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Completing H I observations of galaxies in the Virgo cluster
High sensitivity (rms noise 0.5 mJy) 21-cm H I line observationswere made of 33 galaxies in the Virgo cluster, using the refurbishedArecibo telescope, which resulted in the detection of 12 objects. Thesedata, combined with the measurements available from the literature,provide the first set of H I data that is complete for all 355 late-type(Sa-Im-BCD) galaxies in the Virgo cluster with mp ≤ 18.0mag. The Virgo cluster H I mass function (HIMF) that was derived forthis optically selected galaxy sample is in agreement with the HIMFderived for the Virgo cluster from the blind HIJASS H I survey and isinconsistent with the Field HIMF. This indicates that both in this richcluster and in the general field, neutral hydrogen is primarilyassociated with late-type galaxies, with marginal contributions fromearly-type galaxies and isolated H I clouds. The inconsistency betweenthe cluster and the field HIMF derives primarily from the difference inthe optical luminosity function of late-type galaxies in the twoenvironments, combined with the HI deficiency that is known to occur ingalaxies in rich clusters.Tables \ref{t1, \ref{sample_dat} and Appendix A are only available inelectronic form at http://www.edpsciences.org
| Spectrophotometry of galaxies in the Virgo cluster. II. The data
Drift-scan mode (3600-6800 Å) spectra with 500
| New optical velocities of nearby dwarf LSB galaxies
We present radial velocities for nearby dwarf galaxy candidates found byKarachentseva & Karachentsev (\cite{Karachentseva1998}) on thePOSS-II films. Out of 118 observed objects, 88 have been detected in theHalpha line. Their median radial velocity is 1750 kms-1. A quarter of the galaxies belong to the Local Volume,having corrected radial velocities V_LG < 500 km s-1. Someof them are members of the nearby groups around Maffei/IC 342, M 81, andNGC 6946.
| UV to radio centimetric spectral energy distributions of optically-selected late-type galaxies in the Virgo cluster
We present a multifrequency dataset for an optically-selected,volume-limited, complete sample of 118 late-type galaxies (>=S0a) inthe Virgo cluster. The database includes UV, visible, near-IR, mid-IR,far-IR, radio continuum photometric data as well as spectroscopic dataof Hα , CO and HI lines, homogeneously reduced, obtained from ourown observations or compiled from the literature. Assuming the energybalance between the absorbed stellar light and that radiated in the IRby dust, we calibarte an empirical attenuation law suitable forcorrecting photometric and spectroscopic data of normal galaxies. Thedata, corrected for internal extinction, are used to construct thespectral energy distribution (SED) of each individual galaxy, andcombined to trace the median SED of galaxies in various classes ofmorphological type and luminosity. Low-luminosity, dwarf galaxies haveon average bluer stellar continua and higher far-IR luminosities perunit galaxy mass than giant, early-type spirals. If compared to nearbystarburst galaxies such as M 82 and Arp 220, normal spirals haverelatively similar observed stellar spectra but 10-100 times lower IRluminosities. The temperature of the cold dust component increases withthe far-IR luminosity, from giant spirals to dwarf irregulars. The SEDare used to separate the stellar emission from the dust emission in themid-IR regime. We show that the contribution of the stellar emission at6.75 mu m to the total emission of galaxies is generally important, from~ 80% in Sa to ~ 20% in Sc.Tables 2-5, 7, 8, and Fig. 2 are only available in electronic form athttp://www.edpsciences.orgTables 10-12 are only available in electronic form 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/402/37
| 1.65-μm (H -band) surface photometry of galaxies - VIII. The near-IR κ space at z =0
We present the distribution of a statistical sample of nearby galaxiesin the κ -space (κ 1 ~logM , κ 2~logI e 3 M /L , κ 3 ~logM /L ).Our study is based on near-IR (H -band: λ =1.65μm)observations, for the first time comprising early- and late-typesystems. Our data confirm that the mean effective dynamicalmass-to-light ratio M /L of the E+S0+S0a galaxies increases withincreasing effective dynamical mass M , as expected from the existenceof the Fundamental Plane relation. Conversely, spiral and Im/BCDgalaxies show a broad distribution in M /L with no detected trend of M/L with M , the former galaxies having M /L values about twice largerthan the latter, on average. For all the late-type galaxies, the M /Lincreases with decreasing effective surface intensity I e ,consistent with the existence of the Tully-Fisher relation. Theseresults are discussed on the basis of the assumptions behind theconstruction of the κ -space and their limitations. Our study iscomplementary to a previous investigation in the optical (B -band:λ =0.44μm) and allows us to study wavelength dependences ofthe galaxy distribution in the κ -space. As a first result, wefind that the galaxy distribution in the κ 1 -κ2 plane reproduces the transition from bulgeless tobulge-dominated systems in galaxies of increasing dynamical mass.Conversely, it appears that the M /L of late-types is higher (lower)than that of early-types with the same M in the near-IR (optical). Theorigins of this behaviour are discussed in terms of dust attenuation andstar formation history.
| Far-Infrared Photometry of a Statistical Sample of Late-Type Virgo Cluster Galaxies
We present deep diffraction-limited far-infrared (FIR) strip maps of asample of 63 galaxies later than S0 and brighter thanBT=16.8, selected from the Virgo Cluster Catalogue ofBinggeli, Sandage, & Tammann. The ISOPHOT instrument on board theInfrared Space Observatory was used to achieve sensitivities typicallyan order of magnitude deeper than IRAS in the 60 and 100 μm bands andto reach the confusion limit at 170 μm. The averaged 3 σ upperlimits for integrated flux densities of point sources at 60, 100, and170 μm are 43, 33, and 58 mJy, respectively. A total of 63.5% aredetected at all three wavelengths. The highest detection rate (85.7%) isin the 170 μm band. In many cases the galaxies are resolved, allowingthe scale length of the infrared disks to be derived from theoversampled brightness profiles in addition to the spatially integratedemission. The data presented should provide the basis for a variety ofstatistical investigations of the FIR spectral energy distributions ofgas-rich galaxies in the local universe spanning a broad range in starformation activity and morphological types, including dwarf systems andgalaxies with rather quiescent star formation activity. Based onobservations with the Infrared Space Observatory (ISO), an ESA projectwith instruments funded by ESA member states (especially the PIcountries: France, Germany, the Netherlands, and the United Kingdom) andwith the participation of ISAS and NASA.
| The Three-dimensional Structure of the Virgo Cluster Region from Tully-Fisher and H I Data
The distances and H I contents of 161 spiral galaxies in the region ofthe Virgo cluster are used to gain insight into the complicatedstructure of this galaxy system. Special attention has been paid to theinvestigation of the suggestion presented in an earlier work that someperipheral Virgo groups may contain strongly gas-deficient spiralgalaxies. The three-dimensional galaxy distribution has been inferredfrom quality distance estimates obtained by averaging distance modulibased on the Tully-Fisher relationship taken from eight published datasets previously homogenized, resulting in a relation with a dispersionof 0.41 mag. Previous findings that the spiral distribution issubstantially more elongated along the line of sight than in the planeof the sky are confirmed by the current data. In addition, an importanteast-west disparity in this effect has been detected. The overallwidth-to-depth ratio of the Virgo cluster region is about 1:4, with themost distant objects concentrated in the western half. The filamentarystructure of the spiral population and its orientation are alsoreflected by the H I-deficient objects alone. The H I deficiency patternshows a central enhancement extending from ~16 to 22 Mpc inline-of-sight distance; most of this enhancement arises from galaxiesthat belong to the Virgo cluster proper. However, significant gasdeficiencies are also detected outside the main body of the cluster in aprobable group of galaxies at line-of-sight distances ~25-30 Mpc, lyingin the region dominated by the southern edge of the M49 subcluster andclouds W' and W, as well as in various foreground galaxies. In the Virgoregion, the H I content of the galaxies then is not a straightforwardindicator of cluster membership.
| The UZC-SSRS2 Group Catalog
We apply a friends-of-friends algorithm to the combined Updated ZwickyCatalog and Southern Sky Redshift Survey to construct a catalog of 1168groups of galaxies; 411 of these groups have five or more members withinthe redshift survey. The group catalog covers 4.69 sr, and all groupsexceed the number density contrast threshold, δρ/ρ=80. Wedemonstrate that the groups catalog is homogeneous across the twounderlying redshift surveys; the catalog of groups and their membersthus provides a basis for other statistical studies of the large-scaledistribution of groups and their physical properties. The medianphysical properties of the groups are similar to those for groupsderived from independent surveys, including the ESO Key Programme andthe Las Campanas Redshift Survey. We include tables of groups and theirmembers.
| Hα surface photometry of galaxies in the Virgo cluster. IV. The current star formation in nearby clusters of galaxies
Hα +[NII] imaging observations of 369 late-type (spiral) galaxiesin the Virgo cluster and in the Coma/A1367 supercluster are analyzed,covering 3 rich nearby clusters (A1367, Coma and Virgo) and nearlyisolated galaxies in the Great-Wall. They constitute an opticallyselected sample (mp<16.0) observed with ~ 60 %completeness. These observations provide us with the current(T<107 yrs) star formation properties of galaxies that westudy as a function of the clustercentric projected distances (Theta ).The expected decrease of the star formation rate (SFR), as traced by theHα EW, with decreasing Theta is found only when galaxies brighterthan Mp ~ -19.5 are considered. Fainter objects show no orreverse trends. We also include in our analysis Near Infrared data,providing information on the old (T>109 yrs) stars. Puttogether, the young and the old stellar indicators give the ratio ofcurrently formed stars over the stars formed in the past, or``birthrate'' parameter b. For the considered galaxies we also determinethe ``global gas content'' combining HI with CO observations. We definethe ``gas deficiency'' parameter as the logarithmic difference betweenthe gas content of isolated galaxies of a given Hubble type and themeasured gas content. For the isolated objects we find that b decreaseswith increasing NIR luminosity. In other words less massive galaxies arecurrently forming stars at a higher rate than their giant counterpartswhich experienced most of their star formation activity at earliercosmological epochs. The gas-deficient objects, primarily members of theVirgo cluster, have a birthrate significantly lower than the isolatedobjects with normal gas content and of similar NIR luminosity. Thisindicates that the current star formation is regulated by the gaseouscontent of spirals. Whatever mechanism (most plausibly ram-pressurestripping) is responsible for the pattern of gas deficiency observed inspiral galaxies members of rich clusters, it also produces the observedquenching of the current star formation. A significant fraction of gas``healthy'' (i.e. with a gas deficiency parameter less than 0.4) andcurrently star forming galaxies is unexpectedly found projected near thecenter of the Virgo cluster. Their average Tully-Fisher distance isfound approximately one magnitude further away (muo = 31.77)than the distance of their gas-deficient counterparts (muo =30.85), suggesting that the gas healthy objects belong to a cloudprojected onto the cluster center, but in fact lying a few Mpc behindVirgo, thus unaffected by the dense IGM of the cluster. Based onobservations taken at the Observatorio Astronómico Nacional(Mexico), the OHP (France), Calar Alto and NOT (Spain) observatories.Table \ref{tab4} is only available in electronic form athttp://www.edpsciences.org
| Distances to 24 Galaxies in the Direction of the Virgo Cluster and a Determination of the Hubble Constant
To study the spatial distribution of galaxies lying between the Virgocluster and the Local Group, a search was made for probable nearbygalaxies. Using the method of brightest stars and of blue and redsupergiants made it possible to determine the distances to 24 galaxies,among which six relatively nearby galaxies were identified. The resultsof the distance determinations showed that the maximum in the numberdistribution of galaxies lies at 17.0 Mpc, which we take as the distanceto the Virgo cluster. Using the difference between the distance moduliof two clusters of galaxies, in Virgo and Coma Berenices, fromliterature sources and the velocity of the latter cluster, we determinedthe Hubble constant to be H 0 = 77 ± 7km·sec-1·Mpc-1.
| HI observations of nearby galaxies . I. The first list of the Karachentsev catalog
We present HI observations of the galaxies in the first list of theKarachentsev catalog of previously unknown nearby dwarf galaxies(Karachentseva & Karachentsev 1998). This survey covers all knownnearby galaxy groups within the Local Volume (i.e. within 10 Mpc) andtheir environment, that is about 25% of the total sky. A total of 257galaxies have been observed with a detection rate of 60%. We searched afrequency band corresponding to heliocentric radial velocities from -470km s-1 to ~ +4000 km s-1. Non-detections areeither due to limited coverage in radial velocity, confusion with LocalHI (mainly in the velocity range -140 km s-1 to +20 kms-1), or lack of sensitivity for very weak emission. 25% ofthe detected galaxies are located within the Local Volume. Thosegalaxies are dwarf galaxies judged by their optical linear diameter (1.4+/- 0.2 kpc on the average), their mean total HI mass (4.6107 Msun), and their observed linewidths (39 kms-1).
| 1.65 μm (H-band) surface photometry of galaxies. V. Profile decomposition of 1157 galaxies
We present near-infrared H-band (1.65 μm) surface brightness profiledecomposition for 1157 galaxies in five nearby clusters of galaxies:Coma, A1367, Virgo, A262 and Cancer, and in the bridge between Coma andA1367 in the ``Great Wall". The optically selected (mpg≤16.0) sample is representative of all Hubble types, from E to Irr+BCD,except dE and of significantly different environments, spanning fromisolated regions to rich clusters of galaxies. We model the surfacebrightness profiles with a de Vaucouleurs r1/4 law (dV), withan exponential disk law (E), or with a combination of the two (B+D).From the fitted quantities we derive the H band effective surfacebrightness (μe) and radius (re) of each component, theasymptotic magnitude HT and the light concentration indexC31. We find that: i) Less than 50% of the Ellipticalgalaxies have pure dV profiles. The majority of E to Sb galaxies is bestrepresented by a B+D profile. All Scd to BCD galaxies have pureexponential profiles. ii) The type of decomposition is a strong functionof the total H band luminosity (mass), independent of the Hubbleclassification: the fraction of pure exponential decompositionsdecreases with increasing luminosity, that of B+D increases withluminosity. Pure dV profiles are absent in the low luminosity rangeLH<1010 L\odot and become dominantabove 1011 L\odot . Based on observations taken atTIRGO, Gornergrat, Switzerland (operated by CAISMI-CNR, Arcetri,Firenze, Italy) and at the Calar Alto Observatory (operated by theMax-Planck-Institut für Astronomie (Heidelberg) jointly with theSpanish National Commission for Astronomy). Table 2 and Figs. 2, 3, 4are available in their entirety only in electronic form at the CDS viaanonymous 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.
| Internal extinction, population incompleteness bias and the faint-end of the B-band Tully-Fisher relation
We analyse the distribution of three different samples of spiralgalaxies of the Local Universe in the B-band luminosity-maximumrotational velocity (L_B-VMax) plane, i.e. the B-magnitudeTully-Fisher (TF) relation. The first sample comprises 25+31 late-type(from Sa to Im-BCD) galaxies, selected from, respectively, the Virgo andthe Ursa Major clusters. In addition, a sample of 20 group extremelate-type (ELT) spiral (from Sd to Sm) galaxies and a sample of 13 dwarflate-type galaxies are selected. First, we analyse the influence ofthree different corrections for internal extinction (IE) on both theslope and the zero-point of the relation. These recipes reflect eitheri) the morphological type dependence of the IE or ii) the assumption ofa ``sandwich-model'' for the distribution of the dust and the stellarcomponents within the disk or iii) the existence of the metallicity-massrelation. As a first result we find that the latter recipe of IEcorrection systematically makes Sa-Sc galaxies brighter than laterspirals. Since the former galaxies mainly populate the region of thebright, fast rotators, the slope of the corresponding TF relationbecomes much steeper than in the other two cases. Under the hypothesisthat the ELT spiral galaxies in clusters and in groups share the sameLF, we show that the claimed skew of the group ELT spiral galaxies withrespect to the extrapolated TF relation of more luminous systems (i.e.the local TF calibrators) is due both to the population incompletenessbias affecting such a template and to the type segregation. Finally, weconfirm that the distribution of dwarf galaxies with comparablerotational and random velocities in the L_B-VMax plane isconsistent with the relation of more luminous systems, while therotationally supported dwarf galaxies are underluminous with respect tothe ELT galaxies of the same VMax. However, the latterresults may suffer from the heterogeneous methods of measurement ofdwarf galaxy distances that were adopted.
| A linear near-IR Tully-Fisher relation for giant and dwarf late-type galaxies
We present the near-IR (K(') -band, i.e.: lambda = 2.1 ^mu m)Tully-Fisher (TF) relation for a sample of 50 giant and dwarf late-typegalaxies, selected from the Virgo Cluster Catalogue. We find that L ~VMax(4) along a range of 8 K(') -mag for galaxies withdifferent Hubble types (from Sa to Im-BCD), phenomenologies, structures,star-formation histories, masses, dark-to-luminous mass ratios,metallicities and, perhaps, ages. The linearity of the near-IR TFrelation is in contrast with recent determinations of the optical TFrelations for samples of extreme late-type and dwarf galaxies. Thenear-IR TF law is in agreement both with the expectation from theFundamental Plane for disk systems and with the scenario ofself-regulating star-formation in disks. The previous results suggestthat the TF relation reflects the connection between thestructural/dynamical properties and the star-formation process of bothgiant and dwarf late-type galaxies, through a gas supply forstar-formation regulated by the gravitational potential of the galaxy.
| A Complete Redshift Survey to the Zwicky Catalog Limit in a 2^h X 15 deg Region around 3C 273
We compile 1113 redshifts (648 new measurements, 465 from theliterature) for Zwicky catalog galaxies in the region (-3.5d <= delta<= 8.5d, 11h5 <= alpha <= 13h5). We include redshifts for 114component objects in 78 Zwicky catalog multiplets. The redshift surveyin this region is 99.5% complete to the Zwicky catalog limit, m_Zw =15.7. It is 99.9% complete to m_Zw = 15.5, the CfA Redshift Survey(CfA2) magnitude limit. The survey region is adjacent to the northernportion of CfA2, overlaps the northernmost slice of the Las CampanasRedshift Survey, includes the southern extent of the Virgo Cluster, andis roughly centered on the QSO 3C 273. As in other portions of theZwicky catalog, bright and faint galaxies trace the same large-scalestructure.
| The Virgo Cluster Distance from 21 Centimeter Line Widths
The distance of the Virgo cluster is derived in the B band from the 21cm line width-absolute magnitude relation. This relation is calibratedusing 18 spirals with Cepheid distances, mainly from the Hubble SpaceTelescope. The calibration is applied to a complete sample ofnonpeculiar spirals with i > 45 deg lying within the optical (n = 49)or X-ray (n = 35) contour of the cluster, resulting in a mean clusterdistance of (m - M)0 = 31.58 +/- 0.24 mag (external error), or 20.7 +/-2.4 Mpc. The mean distance of subcluster A is 0.46 +/- 0.18 mag smallerthan that of subcluster B, but the individual distances of the membersof the two substructures show considerable overlap. Cluster spirals with30 deg < i < 45 deg yield distances almost as good as those ofmore inclined galaxies. H I-truncated galaxies are overluminous by 0.8mag at a given line width. The distance modulus is corrected by -0.07mag for the fact that cluster members have lower H I surface fluxes andare redder in (B-I) at a given line width than the (field) calibrators.Different sources for the B magnitudes and line widths have littleeffect on the resulting distance. Different precepts for the internalabsorption correction change the result by no more than +/-0.17 mag. Theindividual distances of the cluster members do not show any dependenceon recession velocity, inclination, Hubble type, or line width. Thedependence on apparent magnitude reflects the considerable depth effectof the cluster. The adopted distance is in good agreement withindependent distance determinations of the cluster. Combining thecluster distance with the corrected cluster velocity of 1142 +/- 61 kms-1 gives H0 = 55 +/- 7 km s-1 Mpc-1 (external error). If the Virgocluster distance is inserted into the tight Hubble diagram of clustersout to 11,000 km s-1 using relative distances to the Virgo cluster, oneobtains a global value of H0 = 57 +/- 7 km s-1 Mpc-1.
| A list of new nearby dwarf galaxy candidates
To increase completeness of the distance limited sample of nearbygalaxies from the \cite[Kraan-Korteweg & Tammann (1979)]{Kra79}catalogue we undertook a search for small companions of larger knowngalaxies which have corrected radial velocities within 500 km/s. Basedprimarily on the POSS-II and ESO/SERC films we found 260 nearby dwarfgalaxy candidates with angular diameters aga0 .5 arcmin. More than 50%of the objects were revealed for the first time. As we suppose, asignificant part of them (about 30%) may really belong to the LocalVolume sample. Tables 1 and 2 also available in electronic form at CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via\breakftp://cdsweb.u-strasbg.fr/Abstract.html
| FAUST Observations of Ultraviolet Sources toward the Virgo Cluster
We analyze three UV images covering a ~100 square degree field towardthe Virgo cluster, obtained by the FAUST space experiment. We detect 191sources to a signal-to-noise ratio of 4.4 and identify 94% of them. Mostsources have optical counterparts in existing catalogs, and about halfare identified as galaxies. Some sources with no listed counterpart wereobserved at the Wise Observatory. We present the results oflow-resolution visible spectrophotometry and discuss the foreground 101stellar sources and the 76 detected galaxies, both in the cluster and inthe foreground or background. We derive conclusions on star formationproperties of galaxies and on the total UV flux from discrete anddiffuse sources in the cluster. We test for the presence of intraclusterdust, determine the clustering properties of UV emitting galaxies, andderive the UV luminosity function of Virgo galaxies.
| Study of the Virgo Cluster Using the B-Band Tully-Fisher Relation
The distances to spiral galaxies of the Virgo cluster are estimatedusing the B-band Tully-Fisher (TF) relation, and the three-dimensionalstructure of the cluster is studied. The analysis is made for a completespiral sample taken from the Virgo Cluster catalog of Binggeli, Sandage,& Tammann. The sample contains virtually all spiral galaxies down toM_{BT}=-15 mag at 40 Mpc. A careful examination is made ofthe selection effect and errors of the data. We estimate distance to 181galaxies, among which distances to 89 galaxies are reasonably accurate.We compare these distances to those obtained by other authors on agalaxy-by-galaxy basis. We find reasonable consistency of theTully-Fisher distance among various authors. In particular, it is foundthat the discrepancy in the distance among the different analyses withdifferent data is about 15%, when good H I and photometric data areavailable. We clarify that the different results on the Virgo distanceamong authors arise from the choice of the sample and interpretation ofthe data. We confirm that the Tully-Fisher relation for the Virgocluster shows an unusually large scatter sigma = 0.67 mag, compared tothat for other clusters. We conclude that this scatter is not due to theintrinsic dispersion of the Tully-Fisher relation, but due to a largedepth effect of the Virgo cluster, which we estimate to be extended from12 Mpc to 30 Mpc. The distribution of H I--deficient galaxies isconcentrated at around 14--20 Mpc, indicating the presence of a core atthis distance, and this agrees with the distance estimated for M87 andother elliptical galaxies with other methods. We show also that thespatial number density of spiral galaxies takes a peak at this distance,while a simple average of all spiral galaxy distances gives 20 Mpc. Thefact that the velocity dispersion of galaxies takes a maximum at 14--18Mpc lends an additional support for the distance to the core. Thesefeatures cannot be understood if the large scatter of the TF relation ismerely due to the intrinsic dispersion. The structure of the VirgoCluster we infer from the Tully-Fisher analysis looks like a filamentwhich is familiar to us in a late phase of structure formation in thepancake collapse in hierarchical clustering simulations. This Virgofilament lies almost along the line of sight, and this is the originthat has led a number of authors to much confusion in the Virgo distancedeterminations. We show that the M87 subcluster is located around 15--18Mpc, and it consists mainly of early-type type spiral galaxies inaddition to elliptical and S0 galaxies. There are very few late-typespiral galaxies in this subcluster. The spiral rich M49 subclusterconsists of a mixture of all types of spiral galaxies and is located atabout 22 Mpc. The two other known clouds, W and M, are located at about30--40 Mpc and undergo infall toward the core. The M cloud contains fewearly type spirals. We cannot discriminate, however, whether thesesubclusters or clouds are isolated aggregates or merely parts offilamentary structure. Finally, we infer the Hubble constant to be 82+/- 10 km s-1 Mpc-1.
| Near infrared surface photometry of late-type Virgo cluster galaxies
Near Infrared (K' band) surface photometry has been obtained for 102 (88late-type) Virgo cluster galaxies. A subset of 20 galaxies was alsoimaged in the H band. Magnitudes and diameters within the 21.5 and 22.0mag arcsec$^{-2}$ isophote, concentration indices and total H and K'magnitudes are derived. Basic statistical properties of a completesample of spiral galaxies spanning the range 6.3 < K'_T < 13.5 aregiven. Tables 3, 5 and 6 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html} Based on observations taken atthe Calar Alto Observatory, operated by the Max-Planck-Institut furAstronomie (Heidelberg) jointly with the Spanish National Commission forAstronomy.
| Arecibo H i Mapping of a Large Sample of Dwarf Irregular Galaxies
Neutral hydrogen mapping of 70 dwarf irregular (Sm, Im, and BCD)galaxies is reported, with position-velocity contour maps (and a fewcontour maps in R.A. and decl.) presented for those resolved by theArecibo beam. The galaxies were selected either from the Virgo ClusterCatalog, from similarly identified field galaxies, or from a distance-limited sample within the Arecibo declination range. We do not find anyisolated dwarfs with a larger H I to optical radius ratio than DDO 154;the "protogalaxy" H I 1225+01 of Giovanelli & Haynes continues to bea unique object among dwarfs that have been mapped in H I. For alldwarfs with significant rotation, we are able to determine the sense ofthe spin. For a number of better resolved dwarfs, we are able todetermine rotation curves, in most cases extending well beyond the lastmeasured point in available synthesis array maps. Correlations among theseveral measures of galaxy size and mass are studied; in a companionpaper we combine these data with those for the set of all availablemapped dwarf irregular galaxies and for mapped spirals spanning asimilar range of redshifts to investigate variations in Tully-Fisherrelations and in surface densities as functions of galaxy size andluminosity or mass.
| A catalog of far-ultraviolet point sources detected with the fast FAUST Telescope on ATLAS-1
We list the photometric measurements of point sources made by the FarUltraviolet Space Telescope (FAUST) when it flew on the ATLAS-1 spaceshuttle mission. The list contains 4698 Galactic and extragalacticobjects detected in 22 wide-field images of the sky. At the locationssurveyed, this catalog reaches a limiting magnitude approximately afactor of 10 fainter than the previous UV all-sky survey, TDl. Thecatalog limit is approximately 1 x 10-14 ergs A sq cm/s,although it is not complete to this level. We list for each object theposition, FUV flux, the error in flux, and where possible anidentification from catalogs of nearby stars and galaxies. Thesecatalogs include the Michigan HD (MHD) and HD, SAO, the HIPPARCOS InputCatalog, the Position and Proper Motion Catalog, the TD1 Catalog, theMcCook and Sion Catalog of white dwarfs, and the RC3 Catalog ofGalaxies. We identify 2239 FAUST sources with objects in the stellarcatalogs and 172 with galaxies in the RC3 catalog. We estimate thenumber of sources with incorrect identifications to be less than 2%.
| Surface photometry of spiral galaxies in the Virgo cluster region
Photographic surface photometry is carried out for 246 spiral galaxiesin the Virgo cluster region north of declination + 5 deg. The samplecontains all spiral galaxies of 'certain' and 'possible' Virgo membersin the Virgo Cluster Catalogue of Binggeli, Sandage, & Tammann. Thesample also includes those galaxies which were used in the Tully-Fisheranalyses of the Virgo cluster given in the literature. A catalog ispresented for positions, B-band total magnitudes and inclinations forthese galaxies, and they are compared with the data given in previousstudies.
| Ultraviolet observations of galaxies with the FAUST experiment
We have used the set of point sources detected by the Far UltravioletSpace Telescope (FAUST) instrument to identify galaxies and study thetotal galaxy flux in a 250 A wide band peaking at 1650 A. A sample of144 galaxies has been obtained after cross-reference with the RC3catalog, elimination of objects confused with stars and variouscorrections for the photometry. The UV-B color dispersion is found toincrease while the galaxies get redder from late to early types. Theirregular galaxies appear on average redder and the Sbc galaxies bluerthan indicated by the spectral energy distributions currently used forthe calculations of K-corrections. Various arguments lead us to make theassumption of a constant dust extinction within each galaxy. The UV fluxper unit area decreases on average from late to early type spirals. Wefind a weak correlation between the UV and far infra-red emission whilethe infra-red to UV flux ratio gets lower when galaxies get bluer (asmeasured by the UV to B flux ratio). The UV flux per unit areacorrelates with the HI gas surface density and the total gas surfacedensity when this quantity is available. The correlation with themolecular gas alone is weak. In the Virgo cluster, the UV flux per unitarea does not decrease in direct proportion to the HI deficiency. Galaxycounts per square degree and per magnitude interval have been obtainedat high-galactic latitudes. Combined with data at fainter magnitudes,they show a variation as a function of magnitude with a near-euclideanslope over a range of 8 magnitudes.
| Distribution of the spin vectors of the disk galaxies of the Virgo cluster. I. The catalogue of 310 disk galaxies in the Virgo area.
Not Available
| General study of group membership. II - Determination of nearby groups
We present a whole sky catalog of nearby groups of galaxies taken fromthe Lyon-Meudon Extragalactic Database. From the 78,000 objects in thedatabase, we extracted a sample of 6392 galaxies, complete up to thelimiting apparent magnitude B0 = 14.0. Moreover, in order to considersolely the galaxies of the local universe, all the selected galaxieshave a known recession velocity smaller than 5500 km/s. Two methods wereused in group construction: a Huchra-Geller (1982) derived percolationmethod and a Tully (1980) derived hierarchical method. Each method gaveus one catalog. These were then compared and synthesized to obtain asingle catalog containing the most reliable groups. There are 485 groupsof a least three members in the final catalog.
| The kinematics of the Virgo cluster revisited
The paper updates the velocity data of Virgo cluster galaxies andreconsiders the kinematic structure of the Virgo cluster. New velocitiesare given for 144 galaxies listed in the Virgo Cluster Catalog (VCC).Improved velocities are given for another 131 VCC galaxies. The Virgocluster is disentangled from its surrounding clouds of galaxies, and thelikely members of each of these clouds are listed. The velocitydistribution of dwarf elliptical cluster members is found to be highlyasymmetric. This phenomenon is interpreted as evidence for the imminentmerging of two subclusters in the core region, which points to thedynamical youth of the Virgo cluster. The mean heliocentric velocity ofthe Virgo cluster is estimated at 1050 +/- 35 km/s.
| The extragalactic distance scale. II - The unbiased distance to the Virgo Cluster from the B-band Tully-Fisher relation
The behavior of the B-band Tully-Fisher (TF) relation with respect tothe observational biases and parameter uncertainties is studied from analmost complete sample of spiral galaxies belonging to the VirgoCluster. The strong influence of the limiting apparent magnitude whenusing the direct TF relation is confirmed. A distance modulus of 31.4 +or - 0.2 is found along with a corresponding H(0) = 68 + or - 8km/s/Mpc, assuming a cosmological velocity of the cluster V = 1300 + or- 100 km/s. The Virgo S and S-prime clouds are shown to lie atsignificantly different distances. Different distance moduli found byother authors are explained.
| Imaging and spectrophotometry of Virgo cluster irregular galaxies
Large-aperture spectrophotometric observations and CCD images in theH-alpha and R bands have been obtained for Virgo cluster Magellanic,dwarf, and amorphous irregular galaxies. Although a small number ofVirgo cluster irregulars have optical and H I properties consistent withrecent gas loss, the rate of production of gas-poor irregulars is toolow to account for the large population of Virgo cluster dE galaxies orto explain the deficiency in the number of irregulars relative tospirals. Radial brightness profiles reveal that only NGC 4641 followsthe r exp 1/4 law of classical ellipticals, that four of the galaxieshave exponential brightness distributions, and that one system has anindeterminant profile form. It is shown that the properties of Virgocluster irregular galaxies can be best understood in terms ofenvironmental modifications of normal systems in the circumclusterenvironment and in the cluster core.
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