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|The UZC-SSRS2 Group Catalog|
We apply a friends-of-friends algorithm to the combined Updated ZwickyCatalog and Southern Sky Redshift Survey to construct a catalog of 1168groups of galaxies; 411 of these groups have five or more members withinthe redshift survey. The group catalog covers 4.69 sr, and all groupsexceed the number density contrast threshold, δρ/ρ=80. Wedemonstrate that the groups catalog is homogeneous across the twounderlying redshift surveys; the catalog of groups and their membersthus provides a basis for other statistical studies of the large-scaledistribution of groups and their physical properties. The medianphysical properties of the groups are similar to those for groupsderived from independent surveys, including the ESO Key Programme andthe Las Campanas Redshift Survey. We include tables of groups and theirmembers.
|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.
|Extensive Spiral Structure and Corotation Resonance|
Spiral density wave theories demand that grand-design spiral structurebe bounded, at most, between the inner and outer Lindblad resonances ofthe spiral pattern. The corotation resonance lies between the outer andthe inner Lindblad resonances. The locations of the resonances are atradii whose ratios to each other are rather independent of the shape ofthe rotation curve. The measured ratio of outer to inner extent ofspiral structure for a given spiral galaxy can be compared to thestandard ratio of corotation to inner Lindblad resonance radius. In thecase that the measured ratio far exceeds the standard ratio, it islikely that the corotation resonance is within the bright optical disk.Studying such galaxies can teach us how the action of resonances sculptsthe appearance of spiral disks. This paper reports observations of 140disk galaxies, leading to resonance ratio tests for 109 qualified spiralgalaxies. It lists candidates that have a good chance of having thecorotation resonance radius within the bright optical disk.
|Seyfert Galaxies With Companions: Orbital and Kinematic Clues to AGN Triggering|
This paper presents imaging and optical spectroscopy of paired Seyfertgalaxies and their companions. The aim is to seek common properties ofSeyfert galaxies in interacting systems, which might provide evidence ofAGN triggering in a way independent of the usual two-sample statisticswhich have proven ambiguous on this issue. Three kinds of comparisonhave been made-the kinds of interactions involving Seyfert galaxies, therelative luminosities of the Seyferts and their companions, and thelevel of kinematic disturbance as measured from rotation curves. (1)Dynamics and tidal features have been used to determine (or at leastlimit) the sense of orbital motion (direct/retrograde/polar with respectto the Seyfert galaxy's disk) for many of these pairs. There is noobviously preferred kind of interaction-direct, polar, and retrogradeencounters are all well represented, despite the gross differences indynamical response of a disk to these various kinds of encounter. To theextent that triggering of Seyfert nuclei occurs due to tidal encounters,the existence of a perturbation seems more important than its exactduration or detailed effects on the disk. However, the ratio of mergingto paired Seyferts is higher than for disk galaxies in general,consistent with more effective triggering of AGN in this specific phase;the implied time scale for enhanced occurrence during mergers is thesame as the timescape for merger remnants to appear as such, a fewdisk-edge crossing times (typically several times 10^8^ yr). (2) Seyfertnuclei occur preferentially in the brighter members of galaxy pairs, bya median of 0.93 mag after making the maximal correction forcontaminating nonstellar light in the nuclei. Only about 1/3 of thiseffect can be accounted for by the known tendency of Seyfert nuclei tooccur in more luminous galaxies. Enhancement of AGN by interactions isevidently more effective for more luminous galaxies (though this willalso be the case if both star formation and AGN occurrence are enhancedin the same galaxies). (3) The rotation curves of the paired Seyfertsshow systematically small regions of rising or solid-body rotationcompared to the disk radius, as a group comparable to Sa but verydifferent from Sb or Sc galaxies (even for Seyfert galaxies with Hubbletype later than Sa). There is weak evidence that this difference is alsopresent with respect to more isolated Seyfert galaxies. Despite theobvious utility of a dynamically disturbed disk for transport of angularmomentum and "feeding the monster," Seyfert galaxies in pairs actuallyhave smaller kinematic disturbances (measured by the maximum departurefrom a symmetric rotation curve, normalized to the full rotationamplitude) than found in a complete sample of non-Seyfert spirals inpairs.
|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.
|A case for H0 = 42 and Omega(0) = 1 using luminous spiral galaxies and the cosmological time scale test|
The two principal methods of finding the Hubble velocity-distance ratiosfor individual galaxies are compared, and it is shown that one route toH0 is flawed by selection effects when using flux-limited catalogs. Theproof is made by analyzing two sets of catalogs that reach differentapparent flux levels, so that selection effects are shown directly. Theoptical data on field spiral galaxies of the brightest van den Berghluminosity class are analyzed. Calibration using M31, M81, and M101which have Cepheid distances gives H0 = 42 + or - 11 km/s/Mpc. It isshown that all values of H0 derived by the method of assigning a fixedabsolute magnitude to any given distance indicator is subject tosystematic error, giving too large an H0 value if uncorrected for bias.The age of the globular clusters is adopted to be 13.5 + or - 1 Gyr, andthe age of the universe is put at 14.9 + or - 2 Gyr. A value of Omega(0)= 1.2 + 3 or - 0.9 with Lambda = 0 is obtained.
|H I survey of face-on galaxies - The frequency of distortions in H I disks|
The full results of an H I survey of face-on galaxies are presented andit is shown that narrow H I profiles are rare in normal spiral galaxies.This is due in part to the wider-than-expected range of the integraldispersion and in part to the frequent occurrence of large-scaledistortions in the H I disk. These factors reduce the number of galaxieswith half-power widths less than 30 km/s to about 24 percent of thosethat would occur if galaxies generally had quiescent, coplanar H Idisks. Two useful subsets may be drawn from this study of 212 face-ongalaxies with axial ratios greater than 0.87. Fifty-two spirals of allmorphological types have half-power widths smaller than 100 km/s and maybe used for studies that benefit from a small velocity spread and anenhanced beam-filling factor. About 40 galaxies have velocity widthsmuch larger than expected and are of interest in studies of dynamicallypeculiar systems.
|A survey of galaxy redshifts. IV - The data|
The complete list of the best available radial velocities for the 2401galaxies in the merged Zwicky-Nilson catalog brighter than 14.5mz and with b (II) above +40 deg or below -30 deg ispresented. Almost 60 percent of the redshifts are from the CfA surveyand are accurate to typically 35 km/s.
|Catalogue no.10 of nebulae discovered at the Warner observatory.|
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