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21 CM H1 Line Spectra of Galaxies in Nearby Clusters
A compilation of HI line fluxes, systemic velocities and line widths ispresented for \Ndet detected galaxies, mostly in the vicinities of 30nearby rich clusters out to a redshift of z ~ .04, specifically for usein applications of the Tully-Fisher distance method. New 21 cm HI lineprofiles have been obtained for ~ 500 galaxies in 27 Abell clustersvisible from Arecibo. Upper limits are also presented for \Nnod galaxiesfor which HI emission was not detected. In order to provide ahomogeneous line width determination optimized for Tully-Fisher studies,these new data are supplemented by the reanalysis of previouslypublished spectra obtained both at Arecibo and Green Bank that areavailable in a digital archive. Corrections for instrumental broadening,smoothing, signal-to-noise and profile shape are applied, and anestimate of the error on the width is given. When corrected forturbulent broadening and viewing angle, the corrected velocity widthspresented here will provide the appropriate line width parameter neededto derive distances via the Tully-Fisher relation.
| Peculiar Velocities for Galaxies in the Great Wall.II.Analysis
We analyze the peculiar velocity field in the vicinity of the Great Wall(GW) using a sample of 172 spiral galaxies with reliable IRTF distanceestimates (Dell'Antonio et al. 1996). We examine three main issues: (1)the infall onto the GW, (2) large-scale flow, and (3) shear. We use aMonte Carlo method to remove selection-based biases from the peculiarvelocity sample. For the GW sample, the velocity bias is small (<150km s^-1^). We use the bias-corrected velocities to constrain the infalltowards the Great Wall. We thus have the first limits on the truespatial thickness of this structure. The data are best fit by an infallvelocity <= 150 km s^-1^. The 90% upper limit on the mean infallvelocity is ~500 km s^-1^. Consequently, the upper limit on thereal-space full width of the GW is d<11.2h^-1^ Mpc. Thus, the GreatWall is a thin, two- dimensional structure in real space as well as inredshift space. We calculate the best-fit estimate of the motion of theLocal Group with respect to the galaxy distribution: ν_flow_ ~725+/-400 km s^-1^ towards a 11.7 +/- 1.5 hr, δ =36.8deg^+/-55^deg^. Because our δ constraints are quiteweak, this flow is consistent with the CMB dipole (Smoot et al. 1992)and with the flow vector of Riess et al. (1995). The data are alsoconsistent at the 25% confidence level with the direction of large-scaleflow reported by Lauer & Postman (1994). We calculate theimprovement in sensitivity expected for a sample extending over the fulldeclination range of the GW. We also calculate the shear across theright ascension range of the GW. The GW region is quiet: the detectedthe shear across the range of the GW is -70+/-210 km s^-1^. The absenceof large shear constrains the amplitude of large-scale densityfluctuations (Feldman & Watkins 1995).
| 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.
| The Cancer Cluster - an unbound collection of groups
A surface density contour map of the Cancer Cluster derived from galaxycounts in the Zwicky catalog is presented. The contour map shows thatthe galaxy distribution is clumpy. When this spatial distribution iscombined with nearly complete velocity information, the clumps stand outmore clearly; there are significant differences in the mean velocitiesof the clumps which exceed their internal velocity dispersions. TheCancer Cluster is not a proper 'cluster' but is a collection of discretegroups, each with a velocity dispersion of approximately 300 km/s,separating from one another with the cosmological flow. Themass-to-light ratio for galaxies in the main concentration isapproximately 320 solar masses/solar luminosities (H0 = 100km/s Mpc).
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