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Structures in the Great Attractor region
To further our understanding of the Great Attractor (GA), we haveundertaken a redshift survey using the 2-degree Field (2dF) instrumenton the Anglo-Australian Telescope (AAT). Clusters and filaments in theGA region were targeted with 25 separate pointings resulting inapproximately 2600 new redshifts. Targets included poorly studied X-rayclusters from the Clusters in the Zone of Avoidance (CIZA) Catalogue aswell as the Cen-Crux and PKS 1343-601 clusters, both of which lie closeto the classic GA centre. For nine clusters in the region, we reportvelocity distributions as well as virial and projected mass estimates.The virial mass of CIZA J1324.7-5736, now identified as a separatestructure from the Cen-Crux cluster, is found to be ~3 ×1014Msolar, in good agreement with the X-rayinferred mass. In the PKS 1343-601 field, five redshifts are measured ofwhich four are new. An analysis of redshifts from this survey, incombination with those from the literature, reveals the dominantstructure in the GA region to be a large filament, which appears toextend from Abell S0639 (l = 281°, b = +11°) to (l ~ 5°, b ~-50°), encompassing the Cen-Crux, CIZA J1324.7-5736, Norma and PavoII clusters. Behind the Norma cluster at cz ~ 15000kms-1, themasses of four rich clusters are calculated. These clusters (TriangulumAustralis, Ara, CIZA J1514.6-4558 and CIZA J1410.4-4246) may contributeto a continued large-scale flow beyond the GA. The results of theseobservations will be incorporated into a subsequent analysis of the GAflow.
| The 1000 Brightest HIPASS Galaxies: H I Properties
We present the HIPASS Bright Galaxy Catalog (BGC), which contains the1000 H I brightest galaxies in the southern sky as obtained from the H IParkes All-Sky Survey (HIPASS). The selection of the brightest sourcesis based on their H I peak flux density (Speak>~116 mJy)as measured from the spatially integrated HIPASS spectrum. The derived HI masses range from ~107 to 4×1010Msolar. While the BGC (z<0.03) is complete inSpeak, only a subset of ~500 sources can be consideredcomplete in integrated H I flux density (FHI>~25 Jy kms-1). The HIPASS BGC contains a total of 158 new redshifts.These belong to 91 new sources for which no optical or infraredcounterparts have previously been cataloged, an additional 51 galaxiesfor which no redshifts were previously known, and 16 galaxies for whichthe cataloged optical velocities disagree. Of the 91 newly cataloged BGCsources, only four are definite H I clouds: while three are likelyMagellanic debris with velocities around 400 km s-1, one is atidal cloud associated with the NGC 2442 galaxy group. The remaining 87new BGC sources, the majority of which lie in the zone of avoidance,appear to be galaxies. We identified optical counterparts to all but oneof the 30 new galaxies at Galactic latitudes |b|>10deg.Therefore, the BGC yields no evidence for a population of``free-floating'' intergalactic H I clouds without associated opticalcounterparts. HIPASS provides a clear view of the local large-scalestructure. The dominant features in the sky distribution of the BGC arethe Supergalactic Plane and the Local Void. In addition, one can clearlysee the Centaurus Wall, which connects via the Hydra and Antlia Clustersto the Puppis Filament. Some previously hardly noticable galaxy groupsstand out quite distinctly in the H I sky distribution. Several newstructures, including some not behind the Milky Way, are seen for thefirst time.
| A catalogue of galaxies behind the southern Milky Way. II. The Crux and Great Attractor regions (l~ 289o to 338o)
In this second paper of the catalogue series of galaxies behind thesouthern Milky Way, we report on the deep optical galaxy search in theCrux region (289o <= l <= 318o and-10o <= b <= 10o) and the Great Attractorregion (316o <= l <= 338o and-10o <= b <= 10o}). The galaxy cataloguesare presented, a brief description of the galaxy search given, as wellas a discussion on the distribution and characteristics of the uncoveredgalaxies. A total of 8182 galaxies with major diameters D >~ 0.2arcmin were identified in this ~ 850 square degree area: 3759 galaxiesin the Crux region and 4423 galaxies in the Great Attractor region. Ofthe 8182 galaxies, 229 (2.8%) were catalogued before in the optical (3in radio) and 251 galaxies have a reliable (159), or likely (92)cross-identification in the IRAS Point Source Catalogue (3.1%). A numberof prominent overdensities and filaments of galaxies are identified.They are not correlated with the Galactic foreground extinction andhence indicative of extragalactic large-scale structures. Redshiftsobtained at the South African Astronomical Observatory (SAAO) for 518 ofthe newly catalogued galaxies in the Crux and Great Attractor regions(Fairall et al. \cite{Fairall98}; Woudt et al. \cite{Woudt99}) confirmdistinct voids and clusters in the area here surveyed. With this opticalgalaxy search, we have reduced the width of the optical ``Zone ofAvoidance'' for galaxies with extinction-corrected diameters larger than1.3 arcmin from extinction levels AB >= 1.0m toAB >= 3.0m: the remaining optical Zone of Avoidance is nowlimited by | b | <~ 3o (see Fig. \ref{cruxf1new}). The twooptical catalogues and their respective listings of IRAScross-identifications are available in electronic format 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/380/441
| Galaxy coordinates. II. Accurate equatorial coordinates for 17298 galaxies
Using images of the Digitized Sky Survey we measured coodinates for17298 galaxies having poorly defined coordinates. As a control, wemeasured with the same method 1522 galaxies having accurate coordinates.The comparison with our own measurements shows that the accuracy of themethod is about 6 arcsec on each axis (RA and DEC).
| Extragalactic large-scale structures behind the Southern Milky Way. II. Redshifts obtained at the SAAO in the Crux region
In our systematic optical galaxy search behind the southern Milky Way,3760 (mostly unknown) galaxies with diameters D > 0.2' wereidentified in the Crux region (287° < l < 318°, |b| <10°, cite [Woudt & Kraan-Korteweg 1997]{wo97}). Prior to thisinvestigation, only 65 of these galaxies had known redshifts. In orderto map the galaxy distribution in redshift space we obtained spectra for226 bright (BJ < 18\mag0) objects with the 1.9 m telescopeof the South African Astronomical Observatory (SAAO). Redshifts could bedetermined for 209 objects, of which 173 have good signal-to-noiseratios. Of the 36 tentative redshifts, four are confirmed throughindependent values in the literature. The redshifts of three objectsindicate them to be galactic in origin. One of these confirms asuspected Planetary Nebula. For 17 of the galaxies, no redshift could bedetermined due to poor signal-to-noise ratios. In addition, 26 redshiftshave have been measured in the Hydra-Antlia region investigated earlier(cite [Kraan-Korteweg et al. 1995]{kr95}), of which one is a tentativeestimate. Two main structures crossing the Galactic Plane in the Cruxregion have now become clear. A narrow, nearby filament from (\ell, b) =(340°, -25°) to the Centaurus cluster can be traced. Thisfilament runs almost parallel to the extension of the Hydra-Antliaclusters found earlier and is part of what we have earlier termed the``Centaurus Wall'' extending in redshift-space between 0 <= v <=6000 {km\ s(-1) } (\cite[Fairall & Paverd 1995]{fa95}). The mainoutcome of this survey however, is the recognition of another massiveextended structure between 4000 <= v <= 8000 {{km\ s(-1) }}. Thisbroad structure, dubbed the Norma Supercluster (\cite[Woudt et al.1997]{wou97}), runs nearly parallel to the Galactic Plane from Vela toACO 3627 (its centre) from where it continues to the Pavo cluster. Thismassive structure is believed to be associated with the Great Attractor.The survey has furthermore revealed a set of cellular structures,similar to those seen in redshift space at higher galactic latitudes,but never before seen so clearly behind the Milky Way. All the tablesare only available in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Unveiling a connection between large-scale structures behind the southern Milky Way
A redshift survey of galaxies located in the direction of the southernMilky Way has been carried out using the FLAIR multi-objects system onthe 1.2-m UK Schmidt Telescope (UKST) at the Anglo-AustralianObservatory in Australia. The galaxy sample was extracted from the LEDAand COSMOS data bases, but essentially by scanning by eye four plates ofthe UKST/SERC Survey in the region between the Centaurus complex and thePavo-Indus (PI) wall. The galaxies selected have high central surfacebrightnesses and are distributed evenly over the whole search area. Themajority of the galaxies have apparent magnitudes in the range11.5
| 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
| The Catalog of Southern Ringed Galaxies
The Catalog of Southern Ringed Galaxies (CSRG) is a comprehensivecompilation of diameters, axis ratios, relative bar position angles, andmorphologies of inner and outer rings, pseudorings, and lenses in 3692galaxies south of declination -17 deg. The purpose of the catalog is toevaluate the idea that these ring phenomena are related to orbitalresonances with a bar or oval in galaxy potentials. The catalog is basedon visual inspection of most of the 606 fields of the Science ResearchCouncil (SRC) IIIa-J southern sky survey, with the ESO-B, ESO-R, andPalomar Sky surveys used as auxiliaries when needed for overexposed coreregions. The catalog is most complete for SRC fields 1-303 (mostly southof declination -42 deg). In addition to ringed galaxies, a list of 859mostly nonringed galaxies intended for comparison with other catalogs isprovided. Other findings from the CSRG that are not based on statisticsare the identification of intrinsic bar/ring misalignment; bars whichunderfill inner rings; dimpling of R'1pseudorings; pointy, rectangular, or hexagonal inner or outer ringshapes; a peculiar polar-ring-related system; and other extreme examplesof spiral structure and ring morphology.
| A volume-limited sample of IRAS galaxies to 4000 km/s, 3: CCD photometry from Palomar and Tololo observatories
An all-sky, quasi-volume-limited sample of 251 spiral galaxies within4000 km/s has been extracted from the redshift survey of InfraredAstronomy Satellite (IRAS) galaxies by Strauss (1992). Distance modulifor these objects estimated via the Tully-Fisher (TF) method allow thepeculiar velocity field and the cosmological density parameter to beconstrained within this volume. The TF relation we exploit relatesdeprojected neutral hydrogen line width to near-infrared luminosity.Herein we present I and V band photometry for 159 members of this sampleobtained with charge coupled device (CCD) cameras at Palomar and Tololoobservatories. Image processing and photometric calibration proceduresare described. Twenty seven objects with multiple calibratedobservations suggest that isophotal I band magnitudes are reproduced toequal to or less than 0.05 mag precision at sigmaI = 23.5 magarcsec-2, and that systematic run-to-run offsets are limitedto equal to or less than 0.05 I mag.
| A volume-limited sample of IRAS galaxies to 4000 km/s, 2: Neutral hydrogen observations from the Parkes telescope
We have extracted a volume-limited sample of spiral galaxies within 4000km/s from the Strauss et al. (1992) redshift survey of InfraredAstronomical Satellite (IRAS) galaxies. The purpose of the sample is touse distances obtained from the neutral hydrogen/near-infrared (I-band)Tully-Fisher relation to study deviations from uniform Hubble expansion.This will allow us to estimate the distribution of mass in the localuniverse and to place constraints on the value of the cosmologicaldensity parameter, omega 0. Here we report neutral hydrogen(H I) observations of 61 galaxies from this sample taken at the 64 mParkes telescope, 48 of which resulted in measured linewidth parameters.Empirical estimates of random and systematic errors in H I line widthsat low signal-to-noise ratio are described.
| 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.
| Photometry of luminous spiral galaxies in the direction of the Great Attractor
This paper presents photoelectric multiaperture BVI magnitudes for ahomogeneous sample of luminous spirals in the direction of the GreatAttractor. The total magnitudes B(T) and the mean colors (B - V) and (B- I) were determined for each galaxy and analyzed. The (B - I) colorchanges linearly with csc b over the range 3-10 and has a slope of 0.071mag. The A super bB values calculated from B - I agrees wellwith the A super bB values derived following the precepts ofBurstein and Heiles (1978). The (B - I) super b values show a slope of0.47 with log R. The corrected absolute magnitudes M superb,i,zB of spirals show little variation with luminosityclasses I, I-II, and II and have a dispersion of 0.85 mag. The samplewith well determined luminosities exhibits a uniform distribution overlog v up to v about 10,000 km/s. There is an indication that aselection-bias favoring higher luminosity galaxies sets in for spiralgalaxies with v greater than 10,000 km/s. The spirals with v less than10,000 km/s place a limit of about 500 km/s on peculiar velocities in ornear the Great Attractor.
| Redshifts of luminous spiral galaxies in the direction of the Great Attractor
The spatial distribution of a homogeneous samples of luminous spirals inthe direction of the 'Great Attractor' is studied. New radial velocitiesand published data yield redshifts for 94 percent of the sample. Thepresent survey, which does not include the cores of the Hydra andCentaurus clusters, shows no evidence for a major excess of velocitiesat or near the redshift of the Great Attractor. Luminous spirals withredshifts in the range 2000-4000 km/s are mainly distributed in a smallnumber of groups or clumps, whereas the spirals with redshifts in therange 4000-7000 km/s mostly appear to exhibit a rather smooth spatialdistribution.
| The supergalactic plane redshift survey
Redshift measurements, about 1000 of which are new, are presented for1314 galaxies in a survey toward the apex of the large-scale streamingflow for ellipticals. The velocity histogram shows that the excess ingalaxy number counts in this area is due to a substantial concentrationof galaxies with discrete peaks at V about 3000 km/s and V about 4500km/s. After correction for the sampling function, the centroid of thedensity distribution is found to be near V about 4500 km/s.Normalization to the more extensive SSRS survey, which was selected bythe same criteria, shows that the region studied contains a considerableoverdensity of galaxies from 2000 to 6000 km/s. This result is in goodagreement with the 'great attractor' model suggested by Lynden-Bell etal. (1988) which attributes the peculiar motions of elliptical galaxiesover a large region of space to an extensive mass overdensity whichincludes the Hydra-Centaurus and Pavo-Indus superclusters. The centroidof the density enhancement is also consistent with new data by Dresslerand Faber (1990) of peculiar motions of elliptical and spiral galaxies,both of which show a zero crossing of the Hubble line at approximately4500-5000 km/s.
| A survey of high-luminosity spirals in the direction of the great attractor
Luminosity-classification techniques have been used to study galaxies in33 SRC Schmidt fields centered on the position of 'The Great Attractor'.A catalog and finding charts are given for 191 spiral galaxies, whichare probably of DDO luminosity classes I, I-II, or II. Radial velocitiesof these objects should provide considerable insight into thethree-dimensional structure of this region of space. The surfacedistribution of galaxies in the survey area is seen to be stronglyaffected by Galactic absorption. It is therefore not clear if anysignificance should be attached to the observation that there is noobvious concentration of galaxies at, or near, the position of The GreatAttractor.
| Southern Galaxy Catalogue.
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