| The dark matter distribution in disc galaxies
We use high-quality optical rotation curves of nine low-luminosity discgalaxies to obtain the velocity profiles of the surrounding dark matterhaloes. We find that they increase linearly with radius at least out tothe edge of the stellar disc, implying that, over the entire stellarregion, the density of the dark halo is about constant. The propertiesof the mass structure of these haloes are similar to those found for anumber of dwarf and low surface brightness galaxies, but provide a moresubstantial evidence of the discrepancy between the halo massdistribution predicted in the cold dark matter scenario and thoseactually detected around galaxies. We find that the density law proposedby Burkert reproduces the halo rotation curves, with halo centraldensities (ρ0~1-4×10-24gcm-3)and core radii (r0~5-15kpc) scaling asρ0~r0-2/3.
| The Ursa Major Cluster of Galaxies. V. H I Rotation Curve Shapes and the Tully-Fisher Relations
This paper investigates the statistical properties of the Tully-Fisher(TF) relations for a volume-limited complete sample of spiral galaxiesin the nearby Ursa Major Cluster. The merits of B, R, I, and K' surfacephotometry and the availability of detailed kinematic information from HI synthesis imaging have been exploited. In addition to the corrected HI global profile widths WiR,I, the available H Irotation curves allow direct measurements of the observed maximumrotational velocities Vmax and the amplitudesVflat of the outer flat parts. The dynamical state of the gasdisks could also be determined in detail from the radio observations.The four luminosity and three kinematic measures allowed theconstruction of 12 correlations for various subsamples. For large galaxysamples, the Mb,iR-logWiR,Icorrelation in conjunction with strict selection criteria is preferredfor distance determinations with a 7% accuracy. Galaxies with rotationcurves that are still rising at the last measured point liesystematically on the low-velocity side of the TF relation. Galaxieswith a partly declining rotation curve(Vmax>Vflat) tend to lie systematically on thehigh-velocity side of the relation when usingWiR,I or Vmax. However, systematicoffsets are eliminated when Vflat is used. Residuals of theMb,iB-log(2Vflat) relation correlateconsistently with global galaxy properties along the Hubble sequencelike morphological type, color, surface brightness, and gas massfraction. These correlations are absent for the near-infraredMb,iK'-log(2Vflat)residuals. The tightest correlation(χ2red=1.1) is found for theMb,iK'-log(2Vflat) relation,which has a slope of -11.3+/-0.5 and a total observed scatter of 0.26mag with a most likely intrinsic scatter of zero. The tightness of thenear-infrared correlation is preserved when converting it into abaryonic TF relation that has a slope of -10.0 in the case(Mgas/LK')=1.6 while a zerointrinsic scatter remains most likely. Based on the tightness of thenear-infrared and baryonic correlations, it is concluded that the TFrelation reflects a fundamental correlation between the mass of the darkmatter halo, measured through its induced maximum rotational velocityVflat, and the total baryonic mass Mbar of agalaxy where Mbar~V4flat. Althoughthe actual distribution of the baryonic matter inside halos of similarmass can vary significantly, it does not affect this relation.
| The Frequency of Active and Quiescent Galaxies with Companions: Implications for the Feeding of the Nucleus
We analyze the idea that nuclear activity, either active galactic nuclei(AGNs) or star formation, can be triggered by interactions by studyingthe percentage of active, H II, and quiescent galaxies with companions.Our sample was selected from the Palomar survey and avoids selectionbiases faced by previous studies. This sample was split into fivedifferent groups, Seyfert galaxies, LINERs, transition galaxies, H IIgalaxies, and absorption-line galaxies. The comparison between the localgalaxy density distributions of the different groups showed that in mostcases there is no statistically significant difference among galaxies ofdifferent activity types, with the exception that absorption-linegalaxies are seen in higher density environments, since most of them arein the Virgo Cluster. The comparison of the percentage of galaxies withnearby companions showed that there is a higher percentage of LINERs,transition galaxies, and absorption-line galaxies with companions thanSeyfert and H II galaxies. However, we find that when we consider onlygalaxies of similar morphological types (elliptical or spiral), there isno difference in the percentage of galaxies with companions amongdifferent activity types, indicating that the former result was due tothe morphology-density effect. In addition, only small differences arefound when we consider galaxies with similar Hα luminosities. Thecomparison between H II galaxies of different Hα luminositiesshows that there is a significantly higher percentage of galaxies withcompanions among H II galaxies with L(Hα)>1039 ergss-1 than among those with L(Hα)<=1039ergs s-1, indicating that interactions increase the amount ofcircumnuclear star formation, in agreement with previous results. Thefact that we find that galaxies of different activity types have thesame percentage of companions suggests that interactions betweengalaxies is not a necessary condition to trigger the nuclear activity inAGNs. We compare our results with previous ones and discuss theirimplications.
| Environment status of blue compact galaxies and trigger of star formation
The work studies of the environment of low-mass galaxies with activestar formation (SF) and a possible trigger of SF bursts due togravitational interaction. Following the study by Taylor et al. (1995),we extend the search for possible disturbing galaxies of various massesto a much larger sample of 86 BCGs from the sky region of the SecondByurakan survey (SBS). The BCG magnitudes and radial velocities arerevised and up-dated. The sample under study is separated by thecriteria: EW([O III]λ5007) > 45 Å andVh < 6,000 kms and should be representative of alllow-mass galaxies which experience SF bursts. We argue that the moderatetidal disturbers should be taken into account, and incorporate therespective range of distances in the search for disturbing neighbours.The majority of the neighbours in the vicinity of the studied BCGs arefound through the study of their environment among UZC (Falco et al.\cite{Falco99}) galaxies, and the follow-up careful search of thefainter galaxies in the NED database. For the remaining BCGs, theneighbouring galaxies are found based on the results of the SAO 6mtelescope spectroscopy. By studing the data on the radial velocities ofgalaxies in the vicinity of BCGs we found: 1) 33 of the studied BCGs(~38.5%) are associated with significantly brighter galaxies (Δ B>= 1.5m); 2) 23 BCGs (~26.5%) have neighbours either ofcomparable or significantly lower brightness; 3) 14 of the studied BCGs(16\%) with no evident associated galaxy are either certain, orprobable, mergers. Summarizing, we conclude that in ~80% (or more) BCGsfrom the studied sample, the SF bursts are triggered either by tidalaction of various strengths from other galaxies, or due to mergers oflow-mass galaxies. We briefly discuss the implications of our mainconclusion for evolutionary links of BCGs to other types of low-massgalaxies. Part of our sample falls into the volume belonging to theLocal Supercluster. Therefore we formulate the results separately on the``Local Supercluster volume'' and ``general field region''. The totalfractions of BCGs likely triggered by interaction with other galaxy arerespectively, ~84.5% and 80% for the nearby volume and for the generalfield. The fractions of BCGs with significantly brighter disturbers inthese two groups are seemingly different (~54±14% vs.~31.5±7%, respectively). Among the so called ``isolated'' BCGs(that is, without a bright neighbouring galaxy) in both the LocalSupercluster volume and in general field, ~43±10% are probablydisturbed by dwarf galaxies and ~26±8% have a merger morphology.In the Appendix we present the results of the spectroscopy with the SAO6m telescope of 27 galaxies in an attempt to find possible disturbinggalaxies in the vicinity of some of the sample BCGs. Tables 2, 3 and A.1with their notes and Figs. A.1-A.3 are only available in electronic format http://www.edpsciences.org
| The Ursa Major cluster of galaxies. IV. HI synthesis observations
In this data paper we present the results of an extensive 21 cm-linesynthesis imaging survey of 43 spiral galaxies in the nearby Ursa Majorcluster using the Westerbork Synthesis Radio Telescope. Detailedkinematic information in the form of position-velocity diagrams androtation curves is presented in an atlas together with HI channel maps,21 cm continuum maps, global HI profiles, radial HI surface densityprofiles, integrated HI column density maps, and HI velocity fields. Therelation between the corrected global HI linewidth and the rotationalvelocities Vmax and Vflat as derived from therotation curves is investigated. Inclination angles obtained from theoptical axis ratios are compared to those derived from the inclined HIdisks and the HI velocity fields. The galaxies were not selected on thebasis of their HI content but solely on the basis of their clustermembership and inclination which should be suitable for a kinematicanalysis. The observed galaxies provide a well-defined, volume limitedand equidistant sample, useful to investigate in detail the statisticalproperties of the Tully-Fisher relation and the dark matter halos aroundthem.
| 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.
| Radio Sources in Low-Luminosity Active Galactic Nuclei. I. VLA Detections of Compact, Flat-Spectrum Cores
We report a high-resolution (0.2"), 15 GHz survey of a sample of 48low-luminosity active galactic nuclei with the Very LargeArray.5 Compact radio emission has beendetected above a flux density of 1.1 mJy in 57% (17 of 30) oflow-ionization nuclear emission-line region (LINER) nuclei andlow-luminosity Seyfert galaxies. The 2 cm radio power is significantlycorrelated with the emission-line ([O I] λ6300) luminosity. Usingradio fluxes at other frequencies from the literature, we find that atleast 15 of the 18 detected radio cores have a flat to inverted spectrum(α>=-0.3, Sν~να). While thepresent observations are consistent with the radio emission originatingin star-forming regions (the brightness temperatures are>=102.5-4.5 K), higher resolution radio observations of 10of the detected sources, reported in an accompanying paper, show thatthe cores are very compact (<~1 pc), of high brightness temperature(Tb>~108 K), and probably synchrotronself-absorbed, ruling out a starburst origin. Thus, our results suggestthat at least 50% of low-luminosity Seyfert galaxies and LINERs in thesample are accretion powered, with the radio emission presumably comingfrom jets or advection-dominated accretion flows. We have detected only1 of 18 ``transition'' (i.e., LINER+H II) nuclei observed, indicatingthat their radio cores are significantly weaker than those of ``pure''LINERs. Compact 2 cm radio cores are found in both type 1 (i.e., withbroad Hα) and type 2 (without broad Hα) nuclei. There isweak evidence, limited in significance by small numbers, thatlow-luminosity active galactic nuclei with compact radio cores exhibitradio ejecta preferentially aligned along the rotation axis of thegalaxy disk. If this result were confirmed by a larger sample, it wouldlend support to the idea that the misalignment of accretion disks withthe galaxy stellar disk in more luminous Seyfert galaxies is a result ofradiation-pressure-induced warping of their accretion disks.
| Is a Simple Collisionless Relic Dark Matter Particle Ruled Out?
The central densities of dark matter (DM) halos are much lower thanpredicted in cold DM models of structure formation. Confirmation thatthey have cores with a finite central density would allow us to rule outmany popular types of collisionless particles as candidates for DM. Anymodel that leads to cusped halos (such as cold DM) is already facingserious difficulties on small scales, and hot DM models have beenexcluded. Here I show that fermionic warm DM is inconsistent with thewide range of phase-space densities in the DM halos of well-observednearby galaxies.
| The Correlation between Galaxy H I Line Widths and K'Luminosities
The relationship between galaxy luminosities and rotation rates isstudied with total luminosities in the K' band. Extinction problems areessentially eliminated at this band centered at 2.1 μm. A templateluminosity-line width relation is derived based on 65 galaxies drawnfrom two magnitude-limited cluster samples. The zero point is determinedusing four galaxies with accurately known distances. The calibration isapplied to give the distance to the Pisces Cluster (59 Mpc) at aredshift in the cosmic microwave background frame of 4771 kms-1. The resultant value of the Hubble constant is 81 kms-1Mpc-1. The largest sources of uncertainty arethe small number of zero-point calibrators at this time at K' and thepresent application to only one cluster.
| Distances to Galaxies from the Correlation between Luminosities and Line Widths. III. Cluster Template and Global Measurement of H0
The correlation between the luminosities and rotation velocities ofgalaxies can be used to estimate distances to late-type galaxies. It isan appropriate moment to reevaluate this method given the great deal ofnew information available. The major improvements described hereinclude: (1) the template relations can now be defined by large,complete samples, (2) the samples are drawn from a wide range ofenvironments, (3) the relations are defined by photometric informationat the B, R, I, and K' bands, (4) the multiband information clarifiesproblems associated with internal reddening, (5) the template zeropoints are defined by 24 galaxies with accurately known distances, and(6) the relations are applied to 12 clusters scattered across the skyand out to velocities of 8000 km s-1. The biggest change fromearlier calibrations are associated with point 5. Roughly a 15% increasein the distance scale has come about with the fivefold increase in thenumber of zero-point calibrators. The overall increase in the distancescale from the luminosity-line width methodology is about 10% afterconsideration of all factors. Modulo an assumed distance to the LargeMagellanic Cloud of 50 kpc and no metallicity corrections to the Cepheidcalibration, the resulting value of the Hubble constant isH0=77+/-8 km s-1 Mpc-1, where the erroris the 95% probable statistical error. Cumulative systematic errorsinternal to this analysis should not exceed 10%. Uncertainties in thedistance scale ladder external to this analysis are estimated at ~10%.If the Cepheid calibration is shifted from the LMC to NGC 4258 with adistance established by observations of circumnuclear masers, thenH0 is larger by 12%.
| Box- and peanut-shaped bulges. I. Statistics
We present a classification for bulges of a complete sample of ~ 1350edge-on disk galaxies derived from the RC3 (Third Reference Catalogue ofBright Galaxies, de Vaucouleurs et al. \cite{rc3}). A visualclassification of the bulges using the Digitized Sky Survey (DSS) inthree types of b/p bulges or as an elliptical type is presented andsupported by CCD images. NIR observations reveal that dust extinctiondoes almost not influence the shape of bulges. There is no substantialdifference between the shape of bulges in the optical and in the NIR.Our analysis reveals that 45% of all bulges are box- and peanut-shaped(b/p). The frequency of b/p bulges for all morphological types from S0to Sd is > 40%. In particular, this is for the first time that such alarge frequency of b/p bulges is reported for galaxies as late as Sd.The fraction of the observed b/p bulges is large enough to explain theb/p bulges by bars. Partly based on observations collected at ESO/LaSilla (Chile), DSAZ/Calar Alto (Spain), and Lowell Observatory/Flagstaff(AZ/U.S.A.). Tables 6 and 7 are only available in electronic form at CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| 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.
| Rotation Curves of Ursa Major Galaxies in the Context of Modified Newtonian Dynamics
This is the third in a series of papers in which spiral galaxy rotationcurves are considered in the context of Milgrom's modified dynamics(MOND). The present sample of 30 objects is drawn from a complete sampleof galaxies in the Ursa Major cluster, with photometric data from Tullyet al. and 21 cm line data from Verheijen. The galaxies are roughly allat the same distance (15 to 16 Mpc). The radio observations are madewith the Westerbork Synthesis Array, which means that the linearresolution of all rotation curves is comparable. The greatest advantageof this sample is the existence of K'-band surface photometry for allgalaxies; the near-infrared emission, being relatively free of theeffects of dust absorption and less sensitive to recent star formation,is a more precise tracer of the mean radial distribution of the dominantstellar population. The predicted rotation curves are calculated fromthe K'-band surface photometry and the observed distribution of neutralhydrogen using the simple MOND prescription, in which the one adjustableparameter is the mass of the stellar disk or the implied mass-to-lightratio. The predicted rotation curves generally agree with the observedcurves, and the mean M/L in the near-infrared is about 0.9 with a smalldispersion. The fitted M/L in the B-band correlates with B-V color inthe sense predicted by population synthesis models. Including earlierwork, about 80 galaxy rotation curves are now well reproduced from theobserved distribution of detectable matter using the MOND formula tocalculate the gravitational acceleration; this lends considerableobservational support to Milgrom's unconventional hypothesis.
| Groups of galaxies. III. Some empirical characteristics.
Not Available
| Bulge-Disk Decomposition of 659 Spiral and Lenticular Galaxy Brightness Profiles
We present one of the largest homogeneous sets of spiral and lenticulargalaxy brightness profile decompositions completed to date. The 659galaxies in our sample have been fitted with a de Vaucouleurs law forthe bulge component and an inner-truncated exponential for the diskcomponent. Of the 659 galaxies in the sample, 620 were successfullyfitted with the chosen fitting functions. The fits are generally welldefined, with more than 90% having rms deviations from the observedprofile of less than 0.35 mag. We find no correlations of fittingquality, as measured by these rms residuals, with either morphologicaltype or inclination. Similarly, the estimated errors of the fittedcoefficients show no significant trends with type or inclination. Thesedecompositions form a useful basis for the study of the lightdistributions of spiral and lenticular galaxies. The object base issufficiently large that well-defined samples of galaxies can be selectedfrom it.
| Catalogue of HI maps of galaxies. I.
A catalogue is presented of galaxies having large-scale observations inthe HI line. This catalogue collects from the literature the informationthat characterizes the observations in the 21-cm line and the way thatthese data were presented by means of maps, graphics and tables, forshowing the distribution and kinematics of the gas. It containsfurthermore a measure of the HI extension that is detected at the levelof the maximum sensitivity reached in the observations. This catalogueis intended as a guide for references on the HI maps published in theliterature from 1953 to 1995 and is the basis for the analysis of thedata presented in Paper II. The catalogue is only available inelectronic form at the CDS via anonymous ftp 130.79.128.5 orhttp://cdsweb.u-strasbg.fr/Abstract.html
| 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
| A Search for ``Dwarf'' Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies
We have completed an optical spectroscopic survey of the nuclear regions(r <~ 200 pc) of a large sample of nearby galaxies. Although the mainobjectives of the survey are to search for low-luminosity activegalactic nuclei and to quantify their luminosity function, the databasecan be used for a variety of other purposes. This paper presentsmeasurements of the spectroscopic parameters for the 418 emission-linenuclei, along with a compilation of the global properties of all 486galaxies in the survey. Stellar absorption generally poses a seriousobstacle to obtaining accurate measurement of emission lines in nearbygalactic nuclei. We describe a procedure for removing the starlight fromthe observed spectra in an efficient and objective manner. The mainparameters of the emission lines (intensity ratios, fluxes, profilewidths, and equivalent widths) are measured and tabulated, as areseveral stellar absorption-line and continuum indices useful forstudying the stellar population. Using standard nebular diagnostics, wedetermine the probable ionization mechanisms of the emission-lineobjects. The resulting spectral classifications provide extensiveinformation on the demographics of emission-line nuclei in the nearbyregions of the universe. This new catalog contains over 200 objectsshowing spectroscopic evidence for recent star formation and an equallylarge number of active galactic nuclei, including 46 that show broad Halpha emission. These samples will serve as the basis of future studiesof nuclear activity in nearby galaxies.
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