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FLASH redshift survey - I. Observations and catalogue
The FLAIR Shapley-Hydra (FLASH) redshift survey catalogue consists of4613 galaxies brighter than bJ= 16.7 (corrected for Galacticextinction) over a 700-deg2 region of sky in the generaldirection of the Local Group motion. The survey region is a70°× 10° strip spanning the sky from the ShapleySupercluster to the Hydra cluster, and contains 3141 galaxies withmeasured redshifts. Designed to explore the effect of the galaxyconcentrations in this direction (in particular the Supergalactic planeand the Shapley Supercluster) upon the Local Group motion, the 68 percent completeness allows us to sample the large-scale structure betterthan similar sparsely-sampled surveys. The survey region does notoverlap with the areas covered by ongoing wide-angle (Sloan or 2dF)complete redshift surveys. In this paper, the first in a series, wedescribe the observation and data reduction procedures, the analysis forthe redshift errors and survey completeness, and present the surveydata.
| Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
In this paper we describe the Nearby Optical Galaxy (NOG) sample, whichis a complete, distance-limited (cz<=6000 km s-1) andmagnitude-limited (B<=14) sample of ~7000 optical galaxies. Thesample covers 2/3 (8.27 sr) of the sky (|b|>20deg) andappears to have a good completeness in redshift (97%). We select thesample on the basis of homogenized corrected total blue magnitudes inorder to minimize systematic effects in galaxy sampling. We identify thegroups in this sample by means of both the hierarchical and thepercolation ``friends-of-friends'' methods. The resulting catalogs ofloose groups appear to be similar and are among the largest catalogs ofgroups currently available. Most of the NOG galaxies (~60%) are found tobe members of galaxy pairs (~580 pairs for a total of ~15% of objects)or groups with at least three members (~500 groups for a total of ~45%of objects). About 40% of galaxies are left ungrouped (field galaxies).We illustrate the main features of the NOG galaxy distribution. Comparedto previous optical and IRAS galaxy samples, the NOG provides a densersampling of the galaxy distribution in the nearby universe. Given itslarge sky coverage, the identification of groups, and its high-densitysampling, the NOG is suited to the analysis of the galaxy density fieldof the nearby universe, especially on small scales.
| The Shapley Supercluster. I. Spectroscopic Observations in the Central Region
We present a new analysis of the kinematics of the Shapley superclusterbased on radial velocities for 1087 galaxies in the clusters A3558(Shapley 8), A3528 (Klemola 21), A3532 (Klemola 22), A3530, A3556 (SC1321-314), A3559 (CE 1327-292), A3560, A3562, SC 1329-314 and in theintercluster region of the core of the supercluster, of which 367 arenew measurements. We also present accurate positions from APM and MAMAscans of the ESO/SERC Southern Sky Survey photographic plates. We obtainnew velocity dispersions and estimate the masses of the member clusters,evaluating dynamical models of the supercluster. The supercluster isfound to be significantly flattened. We find that for {OMEGA}_0_ = 0.3,H_0_= 75 km s^-1^ Mpc^-1^, the gravitational pull of the superclustermay account for up to 25% of the peculiar velocity of the Local Grouprequired to explain the dipole anisotropy of the Cosmic MicrowaveBackground radiation, in which case the mass of the supercluster wouldbe dominated by intercluster dark matter. This fractional contributionwould be considerably higher for combinations of significantly lowervalues of {OMEGA}_0_ and higher values of H_0_.
| 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.
| 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 velocity field of clusters of galaxies within 100 megaparsecs. I - Southern clusters
Distances from the Tully-Fisher relation have been measured with theParkes radio telescope for eight additional southern clusters ofgalaxies in the redshift range 2500-5000 km/s. Most of them have large(average 1000 km/s) positive peculiar velocities in a comoving frame inwhich the microwave background radiation shows no dipole anisotropy. Infive out of eight cases these measurements have a significance at orabove the 2-sigma level. Outflow is seen on both sides of the Galacticplane. The source of this large-scale flow, if gravitational in orgin,lies at or beyond the limit of the present sample.
| Redshifts for galaxies in southern clusters
Redshifts for galaxies, including the clusters ZW 9-19 and Klemola 27,in the ESO/SRC survey field 444 are presented based on observationscarried out in May 1980 and April 1981 with the 1.52-m ESO telescope inLa Silla. Satisfactory agreement is found with previous data. Thesurveyed sky area contains the Hydra/Centaurus supercluster with meanradial velocities between 3000 and 5000 km/s, behind which seems to be alarge empty space extending out to a redshift of about 9000 km s.
| A search for QSOs in the fields of nearby galaxies. I - NGC 253, NGC 5236 and NGC 6744
Positions and magnitudes of QSO and background-galaxy candidatesidentified on UKST prism plates centered on the galaxies NGC 253, NGC5236, and NGC 6744 are given. Finding charts are given for four of thecandidates which have been confirmed as QSOs by follow-up low-resolutionspectroscopy. A further seven candidates are galaxies sufficientlybright in the region of the Ca II 3933, 3968 A lines to permit futurehigh-resolution spectroscopy.
| Redshifts in Klemola 27
Observational data for galaxies in the galaxy cluster Klemola 27gathered over the last few years are presented. These are mostly newredshifts and further, accurate coordinates and morphological types fora large number of 'prominent' galaxies in the ESO/SRC-Survey fields 444and 445. A few preliminary H I radial velocities are also reported. Thedata available for this cluster are briefly discussed.
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