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|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.
|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 HI Survey of the Bootes Void. II. The Analysis|
We discuss the results of a VLA [Napier et al., Proc. IEEE71,1295(1983)] H I survey of the Bootes void and compare thedistribution and H I properties of the void galaxies to those ofgalaxies found in a survey of regions of mean cosmic density. The Bootessurvey covers 1100 Mpc^3^ or ~ 1% of the volume of the void and consistsof 24 cubes of typically 2 Mpc x 2 Mpc x 1280 km s^-1^, centered onoptically known galaxies. Sixteen targets were detected in H I; 18previously uncataloged objects were discovered directly in H I. Thecontrol samples consists of 12 cubes centered on IRAS-selected galaxieswith FIR luminosities similar to those of the Bootes targets and locatedin regions of one to two times the cosmic mean density. In addition tothe 12 targets 29 companions were detected in H I. We find that thenumber of galaxies within 1 Mpc of the targets is the same to within afactor of 2 for void and control samples, and thus that the small scaleclustering of galaxies is the same in regions that differ by a factor of~6 in density on larger scales. A dynamical analysis of the galaxies inthe void suggests that on scales of a few Mpc the galaxies aregravitationally bound, forming interacting galaxy pairs, loose pairs,and loose groups. One group is compact enough to qualify as a Hicksoncompact group (hereafter referred to as HCG [Hickson, APJ, 255 , 382(1982)]. The galaxies found in the void are mostly late-type, gas-richsystems. A careful scrutiny of their H I and optical properties showsthem to be very similar to field galaxies of the same morphologicaltype. This, combined with our finding that the small scale clustering ofthe galaxies in the voids is the same as in the field, suggests that itis the near environment that mostly affects the evolution of galaxies.
|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 velocity-distance relation for galaxies on a bubble|
The characteristic diameter of the most prominent void in the redshiftsurvey of de Lapparent et al. (1986) is measured. Distances and peculiarvelocities to individual galaxies are derived, and it is shown that thevoid is approximately a 'Hubble Bubble' in which the near and far edgesare separating with the general expansion of the universe. At the 3sigma level, infall toward the Coma cluster is detected for a portion ofthe bubble wall. Limits on the net outflow from the void and infall intoComa are used to estimate Omega.
|Tests for alignment of galaxy position angles within a sheet of galaxies|
Measured position angles of 149 galaxies that lie in a sheet near thevoid in Corona Borealis are presented. The distribution of positions andposition angles is tested for alignment; none is detected.
|Studies of IRAS sources at high galactic latitudes. IV - New redshifts and the spectroscopic properties of IRAS galaxies|
New redshifts, H-alpha line fluxes, and optical continuum fluxes forIRAS galaxies are presented. Most of the galaxies show emission linesstronger than those found in optically selected spiral galaxies andcharacteristic of normal H II regions, suggesting a burst of starformation as the basic energy source. There is considerable reddeningtoward the emission-line regions and toward the unobserved UV sources,most of the energy emerging in the infrared. A minority of the casesshow high-excitation emission lines, and these are also distinguished bytheir infrared colors, typical luminosities, and emission-linestrengths. Type 2 Seyferts outnumber type 1s by two to one.
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