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Full-Text Articles in Physical Sciences and Mathematics
The Motions Of Clusters Of Galaxies And The Dipoles Of The Peculiar Velocity Field, Riccardo Giovanelli, Martha P. Haynes, John J. Salzer, Gary Wegner
The Motions Of Clusters Of Galaxies And The Dipoles Of The Peculiar Velocity Field, Riccardo Giovanelli, Martha P. Haynes, John J. Salzer, Gary Wegner
Dartmouth Scholarship
In preceding papers of this series, TF relations for galaxies in 24 clusters with radial velocities between 1000 and 9200 km s-1 (SCI sample) were obtained, a Tully-Fisher (TF) template relation was constructed, and mean offsets of each cluster with respect to the template were obtained. Here, an estimate of the line-of-sight peculiar velocities of the clusters and their associated errors are given. It is found that cluster peculiar velocities in the cosmic microwave background reference frame do not exceed 600 km s-1 and that their distribution has a line-of-sight dispersion of 300 km s-1, suggesting …
Cluster Versus Field Elliptical Galaxies And Clues On Their Formation, Mariangela Bernardi, Alvio Renzini, Luiz N. Da Costa, Gary Wegner
Cluster Versus Field Elliptical Galaxies And Clues On Their Formation, Mariangela Bernardi, Alvio Renzini, Luiz N. Da Costa, Gary Wegner
Dartmouth Scholarship
Using new observations for a sample of 931 early-type galaxies, we investigate whether the Mg2-σ0 relation shows any dependence on the local environment. The galaxies have been assigned to three different environments depending on the local overdensity (clusters, groups, and field); we used our complete redshift database to guide the assignment of galaxies. It is found that cluster, group, and field early-type galaxies follow almost identical Mg2-σ0 relations, with the largest Mg2 zero-point difference (clusters minus field) being only 0.007±0.002 mag. No correlation of the residuals is found with the morphological type or …
Peculiar Velocity Dipoles Of Field Galaxies, Riccardo Giovanelli, Martha P. Haynes, Wolfram Freudling, Luiz N. Da Costa, John J. Salzer, Gary Wegner
Peculiar Velocity Dipoles Of Field Galaxies, Riccardo Giovanelli, Martha P. Haynes, Wolfram Freudling, Luiz N. Da Costa, John J. Salzer, Gary Wegner
Dartmouth Scholarship
The Tully-Fisher (TF) relation is applied to obtain peculiar velocities of field spiral galaxies and to calculate dipoles of the peculiar velocity field to cz8000 km s-1. The field galaxy sample is spatially coextensive with and completely independent of a cluster sample, for which dipole characteristics are given in a separate paper. Dipoles of the peculiar velocity field are obtained separately by applying (1) an inverse version of the TF relation and selecting galaxies by redshift windowing and (2) a direct TF relation, with velocities corrected for the inhomogeneous Malmquist bias and windowing galaxies by TF distance. …
A V And I Ccd Mosaic Survey Of The Ursa Minor Dwarf Spheroidal Galaxy, J. T. Kleyna, M. J. Geller, S. J. Kenyon, M. J. Kurtz, J. R. Thorstensen
A V And I Ccd Mosaic Survey Of The Ursa Minor Dwarf Spheroidal Galaxy, J. T. Kleyna, M. J. Geller, S. J. Kenyon, M. J. Kurtz, J. R. Thorstensen
Dartmouth Scholarship
We discuss a Johnson-Cousins V- and I-band CCD mosaic survey of the Ursa Minor dwarf spheroidal galaxy (dSph) to V ~ 22. We covered UMi with 27 105 × 105 overlapping CCD frames, each frame consisting of two 300 s exposures in each of V and I. We also observed several regions ~3° from UMi to obtain an estimate of contamination by galaxies and Galactic stars. We report the first H-R diagram of an entire dSph. Separation of dwarf stars from foreground stars by color allows a robust estimation of the structural parameters of UMi. We examine …
A Late-Time Optical Detection Of Sn 1985l In Ngc 5033, Robert A. Fesen
A Late-Time Optical Detection Of Sn 1985l In Ngc 5033, Robert A. Fesen
Dartmouth Scholarship
An apparent late-time optical recovery of SN 1985L (Type II-L) in the Sb galaxy NGC 5033 is presented and discussed. An Hα emission point source is found within 1'' of both SN 1985L's historically reported position 70'' west and 55'' north of NGC 5033's center and its late-time, radio-measured position. This Hα source is not visible on V-band or narrow red continuum (7000 ± 125 Å) images, but is detected using a 6510 Å filter (FWHM = 30 Å). Its detection at 6510 Å can be attributed to blueshifted Hα emission because of a broad (±5000 km s-1 …
The Warps Survey. Ii. The Log N –Log S Relation And The X‐Ray Evolution Of Low‐Luminosity Clusters Of Galaxies, L. R. Jones, C. Scharf, H. Ebeling, E. Perlman, G. Wegner, M. Malkan, D. Horner
The Warps Survey. Ii. The Log N –Log S Relation And The X‐Ray Evolution Of Low‐Luminosity Clusters Of Galaxies, L. R. Jones, C. Scharf, H. Ebeling, E. Perlman, G. Wegner, M. Malkan, D. Horner
Dartmouth Scholarship
The strong negative evolution observed in previous X-ray-selected surveys of clusters of galaxies is evidence in favor of hierarchical models of the growth of structure in the universe. A large recent survey has, however, contradicted the low-redshift results, finding no evidence for evolution at z < 0.3. Here we present the first results from an X-ray-selected, flux- and surface brightness-limited deep survey for high-redshift clusters and groups of galaxies based on ROSAT PSPC pointed data. The log N-log S relation of all clusters in this survey is consistent with that of most previous surveys, but it occupies a flux range not previously covered (greater than 6 × 10-14 ergs cm-2 s-1 total flux in the 0.5-2 keV band). At high redshifts ( …