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Studies of an Intergalactic HI Cloud
An intergalactic HI cloud of a few × 109Mȯ, previously detected using the Parkes Radio Telescopeand the Australia Telescope Compact Array (ATCA) (English 1994; Freemanet al. 1996), has been confirmed in further ATCA observations of the NGC3256 galaxy group. The group contains the prominent merging galaxy NGC3256, which is surrounded by a number of HI fragments (English et al.2003), the tidally disturbed galaxy NGC 3263 (Koribalski et al., inprep.), and several other galaxies. Using ATCA HI data we examine thenature of this massive gas cloud and its relationship to theneighbouring galaxies. This could be a primordial ``galaxy buildingblock''. However the cloud's properties, in conjunction with the spatialextents and velocity behaviours of the group's major galaxies, mayindicate that it originated out of tidal debris.
| An IRAS High Resolution Image Restoration (HIRES) Atlas of All Interacting Galaxies in the IRAS Revised Bright Galaxy Sample
The importance of far-infrared observations for our understanding ofextreme activity in interacting and merging galaxies has beenillustrated by many studies. Even though two decades have passed sinceits launch, the most complete all-sky survey to date from which far-IRselected galaxy samples can be chosen is still that of the InfraredAstronomical Satellite (IRAS). However, the spatial resolution of theIRAS all-sky survey is insufficient to resolve the emission fromindividual galaxies in most interacting galaxy pairs, and hence previousstudies of their far-IR properties have had to concentrate either onglobal system properties or on the properties of very widely separatedand weakly interacting pairs. Using the HIRES image reconstructiontechnique, it is possible to achieve a spatial resolution ranging from30" to 1.5m (depending on wavelength and detector coverage), whichis a fourfold improvement over the normal resolution of IRAS. This issufficient to resolve the far-IR emission from the individual galaxiesin many interacting systems detected by IRAS, which is very importantfor meaningful comparisons with single, isolated galaxies. We presenthigh-resolution 12, 25, 60, and 100 μm images of 106 interactinggalaxy systems contained in the IRAS Revised Bright Galaxy Sample (RBGS,Sanders et al.), a complete sample of all galaxies having a 60 μmflux density greater than 5.24 Jy. These systems were selected to haveat least two distinguishable galaxies separated by less than threeaverage galactic diameters, and thus we have excluded very widelyseparated systems and very advanced mergers. Additionally, some systemshave been included that are more than three galactic diameters apart,yet have separations less than 4' and are thus likely to suffer fromconfusion in the RBGS. The new complete survey has the same propertiesas the prototype survey of Surace et al. We find no increased tendencyfor infrared-bright galaxies to be associated with other infrared-brightgalaxies among the widely separated pairs studied here. We find smallenhancements in far-IR activity in multiple galaxy systems relative toRBGS noninteracting galaxies with the same blue luminosity distribution.We also find no differences in infrared activity (as measured byinfrared color and luminosity) between late- and early-type spiralgalaxies.
| The PDS versus Markarian starburst galaxies: comparing strong and weak IRAS emitter at 12 and 25 μm in the nearby Universe
The characteristics of the starburst galaxies from the Pico dos Diassurvey (PDS) are compared with those of the nearby ultraviolet (UV)bright Markarian starburst galaxies, having the same limit in redshift(vh < 7500 km s-1) and absolute B magnitude(MB < -18). An important difference is found: theMarkarian galaxies are generally undetected at 12 and 25 μm in IRAS.This is consistent with the UV excess shown by these galaxies andsuggests that the youngest star-forming regions dominating thesegalaxies are relatively free of dust.The far-infrared selection criteria for the PDS are shown to introduce astrong bias towards massive (luminous) and large size late-type spiralgalaxies. This is contrary to the Markarian galaxies, which are found tobe remarkably rich in smaller size early-type galaxies. These resultssuggest that only late-type spirals with a large and massive disc arestrong emitters at 12 and 25 μm in IRAS in the nearby Universe.The Markarian and PDS starburst galaxies are shown to share the sameenvironment. This rules out an explanation of the differences observedin terms of external parameters. These differences may be explained byassuming two different levels of evolution, the Markarian being lessevolved than the PDS galaxies. This interpretation is fully consistentwith the disc formation hypothesis proposed by Coziol et al. to explainthe special properties of the Markarian SBNG.
| The IRAS Revised Bright Galaxy Sample
IRAS flux densities, redshifts, and infrared luminosities are reportedfor all sources identified in the IRAS Revised Bright Galaxy Sample(RBGS), a complete flux-limited survey of all extragalactic objects withtotal 60 μm flux density greater than 5.24 Jy, covering the entiresky surveyed by IRAS at Galactic latitudes |b|>5°. The RBGS includes629 objects, with median and mean sample redshifts of 0.0082 and 0.0126,respectively, and a maximum redshift of 0.0876. The RBGS supersedes theprevious two-part IRAS Bright Galaxy Samples(BGS1+BGS2), which were compiled before the final(Pass 3) calibration of the IRAS Level 1 Archive in 1990 May. The RBGSalso makes use of more accurate and consistent automated methods tomeasure the flux of objects with extended emission. The RBGS contains 39objects that were not present in the BGS1+BGS2,and 28 objects from the BGS1+BGS2 have beendropped from RBGS because their revised 60 μm flux densities are notgreater than 5.24 Jy. Comparison of revised flux measurements forsources in both surveys shows that most flux differences are in therange ~5%-25%, although some faint sources at 12 and 25 μm differ byas much as a factor of 2. Basic properties of the RBGS sources aresummarized, including estimated total infrared luminosities, as well asupdates to cross identifications with sources from optical galaxycatalogs established using the NASA/IPAC Extragalactic Database. Inaddition, an atlas of images from the Digitized Sky Survey with overlaysof the IRAS position uncertainty ellipse and annotated scale bars isprovided for ease in visualizing the optical morphology in context withthe angular and metric size of each object. The revised bolometricinfrared luminosity function, φ(Lir), forinfrared-bright galaxies in the local universe remains best fit by adouble power law, φ(L)~Lα, withα=-0.6(+/-0.1) and α=-2.2(+/-0.1) below and above the``characteristic'' infrared luminosityL*ir~1010.5Lsolar,respectively. A companion paper provides IRAS High Resolution (HIRES)processing of over 100 RBGS sources where improved spatial resolutionoften provides better IRAS source positions or allows for deconvolutionof close galaxy pairs.
| A catalog of warps in spiral and lenticular galaxies in the Southern hemisphere
A catalog of optical warps of galaxies is presented. This can beconsidered complementary to that reported by Sánchez-Saavedra etal. (\cite{sanchez-saavedra}), with 42 galaxies in the northernhemisphere, and to that by Reshetnikov & Combes(\cite{reshetnikov99}), with 60 optical warps. The limits of the presentcatalog are: logr 25 > 0.60, B_t< 14.5, delta (2000) <0deg, -2.5 < t < 7. Therefore, lenticular galaxies havealso been considered. This catalog lists 150 warped galaxies out of asample of 276 edge-on galaxies and covers the whole southern hemisphere,except the Avoidance Zone. It is therefore very suitable for statisticalstudies of warps. It also provides a source guide for detailedparticular observations. We confirm the large frequency of warpedspirals: nearly all galaxies are warped. The frequency and warp angle donot present important differences for the different types of spirals.However, no lenticular warped galaxy has been found within the specifiedlimits. This finding constitutes an important restriction fortheoretical models.
| ISOCAM Observations of a Galaxy Merging Sequence
We present mid-IR (5-16μm) images and spectra of a sequence ofinteracting galaxies, observed by ISOCAM. The galaxies were selected asbeing at progressive stages in the time evolution of a merging event andhaving no detected contribution from an active galactic nucleus (AGN) intheir mid-IR spectrum. To trace the intensity of the global starformation in those galaxies, we use the ratio of the 15μm to 7μmflux. Our analysis indicates that this ratio increases from ~ 1 to ~ 5as galaxies move from the pre-starburst to the merging/starburst phaseonly to decrease to ~ 1 again in the post-starburst phase of the evolvedmerger remnants. Moreover, we find that the variation of this ratio iswell correlated with the one of the IRAS 25μm/12μm and60μm/100μm flux ratios. Improving upon these results using theInfrared Spectrograph (IRS) on board the Space Infrared TelescopeFacility (SIRTF) is briefly discussed.
| A New Mid-Infrared Diagnostic between AGN and Starbursts
We present a new set of diagnostics which allow us to trace and classifyin a statistical manner the mid-IR emission produced by active galacticnuclei (AGN) and star-forming regions. We construct a diagram based onthe strength of the unidentified infrared band (UIB) at 6.2 μm, andthe intensity of the continuum at short (6 μm) and long wavelengths(15 μm). We interpret the integrated mid-IR emission in late-typegalaxies as resulting from three individual contributions coming fromHII regions, diffuse/photodissociation regions (PDRs), and AGN. Based onthis assumption, our diagnostic diagram provides a quantitative estimateof the AGN and starburst contribution to an observed mid-IR spectrum. Weshow that UIB emission is very faint or absent in regions harbouringintense and hard radiation fields as in the case of AGN or `pure' HIIstarburst regions where UIB carriers can be destroyed byphotodissociation. However, contrary to starburst spectra, typical AGNspectra present a strong hot continuum below 9 μm originating fromhot dust heated by the AGN radiation field. An extrapolation of thisdiagnostic towards other mid-IR observations should improve ourknowledge of the AGN/starburst connection.
| Luminous Infrared Galaxies. III. Multiple Merger, Extended Massive Star Formation, Galactic Wind, and Nuclear Inflow in NGC 3256
We report detailed evidence for multiple merger, extended massive starformation, galactic wind, and circular/noncircular motions in theluminous infrared galaxy NGC 3256, based on observations ofhigh-resolution imaging (Hubble Space Telescope, ESO NTT), and extensivespectroscopic data (more than 1000 spectra, collected at EstaciónAstrofísica de Bosque Alegre, Complejo Astronómico elLeoncito, Cerro Tololo InterAmerican Observatory, and IUEobservatories). We find in a detailed morphological study (resolution~15 pc) that the extended massive star formation process detectedpreviously in NGC 3256 shows extended triple asymmetrical spiral arms(r~5 kpc), emanating from three different nuclei. The main opticalnucleus shows a small spiral disk (r~500 pc), which is a continuation ofthe external one and reaches the very nucleus. The core shows blueelongated structure (50 pc×25 pc) and harbors a blue stellarcluster candidate (r~8 pc). We discuss this complex morphology in theframework of an extended massive star formation driven by a multiplemerger process (models of Hernquist et al. and Taniguchi et al.). Westudy the kinematics of this system and present a detailed Hαvelocity field for the central region(40''×40'' rmax~30''~5kpc), with a spatial resolution of 1" and errors of +/-15 kms-1. The color and isovelocity maps show mainly (1) akinematic center of circular motion with ``spider'' shape, locatedbetween the main optical nucleus and the close (5") mid-IR nucleus and(2) noncircular motions in the external parts. We obtained three``sinusoidal rotation curves'' (from the Hα velocity field) aroundposition angle (P.A.) ~55°, ~90°, and ~130°. In the mainoptical nucleus we found a clear ``outflow component'' associated withgalactic winds plus an ``inflow radial motion.'' The outflow componentwas also detected in the central and external regions (r<=5-6 kpc).The main axis of the inflow region (P.A.~80deg) ispractically perpendicular to the ouflow axis (atP.A.~160deg). We analyze in detail the physical conditions inthe giant H II regions located in the asymmetric spiral arms, the twomain optical nuclei, and the outflow component (using long-slitspectroscopy, plus standard models of photoionization, shocks, andstarbursts). We present four detailed emission-line ratios (NII/Hα, S II/Hα, S II/S II), and FWHM (Hα) maps for thecentral region (30''×30''rmax~22''~4 kpc), with a spatial resolution of 1".In the central region (r~5-6 kpc) we detected that the nuclear starburstand the extended giant H II regions (in the spiral arms) have verysimilar properties, i.e., high metallicity and low-ionization spectra,with Teff=35,000 K, solar abundance, a range ofTe~6000-7000 K, and Ne~100-1000 cm-3.The nuclear and extended outflow shows properties typical of galacticwind/shocks, associated with the nuclear starburst. We suggest that theinteraction between dynamical effects, the galactic wind (outflow),low-energy cosmic rays, and the molecular+ionized gas (probably in theinflow phase) could be the possible mechanism that generate the``similar extended properties in the massive star formation, at a scaleof 5-6 kpc!'' We have also studied the presence of the closemerger/interacting systems NGC 3256C (at ~150 kpc, ΔV=-100 kms-1) and the possible association between the NGC 3256 and3263 groups of galaxies. In conclusion, these results suggest that NGC3256 is the product of a multiple merger, which generated an extendedmassive star formation process with an associated galactic wind plus anuclear inflow. Therefore, NGC 3256 is another example in which therelation between mergers and extreme starburst (and the powerfulgalactic wind, ``multiple'' Type II supernova explosions) play animportant role in the evolution of galaxies (the hypothesis of Rieke etal., Joseph et al., Terlevich et al., Heckman et al., and Lípariet al.). Based on observations obtained at the Hubble Space Telescope(HST; Wide Field Planetary Camera 2 [WFPC2] and NICMOS) satellite;International Ultraviolet Explorer (IUE) satellite; European SouthernObservatory (ESO, NTT); Chile, Cerro Tololo Inter-American Observatory(CTIO), Chile; Complejo Astronómico el Leoncito (CASLEO),Argentina; Estación Astrofísica de Bosque Alegre(BALEGRE), Argentina.
| 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
| Mid-infrared diagnostics to distinguish AGNs from starbursts
We present new mid-infrared (MIR) diagnostics to distinguish emission ofactive galactic nuclei (AGN) from that originating in starburst regions.Our method uses empirical spectroscopic criteria based on the fact thatMIR emission from star forming or active galaxies arises mostly from HIIregions, photo-dissociation regions (PDRs) and AGNs. The analysis of thestrength of the 6.2 mu m Unidentified Infrared Band (UIB) and the MIRcontinuum shows that UIBs are very faint or absent in regions harboringthe intense and hard radiation fields of AGNs and pure HII regions,where the UIB carriers could be destroyed. The MIR signature of AGNs isthe presence of an important continuum in the 3-10 mu m band whichoriginates from very hot dust heated by the intense AGN radiation field.Using these two distinct spectral properties found in our MIR templates,we build diagnostic diagrams which provide quantitative estimates of theAGN, PDR and HII region contribution in a given MIR spectrum. This newMIR classification can be used to reveal the presence of AGNs highlyobscured by large columns of dust. Based on observations made with ISO,an ESA project with instruments funded by ESA Member States (especiallythe PI countries: France, Germany, the Netherlands and the UnitedKingdom) and with the participation of ISAS and NASA.
| The Pico DOS Dias Survey Starburst Galaxies
We discuss the nature of the galaxies found in the Pico dos Dias Survey(PDS) for young stellar objects. The PDS galaxies were selected from theIRAS Point Source catalog. They have flux density of moderate or highquality at 12, 25, and 60 μm and spectral indices in the ranges -3.00<= alpha(25, 12) <= + 0.35 and -2.50 <= alpha(60, 25) <=+0.85. These criteria allowed the detection of 382 galaxies, which are amixture of starburst and Seyfert galaxies. Most of the PDS Seyfertgalaxies are included in the catalog of warm IRAS sources by de Grijp etal. The remaining galaxies constitute a homogeneous sample of luminous[log F (L_B/L_ȯ) = 9.9 +/- 0.4] starburst galaxies, 67% of whichwere not recognized as such before. The starburst nature of the PDSgalaxies is established by comparing their L_IR/L_B ratios and IRAScolors with a sample of emission-line galaxies from the literaturealready classified as starburst galaxies. The starburst galaxies show anexcess of FIR luminosity, and their IRAS colors are significantlydifferent from those of Seyfert galaxies-99% of the starburst galaxiesin our sample have a spectral index alpha(60, 25) < -1.9. As opposedto Seyfert galaxies, very few PDS starbursts are detected in X-rays. Inthe infrared, the starburst galaxies form a continuous sequence withnormal galaxies. But they generally can be distinguished from normalgalaxies by their spectral index alpha(60, 25) > -2.5. This colorcutoff also marks a change in the dominant morphologies of the galaxies:the normal IRAS galaxies are preferentially late-type spirals (Sb andlater), while the starbursts are more numerous among early-type spirals(earlier than Sbc). This preference of starbursts for early-type spiralsis not new, but a trait of the massive starburst nucleus galaxies(Coziol et al.). As in other starburst nucleus galaxy samples, the PDSstarbursts show no preference for barred galaxies. No difference isfound between the starbursts detected in the FIR and those detected onthe basis of UV excess. The PDS starburst galaxies represent the FIRluminous branch of the UV-bright starburst nucleus galaxies, with meanFIR luminosity log (L_IR/L_ȯ) = 10.3 +/- 0.5 and redshifts smallerthan 0.1. They form a complete sample limited in flux in the FIR at 2 x10^-10 ergs cm^-2 s^-1.
| 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.
| Redshift Distribution of Galaxies in the Southern Milky Way Region 210 degrees < L < 360 degrees and B < 15 degrees
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJS..107..521V&db_key=AST
| A 1.425 GHz Atlas of the IRAS Bright Galaxy Sample, Part II
Galaxies with δ >= -45^deg^ and |b| >= 10^deg^ in the IRASBright Galaxy Sample, Part II, were observed at 1.425 GHz by the VeryLarge Array in its B, CnB, C, DnC, and D configurations. An atlas ofradio contour maps and a table listing the principal radio sourceparameters (position, flux density, angular size) are given. This atlasof 187 galaxies supplements the 1.49 GHz atlas of 313 galaxies in therevised Bright Galaxy Sample, Part I. Together, they are complete forextragalactic sources stronger than S = 5.24Jy at λ = 60 micronsin the area |b| > 10^deg^, δ > -45^deg^. To the extent thatthe far-infrared and radio brightness distributions overlap, these radiomaps provide the most accurate positions and high-resolution images ofthe brightest extragalactic far-infrared sources.
| The IRAS Bright Galaxy Survey - Part II: Extension to Southern Declinations (delta ~< -30), and Low Galactic Latitudes (f<|b|
Complete IRAS Observations and redshifts are reported for all sourcesidentified in the IRAS Bright Galaxy Survey-Part II (hereafter referredto as BGS_2_). Source positions, radial velocities, optical magnitudes,and total flux densities, peak flux densities, and spatial extents at12, 25, and 100 ,microns are reported for 288 sources having 60 micronflux densities > 5.24 Jy, the completeness limit of the originalBright Galaxy Survey [Soifer et al., AJ, 98,766(1989)], hereafterreferred to as BGS_1_. These new data represent the extension of theIRAS Bright Galaxy Survey to southern declinations,δ<~-30^deg^, and low Galactic latitudes,5^deg^<|b|<30^deg^. Although the sky coverage of the BGS_2_ (~19935 deg^2^) is 37% larger than the sky coverage of the BGS_1_, thenumber of sources is 8% smaller due primarily to large scale structurein the local distribution of galaxies. Otherwise, the sources in theBGS_2_ show similar relationships between number counts and flux densityas observed for the 313 sources in the BGS_1_. The BGS_2_ along with theearlier BGS, represents the best sample currently available for definingthe infrared properties of galaxies in the local (z <~ 0.1) Universe.
| Spectroscopic Observations of ARP / Madore Interacting Galaxies - Part Two - Galaxies with Tails Loops of Material or Debris
We present spectroscopic observations of 103 galaxies from a sample ofinteracting galaxies with tails, loops of material or debris. Radialvelocities, relative emission-line intensity measurements and opticalclassifications are presented. Three new Seyfert candidates areidentified. The frequency of Seyfert-type nuclei in our sample of`strongly' interacting galaxies (3.9 per cent; 4/103) is notsignificantly different from that of the interacting doubles ofcomparably sized galaxies (3.1 per cent; 4/129), which are presumably atan earlier stage of interaction than the galaxies observed in thepresent-study. However, the lack of a suitable control sample for ourinteracting samples prevents us from confirming whether interactions andmergers enhance Seyfert nuclear activity compared to that of non-interacting galaxies. A large fraction of the galaxies in our sampleshow strong H II region type emission lines, which indicate ongoingenhanced star formation activity. Since the systems are at a relativelyearly stage of the merger process and are near the peak of theirstarburst activities, the interstellar gas in the disc must be collectedin the nuclear region on time-scales less than about a few X 10^8^-10^9^yr. Strong H II region type emission lines superimposed on a strongstellar Balmer absorption spectrum are seen in many of the systems inour sample, suggesting a possible recurrent starburst or propagation ofstar-forming regions within the galaxy. High-resolution imaging studiesare required for further analysis of the sample.
| A search for IRAS galaxies behind the southern Milky Way
We systematically searched for IRAS galaxies with 60 micrometer fluxdensity larger than 0.6 Jy by using the UK Schmidt Infrared and IIIa-JAtlases in the Milky Way region (absolute value of b less than 15 deg)between l = 210 deg and 360 deg. We first selected about 4000 IRAS pointsources by using our far-infrared criteria, which are optimized for thesearch of IRAS galaxies behind the Milky Way region, and then inspectedvisually the optical counterparts of them on the Schmidt Atlas filmcopies. We found 966 IRAS sources associated with galaxy-like objects.The list of the objects is presented here with the IRAS source name,Galactic coordinates, IRAS flux densities, field number and emulsion ofthe Atlas, type and size of galaxy (-like) image, redshift,multiplicity, and cross-identification. Of these, 423 galaxies arealready cataloged in the Catalog of Galaxies and Quasars Observed in theIRAS Survey, and most of the remaining 543 galaxy candidates are newlyidentified in this search. Although the radial velocities are known foronly 387 galaxies, of which 60 were newly measured by us so far, weinferred the contamination by Galactic objects to be small from the goodcorrelation between the sky distributions of the newly identified galaxycandidates and the previously cataloged galaxies. In the regions wherethe Galactic molecular clouds dominate, almost all the sources were notidentified as galaxies. The detected galaxies are clustered in the threeregions around l = 240 deg, 280 deg, and 315 deg, where the projectednumber densities are higher than the whole-sky average of IRAS galaxiesof the same flux limit.
| 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.
| Groups of galaxies within 80 Mpc. II - The catalogue of groups and group members
This paper gives a catalog of the groups and associations obtained bymeans of a revised hierarchical algorithm applied to a sample of 4143galaxies with diameters larger than 100 arcsec and redshifts smallerthan 6000 km/s. The 264 groups of galaxies obtained in this way (andwhich contain at least three sample galaxies) are listed, with the looseassociations surrounding them and the individual members of eachaggregate as well; moreover, the location of every entity among 13regions corresponding roughly to superclusters is specified. Finally,1729 galaxies belong to the groups, and 466 to the associations, i.e.,the total fraction of galaxies within the various aggregates amounts to53 percent.
| Groups of galaxies within 80 Mpc. I - Grouping hierarchical method and statistical properties
An all-sky sample of 4143 galaxies comprising all the objects with anapparent diameter D(25) larger than 100 arcsec and with recessionvelocities smaller than 6000 km/s (i.e., closer than 80 Mpc) wasanalyzed using a hierarchical algorithm similar to Tully's (1987)algorithm, in order to classify the galaxies into groups defined asentities having an average luminosity density higher than 8 x 10 exp 9solar luminosity in the B band/Mpc cubed. The hierarchy is built on themass density of the aggregates progressively formed by the method,corrected for the loss of faint galaxies with the distance. In this way,264 groups of at least three members were identified, among which 82have more than five members and are located at distances lower than 40Mpc. It was found that (1) almost all the crossing times are lower thanH0 exp -1, confirming the bound nature of the groups; (2) themedian virial mass to blue luminosity ratio of the groups is 74 solarmass per solar luminosity in the B band; and (3) the M/L ratio increaseswith the group size, indicating the presence of dark matter aroundgalaxies to a distance of 500 kpc.
| The QMW IRAS galaxy catalogue - A highly complete and reliable IRAS 60-micron galaxy catalogue
This study presents a highly complete and reliable IRAS 60-micron galaxycatalog covering 82 percent of the sky. IRAS color conditions are usedto exclude galactic sources, including the remaining cirrus sources. Allsources flagged as extended, confused, or having a poor correlationcoefficient with a point-source template are examined with the raw IRASdata and accurate fluxes determined using mapping routines. Thecompleteness, reliability, and flux accuracy of the catalog arediscussed. Identifications are made with existing optical galaxycatalogs and with galaxy redshift surveys in the literature. It isestimated that redshifts are available for 79 percent of the galaxies inthe catalog with V less than 5000 km/s, and the 3D distribution of suchgalaxies is displayed. The dipole component of the surface-brightnessdistribution of galaxies in the catalog is discussed.
| Southern Galaxy Catalogue.
Not Available
| Faint southern galaxies with H-alpha emission
A catalog of 113 emission line galaxies, selected by the presence ofH-alpha + N II forbidden line emission, is presented. The objects wereselected from an objective prism survey made with the ESO Schmidttelescope, using the (IIIaF + RG630) plate-filter combination.
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