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|Scalar potential model of redshift and discrete redshift|
On the galactic scale the universe is inhomogeneous and redshift z isoccasionally less than zero. A scalar potential model (SPM) that linksthe galaxy scale z to the cosmological scale z of the Hubble Law ispostulated. Several differences among galaxy types suggest that spiralgalaxies are Sources and that early type, lenticular, and irregulargalaxies are Sinks of a scalar potential field. The morphology-radiusand the intragalactic medium cluster observations support the movementof matter from Source galaxies to Sink galaxies. A cell structure ofgalaxy groups and clusters is proposed to resolve a paradox concerningthe scalar potential like the Olber’s paradox concerning light.For the sample galaxies, the ratio of the luminosity of Source galaxiesto the luminosity of Sink galaxies approaches 2.7 ± 0.1. Anequation is derived from sample data, which is anisotropic andinhomogeneous, relating z of and the distance D to galaxies. Thecalculated z has a correlation coefficient of 0.88 with the measured zfor a sample of 32 spiral galaxies with D calculated using Cepheidvariable stars. The equation is consistent with z < 0 observations ofclose galaxies. At low cosmological distances, the equation reduces to z≈ exp(KD)‑1 ≈ KD, where K is a constant, positive value. Theequation predicts z from galaxies over 18 Gpc distant approaches aconstant value on the order of 500. The SPM of z provides a physicalbasis for the z of particle photons. Further, the SPM qualitativelysuggests the discrete variations in z, which was reported by Tifft[Tifft, W.G., 1997. Astrophy. J. 485, 465] and confirmed by others, areconsistent with the SPM.
|The Colors of Dwarf Elliptical Galaxy Globular Cluster Systems, Nuclei, and Stellar Halos|
We present the results of a Hubble Space Telescope WFPC2 F555W and F814Wsurvey of 69 dwarf elliptical galaxies (dEs) in the Virgo and FornaxClusters and Leo Group. The V-I colors of the dE globular clusters,nuclei, and underlying field-star populations are used to trace the dEstar formation histories. We find that the dE globular clustercandidates are as blue as the metal-poor globular clusters of the MilkyWay. The observed correlation of the dE globular cluster systems' V-Icolor with the luminosity of the host dE is strong evidence that theglobular clusters were formed within the halos of dEs and do not have apregalactic origin. Assuming that the majority of dE clusters are old,the mean globular cluster color-host galaxy luminosity correlationimplies a cluster metallicity-galaxy luminosity relation of~L0.22+/-0.05B, which issignificantly shallower than the field-star metallicity-host galaxyluminosity relationship observed in Local Group dwarfs(~L0.4). The dE stellar envelopes are0.1-0.2 mag redder in V-I than their globular clusters and nuclei. Thiscolor offset implies separate star formation episodes within the dEs forthe clusters and field stars, while the very blue colors of two dEnuclei trace a third star formation event in those dEs less than 1 Gyrago.
|Galaxy Populations and Evolution in Clusters. IV. Deep H I Observations of Dwarf Elliptical Galaxies in the Virgo Cluster|
In this paper we present deep Arecibo H I and WIYN optical observationsof Virgo Cluster dwarf elliptical galaxies. Based on this data we arguethat a significant fraction of low-mass galaxies in the Virgo Clusterrecently underwent evolution. Our new observations consist of H I 21 cmline observations for 22 classified dE galaxies with optical radialvelocities consistent with membership in the Virgo Cluster. Clustermembers VCC 390 and VCC 1713 are detected with H I massesMHI=6×107 and 8×107Msolar, respectively, while MHI values in theremaining 20 dE galaxies have upper limits as low as~5×105 Msolar. We combine our results withthose for 26 other Virgo Cluster dE galaxies with H I observations inthe literature, seven of which have H I detection claims. New opticalimages from the WIYN telescope of five of these H I-detected dEgalaxies, along with archival data, suggest that seven of the claimeddetections are true H I detections, yielding a ~15% detection rate.These H I-detected, classified dE galaxies are preferentially locatednear the periphery of the Virgo Cluster. Three Virgo dE galaxies haveobserved H I velocity widths greater than 200 km s-1,possibly indicating the presence of a large dark matter content ortransient extended H I. We discuss the possible origins of these objectsand argue that they originate from field galaxies accreted onto highangular momentum orbits by Virgo in the last few Gyr. As a result ofthis, we argue, these galaxies are slowly transformed within the clusterby gradual gas-stripping processes, associated truncation of starformation, and passive fading of stellar populations. Low-mass,early-type cluster galaxies are therefore currently being produced asthe product of cluster environmental effects. We utilize our results ina simple model to estimate the recent (past 1-3 Gyr) average massaccretion rate into the Virgo Cluster, deriving a value of M~50Msolar yr-1.
|Galaxy Populations and Evolution in Clusters. I. Dynamics and the Origin of Low-Mass Galaxies in the Virgo Cluster|
Early-type dwarfs are the most common galaxy in the local universe, yettheir origin and evolution remain a mystery. Various cosmologicalscenarios predict that dwarf-like galaxies in dense areas are the firstto form and hence should be the oldest stellar systems in clusters. Byusing radial velocities of early-type dwarfs in the Virgo cluster wedemonstrate that these galaxies are not an old cluster population buthave signatures of production from the infall of field galaxies.Evidence of this includes the combined large dispersions andsubstructure in spatial and kinematic distributions for Virgo early-typedwarfs and a velocity dispersion ratio with giant ellipticals expectedfor virialized and accreted populations. We also argue that thesegalaxies cannot originate from accreted field dwarfs, but must havephysically evolved from a precursor population, of different morphology,that fell into Virgo some time in the past.
|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.
|Distances to 64 Virgo dwarf-elliptical galaxies and the depth in their spatial distribution|
We derive distances for 64 dwarf ellipticals (dEs) in the direction ofthe Virgo cluster's (VC) core, by means of the luminosity-profilecurvature (L-n) relationship and by means of their global scalelengths,which we find to be correlated with the shapes of theirsurface-brightness profiles. The great depth we find in the spatialdistribution of Virgo dEs is not consistent with a unimodal distributiondue to a single spherically symmetric concentration of galaxies. Thisdepth is also sufficient to explain much of the disagreement over theVC's distance, and thereby much of the Hubble-constant (H_0)controversy.
|The use of dwarf elliptical galaxies as distance indicators - The relative distances between Virgo, Fornax, and Centaurus|
Photometric parameters derived from surface photometry of dwarfelliptical galaxies are used to determine the relative distance betweenthe Virgo, Fornax, and Centaurus clusters. The study uses a sample ofabout 25 dwarf elliptical galaxies in each cluster. With Virgo as thefiducial cluster, it is found that R(Fornax)/R(Virgo) = 0.93 + or - 0.07and R(Centaurus)/R(Virgo) = 1.91 + or - 0.07. The results are in goodagreement with those obtained by Aaronson et al. (1989) using the IRTully-Fisher relation.
|Studies of the Virgo Cluster. II - A catalog of 2096 galaxies in the Virgo Cluster area.|
The present catalog of 2096 galaxies within an area of about 140 sq degapproximately centered on the Virgo cluster should be an essentiallycomplete listing of all certain and possible cluster members,independent of morphological type. Cluster membership is essentiallydecided by galaxy morphology; for giants and the rare class of highsurface brightness dwarfs, membership rests on velocity data. While 1277of the catalog entries are considered members of the Virgo cluster, 574are possible members and 245 appear to be background Zwicky galaxies.Major-to-minor axis ratios are given for all galaxies brighter than B(T)= 18, as well as for many fainter ones.
|A catalog of dwarf galaxies in Virgo|
A catalog listing the location, apparent angular diameter, type,estimated central light concentration, and estimated brightness of 846dwarf galaxies in a 200-deg-sq region in Virgo is presented. Thegalaxies comprise 634 ellipticals, 137 IC-3475-type galaxies, 73 dwarfspirals and irregulars, and two objects which are jets of normalgalaxies, and were found on nine long-exposure IIIa-J-emulsion platesmade with the 1.2-m-Schmidt telescope at Palomar Observatory from 1971to 1976. Concordances to other catalogs, tables of additionalparameters, maps, graphs, and photographs are provided. The projecteddistributions of normal and dwarf galaxies and the dependence ofapparent luminosity on central light concentration are discussed. It isfound that dwarf ellipticals and IC-3475-type galaxies are probablemembers of the Virgo cluster, while dwarf spirals and possibly dwarfirregulars are not.
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