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Molecular gas in compact galaxies
New observations of eleven compact galaxies in the 12CO J =2{-}1 and J = 3{-}2 transitions are presented. From these observationsand literature data accurate line ratios in matched beams have beenconstructed, allowing the modelling of physical parameters. Matching asingle gas component to observed line ratios tends to produce physicallyunrealistic results, and is often not possible at all. Much betterresults are obtained by modelling two distinct gas components. In mostobserved galaxies, the molecular gas is warm (Tk = 50{-}150K) and at least partially dense (n(H2) ≥ 3000cm-3). Most of the gas-phase carbon in these galaxies is inatomic form; only a small fraction ( 5%) is in carbon monoxide.Beam-averaged CO column densities are low (of the order of1016 cm-2). However, molecular hydrogen columndensities are high (of the order of 1022 cm-2)confirming large CO-to- H2 conversion factors (typically X =1021{-}1022 cm-2/ {K kms-1}) found for low-metallicity environments by othermethods. From CO spectroscopy, three different types of molecularenvironment may be distinguished in compact galaxies. Type I (highrotational and isotopic ratios) corresponds to hot and dense molecularclouds dominated by star-forming regions. Type II has lower ratios,similar to the mean found for infrared-luminous galaxies in general, andcorresponds to environments engaged in, but not dominated by,star-forming activity. Type III, characterized by low 12CO(2-1)/(1-0) ratios, corresponds to mostly inactive environments ofrelatively low density.
| Cold dust and molecular gas towards the centers of Magellanic type galaxies and irregulars. I. The data
We present 1300 μm continuum emission measurements and observationsof the 12CO (1-0) and (2-1) transition towards the centers of64 Magellanic type galaxies (Sdm/Sm) and irregulars (Im/I0/Irr). Thesources are selected to have IRAS flux densities S100 μm≥1000 mJy and optical diameters mainly below 180 arcsec. We wereable to detect 12CO towards 41 and the continuum emissiontowards 28 galaxies. In addition, we obtained the corresponding data fora set of 6 complementary galaxies of different morphological type.Based on observations collected at ESO, La Silla, Chile and IRAM, PicoVeleta, Spain.The full version of Figs. \ref{spec1.fig} and \ref{spec2.fig} is onlyavailable in electronic form at http://www.edpsciences.org
| Tidally Triggered Star Formation in Close Pairs of Galaxies. II. Constraints on Burst Strengths and Ages
Galaxy-galaxy interactions rearrange the baryons in galaxies and triggersubstantial star formation; the aggregate effects of these interactionson the evolutionary histories of galaxies in the universe are poorlyunderstood. We combine B- and R-band photometry and optical spectroscopyto estimate the strengths and timescales of bursts of triggered starformation in the centers of 190 galaxies in pairs and compact groups.Based on an analysis of the measured colors and EW(Hα), wecharacterize the preexisting and triggered populations separately. Thebest-fitting burst scenarios assume stronger reddening corrections forline emission than for the continuum and continuous star formationlasting for >~100 Myr. The most realistic scenarios require aninitial mass function that is deficient in the highest mass stars. Thecolor of the preexisting stellar population is the most significantsource of uncertainty. Triggered star formation contributessubstantially (probably >~50%) to the R-band flux in the centralregions of several galaxies; tidal tails do not necessarily accompanythis star formation. Many of the galaxies in our sample have bluercenters than outskirts, suggesting that pre- or nonmerger interactionsmay lead to evolution along the Hubble sequence. These objects wouldappear blue and compact at higher redshifts; the older, redder outskirtsof the disks would be difficult to detect. Our data indicate thatgalaxies with larger separations on the sky contain weaker, and probablyolder, bursts of star formation on average. However, confirmation ofthese trends requires further constraints on the colors of the olderstellar populations and on the reddening for individual galaxies.
| The 1.0 Megaparsec Galaxy Pair Sample in Low-Density Regions
Using complete redshift catalogs, we have compiled a list of galaxypairs based solely on a pair's projected separation, rp, andvelocity difference, ΔV. We have made high-velocity precision H Iobservations of each galaxy in the sample and have reported these in theliterature. Due to the nature of the redshift catalogs, we are able toquantitatively evaluate the effects of isolation and number density ofsurrounding galaxies on each pair in the sample. For the close galaxypairs (rp<100 kpc), the degree of isolation (a measure ofthe number of near neighbors) has little effect on the median ΔV.This median is about 55 km s-1 for the 25 close pairs (ifmedium-density close pairs are omitted ΔV is even smaller, but thedifference is not statistically significant). The effect of isolation isstrong for the entire sample of galaxy pairs with separations as largeas 1.0 Mpc. For these larger separation pairs, relaxation of strictisolation requirements introduces small groups into the sample, whichdramatically increases the median ΔV. We find little evidence ofan increase in the median ΔV with decreasing rp, norwith increasing total luminosity. For our isolated pairs in low-densityregions, the overall median ΔV is only 30 km s-1. Forsimilar separations and isolation criteria, galaxy satellites withlarger luminosity ratios (i.e., less dynamical friction) in higherdensity regions have ΔV approximately twice as large. Weconjecture that our orbits are highly eccentric, so that the indirecteffect of dynamical friction leads to predominantly small ΔV.However, the halos of our galaxies may also be of low density (althoughhighly extended).
| 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.
| The second KISO Survey for ultraviolet-excess galaxies. I
Not Available
| Disk Galaxies in the Outer Local Supercluster: Optical CCD Surface Photometry and Distribution of Galaxy Disk Parameters
We report new B-band CCD surface photometry on a sample of 76 diskgalaxies brighter than B_T = 14.5 mag in the Uppsala General Catalogueof Galaxies that are confined within a volume located in the outer partof the Local Supercluster. With our earlier published I-band CCD andhigh signal-to-noise ratio 21 cm H I data, this paper completes ouroptical surface photometry campaign on this galaxy sample. As anapplication of this data set, the B-band photometry is used here toillustrate two selection effects that have been somewhat overlooked inthe literature but that may be important in deriving the distributionfunction of disk central surface brightness (CSB) of disk galaxies froma diameter- and/or flux-limited sample: a Malmquist-type bias againstdisk galaxies with small disk scale lengths (DSLs) at a given CSB and adisk inclination-dependent selection effect that may, for example, biastoward inclined disks near the threshold of a diameter-limited selectionif disks are not completely opaque in the optical. Taking intoconsideration these selection effects, we present a method ofconstructing a volume-sampling function and a way to interpret thederived distribution function of CSB and DSL. Application of this methodto our galaxy sample implies that if galaxy disks are optically thin,CSB and DSL may well be correlated in the sense that, up to aninclination-corrected limiting CSB of about 24.5 mag arcsec^-2 that isadequately probed by our galaxy sample, the DSL distribution of galaxieswith a lower CSB may have a longer tail toward large values unless thedistribution of disk galaxies as a function of CSB rises rapidly towardfaint values.
| Groups of galaxies. III. Some empirical characteristics.
Not Available
| 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
| Kinematics of the local universe. VII. New 21-cm line measurements of 2112 galaxies
This paper presents 2112 new 21-cm neutral hydrogen line measurementscarried out with the meridian transit Nan\c cay radiotelescope. Amongthese data we give also 213 new radial velocities which complement thoselisted in three previous papers of this series. These new measurements,together with the HI data collected in LEDA, put to 6 700 the number ofgalaxies with 21-cm line width, radial velocity, and apparent diameterin the so-called KLUN sample. Figure 5 and Appendices A and B forcorresponding comments are available in electronic form at thehttp://www.edpsciences.com
| 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
| Influence of a partial incompleteness of the sample on the determination of the Hubble constant.
This paper presents a study of the Malmquist bias effect in thedetermination of the Hubble constant from the method of "sosies"(look-alike) galaxies. It is shown that a bias appears when a partialincompleteness exists in the sample. A new method, based on the use ofthe completeness curve, is proposed to correct for such a bias. Afterthis correction, the Hubble constant drops of about 20% just because ofthe existence of the partial incompleteness. From the present resultsand on the acceptance of the distance modulus of primary calibrators,the value of the Hubble constant would be: H_0_=~60km/s/Mpc with aninternal statistical error of about 2km/s/Mpc.
| Rotation Curves and Velocity Measures for Spiral Galaxies in Pairs
Rotation curves have been obtained for 76 spiral galaxies in pairs,including a geometrically selected subset from the Karachentsev catalogand a set of Seyfert galaxies with close companions. Derived parametersof the rotation curves and the galaxies light distributions are alsopresented. The rotation curves are classified broadly by shape, withspecial emphasis on kinematic disturbances and regions of solid-bodybehavior that may lead to bar development. Broadband images of thegalaxies allow assessments of their degree of symmetry or disturbance.These velocity slices afford an empirical basis for evaluating theaccuracy of radial velocity measures for spiral galaxies in pairs, andthe dynamically important radial velocity differences. Specifically, thedisagreement among several plausible ways of estimating the centralvelocity from these rotation data is used to estimate how closely any ofthese might approximate the nuclear or center-of-mass values. From sevenindicators of central velocity, the internal scatter is σ_vv_ = 34km s^-1^. Of these, the velocity weighted by Hα intensity alongthe slit shows a systematic offset of about 20 km s^-1^ with respect tothe others for the Karachentsev pairs, in the sense that this measure isredshifted with respect to the other indicators. This is in the sense(but not of the total magnitude) required to account for statisticalasymmetries in pair velocity differences. Individual scatter between thevelocity indicators taken pairwise ranges from σ = 20 to 52 km s^-1^. These results imply that emission-line data such as these cannotspecify the center of mass or nuclear redshift at a level more accuratethan this, even for arbitrarily precise velocity measurements, becauseit is not clear how the observed quantities relate to the desiredmeasurement in a physical sense. No useful predictor of which galaxieshave large or small scatter among velocity measures was found, exceptthat the scatter is small for the class of "nonrotating" galaxies withsmall overall velocity amplitudes. Projected separation, separationnormalized to disk scale length, and morphological disturbance do notcorrelate with the velocity scatter.
| A Minnesota Automated Plate Scanner Catalog of Galaxies behind the Virgo Cluster and toward Its Antipode
We present a catalog of 1268 galaxies, essentially complete to B <=17.0, found by scanning glass copies of several fields of the originalPalomar Sky Survey using the Minnesota Automated Plate Scanner in itsisodensitometric mode (as opposed to the threshold densitometric modeused in the APS Catalog of the POSS I). In addition to the differentscanning mode, we have employed a different star-galaxy separationmethod and have visually inspected POSS prints to verify that each imageremaining in the catalog is nonstellar. The scanned fields aredistributed generally in two areas, one around the outskirts of theVirgo Cluster, the other toward the antipode of the cluster (but stillin the northern celestial hemisphere). The catalog gives the position ofthe center of each galaxy; estimates of the blue and red magnitudeswithin the outermost threshold crossing and of the blue magnitudeextrapolated to zero surface brightness; and the blue and red diametersof four ellipses fitted to the four threshold crossings (approximately23.8,23.6,23.2, and 22.7 mag arcsec 2 in blue, and 22.5,22.4,21.5, and21.2 mag arcsec^-2^ in red), and the ellipticities of those fourellipses. The catalog has served as a base from which to draw targetsfor a Tully-Fisher study of the Virgocentric infall velocity of theLocal Group.
| Galaxy Pairs, Redshift Catalogs, and the Cosmic Peculiar Velocity
We discuss pairs of spiral galaxies with projected separations r_p_ranging from very wide (r_p_ ~ 1.0 Mpc) to very small (r_p_ <~ 75kpc). Single-dish H I data for the wide pairs and H I aperture synthesisas well as CCD images for the close pairs were presented in earlierpapers. From pairs (regardless of isolation criteria) in redshiftcatalogs, we find that the kinematics of spiral-spiral pairs inlow-density regions is qualitatively different from that in high-densityregions. The velocity distribution function f({DELTA}V) in low-densityregions has two components: (i) a narrow component (which is related toisolated pairs) with a very small rms value σ_v,n_ of the"one-dimensional random cosmic peculiar velocity" δν, and (ii)a broad, slowly decreasing component (which is related to pairs in loosegroups) with a large rms value of the "one-dimensional random cosmicpeculiar velocity" σnu,b_. Thus, we confirm that thedistribution of the "one- dimensional cosmic peculiar velocity"{DELTA}ν is not Gaussian and its rms value σ_V_ varies withenvironment. The median {DELTA}V_med_ of the absolute value of thevelocity difference of isolated wide pairs is ~30 km s^-1^, considerablysmaller than all estimates of σ_v_. This small {DELTA}V_med_suggests that the pairs are on low total energy, almost radial orbits,and it is also a constraint on cosmological models of structureformation. We find some circumstantial evidence for a negativecorrelation between the peculiar velocity δν and thedifferential Hubble flow velocity {DELTA}V_H_ which would be the casefor bound orbits near the maximum separation (" turnaround ``) at thecurrent epoch. If future larger samples (e.g., the CfA2 and the SSRS2surveys) confirm this, then a total galaxy mass ~10^12^ M_sun_ isimplied. All the six close pairs for which we have detailed H I andoptical CCD images show some signs of interaction, even though theselection criteria were specifically independent of known morphologicalpeculiarities. For three of the six pairs there is good evidence for thepairs also being on high eccentricity, low total energy orbits, andthere is some evidence that the impact parameter for one pair is ~1 diskradius. The median velocity difference {DELTA}V_med_ of the close pairssample is also ~30 km s^-1^. This small value of {DELTA}V_med_ isprobably an indirect effect of dynamical friction.
| 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.
| Dynamics of Binary Galaxies. III. Details of the Close Pairs
In a previous paper [Chengalur et al. ApJ, 107, 1984(1994)] H Isynthesis data and CCD images were presented for an objectively chosensample of six close spiral-spiral galaxy pairs. In this paper we presenta detailed analysis of the data. Although the presence of tidal featureswas not an explicit selection criterion, five of our six pairs showtidal tails and bridges. The remaining pair also shows signs ofinteraction: both galaxies in the pair have disturbed velocity fieldsand one of the two galaxies has a central concentration of molecular gasand is undergoing a starburst. The morphology of three of the six pairsimplies that the galaxies are on high eccentricity, low total energyorbits, and for one of these pairs there is some evidence that theimpact parameter is as small as ~1 disk radius. For the remaining threepairs the tidal features are not as pronounced, and the observations donot yield as much information on the orbit. However, even for thesepairs, the observed morphology is consistent with the galaxies being onslow, small impact parameter orbits, provided the galaxies are at arelatively early phase of the orbit, i.e., prior to the first closeencounter. We also find weak evidence for preferential alignment in thepairs (with the lack of preferential alignment being ruled out at the97% level), in the sense that the major axis of a galaxy tends to pointtoward the companion galaxy. This sample of close pairs is complementedby a larger sample of wide pairs (Chengalur et al. 1993). The medianvelocity difference {DELTA}V of the sample of close pairs in low-densityregions is not much different from that for the wide pairs sample, inparticular, there is no evidence for positive energy impacts. The effectof dynamical friction on infall velocities is controversial and will bediscussed in the following paper [Chengalur et al., in preparation(1995)] which combines the data on close and wide pairs.
| Integrated photoelectric magnitudes and color indices of bright galaxies in the Johnson UBV system
The photoelectric total magnitudes and color indices published in theThird Reference Catalogue of Bright Galaxies (RC3) are based on ananalysis of approximately equals 26,000 B, 25,000 B-V, and 17,000 U-Bmultiaperture measurements available up to mid 1987 from nearly 350sources. This paper provides the full details of the analysis andestimates of internal and external errors in the parameters. Thederivation of the parameters is based on techniques described by theVaucouleurs & Corwin (1977) whereby photoelectric multiaperture dataare fitted by mean Hubble-type-dependent curves which describe theintegral of the B-band flux and the typical B-V and U-B integrated colorgradients. A sophisticated analysis of the residuals of thesemeasurements from the curves was made to allow for the random andsystematic errors that effect such data. The result is a homogeneous setof total magnitudes BTA total colors(B-V)T and (U-B)T, and effective colors(B-V)e and (U-B)e for more than 3000 brightgalaxies in RC3.
| Dynamics of binary galaxies. 2: Close pairs
As part of a comprehensive study of binary galaxies, broadband opticalCharge Coupled Device (CCD) images and high resolution H I maps arepresented for six close pairs of spiral galaxies. A previous paperChengalur, et al., (1993) presented the results of a study of binarygalaxies with wide separations. The current sample of close pairs waschosen from the Center for Astrophysics (CfA) redshift catalog usingselection criteria that were objective and completely independent of anypreviously known morphological peculiarities. Nonetheless, all thegalaxies show some sign of interaction, implying that the selectioncriteria were sufficiently well tailored to choose physically associatedparis. All the galaxies show kinematical disturbances and haveasymmetric rotation curves. Tidal tails and bridges are clearly detectedfor some, and two pairs have a large common H I envelope. This common HI envelope also shows a large scale radial velocity gradient and givesthe impression of being in rotation about a single kinematical axis.There is relatively good agreement between the optical and H I images,with similar tidal features being seen in both. The H I features,however, extend to a much larger galactocentric radius than thecorresponding optical features. In at least one case, however, thestellar disk appears relatively normal, while the H I disk appearsdisturbed even towards the center of the galaxy. The systematic velocitydifference for the galaxy pairs has been measured quite accuratelyeither from the integrated H I spectral profile, or from a global fit tothe galaxy velocity fields. The median velocity difference for the sixgalaxy pairs is very small, approximately 20 km/s. Detailed analysis ofthe data will be presented in a separate paper.
| Global properties of dwarf galaxies. I. Galaxy sample and IRAS infrared flux-densities
We have selected a sample of 278 dwarf galaxies for which at least Bmagnitudes and preferably also optical colour information are available.For those galaxies that have no previously published IRAS fluxes, wehave used the IRAS database to extract fluxes or upper limits tosensitivity levels significantly better than those of the IRAS PointSource Catalog. New IRAS data include 79 galaxies detected in at leastone band, and 66 galaxies with good upper limits. In total, about 60% ofall dwarf galaxies in the sample now have been detected at 60/100μm.
| Global properties of dwarf galaxies II. Colours and luminosities
We have used a previously determined sample of 278 dwarf galaxies formost of which B magnitudes, optical colours, HI fluxes and IRASflux-densities are known, in order to derive luminosities, colours andsurface brightnesses. Dwarf galaxy properties are compared to those of acontrol sample of 228 larger spiral galaxies. The dwarf galaxies have onaverage higher 60/100μm flux ratios and lower 12/25μm flux ratiosthan the spiral galaxies, indicating that the contribution of `cirrus'to the infrared emission from dwarf galaxies is relativelyinsignificant. In the dwarf galaxies, the 60/100μm flux ratioincreases with increasing optical blueness; spiral galaxies show theopposite. Dwarf galaxies with a low optical surface brightness have low100μm/HI ratios, but the converse is not true. Galaxies with high100μm/HI ratios (indicative of high dust-to-gas ratios) also havehigh FIR/B ratios as well as high 60/100μm flux-density ratios.Although this is true for both spiral and dwarf galaxies, at given100μm/HI ratios the dwarf galaxies have both a lower FIR/B ratio anda higher 60/100μm flux-density ratio. This result is of importance inthe interpretation of FIR/B - 60/100μm diagrams in terms of starformation activity.
| H I 21 centimeter observations and I-band CCD surface photometry of spiral galaxies behind the Virgo Cluster and toward its antipode
Sample selection, radio and optical data acquisition and reduction, andobservation results are presented for spiral galaxies behind the VirgoCluster and toward its antipode. I-band CCD photometry was obtained forall the bright galaxies and part of the sample of faint galaxies in thetwo local volumes was studied. The statistical properties of the galaxysamples are discussed.
| A revised catalog of CfA1 galaxy groups in the Virgo/Great Attractor flow field
A new identification of groups and clusters in the CfA1 Catalog ofHuchra et al. is presented, using a percolation algorithm to identifydensity enhancements. It is shown that in the resulting catalog,contamination by interlopers is significantly reduced. The Schechterluminosity function is redetermined, including the Malmquist bias.
| Dynamics of Binary Galaxies. I. Wide Pairs
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993ApJ...419...30C&db_key=AST
| Kinematic regulation of star formation in interacting galaxies
Kinematic data for a geometrically-selected set of spiral galaxies inpairs are presented, and analyzed for correlations between indicators ofstar formation and indices of orbital type and extent of kinematicdisturbance. Both nuclear and global star formation rate are connectedto kinematic disturbance with the kind and degree of disturbance moreimportant than either projected separation or relative directions ofgalaxy spin and companion orbit. Enhanced star formation is found forgalaxies with large areas of solid-body rotation and for galaxies withmore general kinds of disturbed velocity structure, with the highestlevels occurring in a set of galaxies distinguished by anomalously smalloverall velocity amplitude. The strongest correlation is between starformation rate (SFR) and amplitude of velocity disturbance, fromrotation curves, when the velocity disturbance is scaled by the galaxyrotation velocity. Triggered star formation is more sensitive to galaxydynamics than to strictly local phenomena such as cloud disruptionvelocities. Comparsion with various models for the enhanced SFR ininteracting systems shows that cloud-collision processes cannot accountfor the strong starbursts in retrograde systems, and models relying oninteractions between different phases of the interstellar mediumsimilarly require too many direct collisions between galaxy disks.Schemes involving gravitational instability of the disk driven initiallyby the external perturbation fare best; such instability can then drivethe rates of other processes such as cloud collisions, possibly in acascadelike series. Solid-body kinematics appear more important than thepresence of a stellar bar in this connection. Using a new set ofclassifications from uniform CCD images, there is a better correlationbetween disturbed kinematics and morphological disturbance of individualgalaxies than with pair interaction types in the Karachentsev catalog,though the relationship is not one-to-one. There is a substantialpopulation of pairs with disturbed kinematics but not disturbed forms.The kinds of disturbance found from direct and retrograde encountersmatch well the predictions of n-body calculations for each kind ofencounter.
| 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.
| Northern dwarf and low surface brightness galaxies. II - The Green Bank neutral hydrogen survey
The paper reports neutral hydrogen observations of a large sample ofdwarf and other low surface brightness galaxies. A detailed discussionand error analysis of the observations are presented, and spectra aredisplayed for 329 galaxies detected for the first time, or detected withsubstantially better signal-to-noise ratios than achieved previously.The positions on the sky of 667 galaxies meeting the present selectioncriteria north of delta = 38 deg are shown. The distribution of theredshifts of galaxies detected at Green Bank is illustrated. The GreenBank detections tapered off strongly below the median H I flux of 3.7 Jykm/s detected at Arecibo: only 12 percent of the Green Bank sample wasdetected with smaller fluxes.
| Cosmology from a galaxy group catalog. I - Binaries
A new, completely objective group-finding algorithm is described andapplied to the CfA redshift catalog. The binary galaxies are isolatedfor analysis. The assumptions underlying the analysis are (1) that lighttraces mass, (2) that our binary galaxy subsets are representative lighttracers, and (3) that the binary orbits are circular. The primary resultof the work is that the resulting bias-free binary catalogs are afunction of the assumed cosmological model. For virtually any inputvalue of Omega(0) in the range 0.01-5.00, there is a reasonablyconsistent interpretation of the CfA survey such that the specifiedvalue of Omega(0) can be derived from the binary sample obtained underthat interpretation. A secondary result is that the higher the inputvalue of Omega(0), the broader the intrinsic distribution in M/L, andhence the less valid the assumption that light traces mass.
| Mass-to-Light Ratios of Binary Galaxies. III. Analysis
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1987ApJS...64..427S&db_key=AST
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