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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
The Infall Region Of Abell 576: Independent Mass And Light Profiles, Kenneth Rines, Margaret J. Geller, Antonaldo Diaferio, Joseph J. Mohr, Gary A. Wegner
The Infall Region Of Abell 576: Independent Mass And Light Profiles, Kenneth Rines, Margaret J. Geller, Antonaldo Diaferio, Joseph J. Mohr, Gary A. Wegner
Dartmouth Scholarship
We describe observations of the nearby (cz = 11,487 km s-1) cluster of galaxies Abell 576 beyond the virial radius and into the infall region where galaxies are on their first or second pass through the cluster. Using 1057 redshifts, we use the infall pattern in redshift space to determine the mass profile of A576 to a radius of ~4 h-1 Mpc. This mass estimation technique makes no assumptions about the equilibrium state of the cluster. Within ~1 h-1 Mpc, the mass profile we derive exceeds that determined from X-ray observations by a factor of …
Rosat Hri And Asca Observations Of The Spiral Galaxy Ngc 6946 And Its Northeast Complex Of Luminous Supernova Remnants, Eric M. Schlegel, William P. Blair, Robert A. Fesen
Rosat Hri And Asca Observations Of The Spiral Galaxy Ngc 6946 And Its Northeast Complex Of Luminous Supernova Remnants, Eric M. Schlegel, William P. Blair, Robert A. Fesen
Dartmouth Scholarship
Analysis of 80 ks ASCA and 60 ks ROSAT HRI observations of the face-on spiral galaxy NGC 6946 are presented. The ASCA image is the first observation of this galaxy above ~2 keV. Diffuse emission may be present in the inner ~4' extending to energies above ~2–3 keV. In the HRI data, 14 pointlike sources are detected, the brightest two being a source very close to the nucleus and a source to the northeast that corresponds to a luminous complex of interacting supernova remnants (SNRs). We detect a point source that lies ~30'' west of the SNR complex but with …
The Warps Survey - Iv. The X-Ray Luminosity-Temperature Relation Of High-Redshift Galaxy Clusters, B. W. Fairley, L. R. Jones, C. Scharf, H. Ebeling, E. Perlman, D. Horner, G. Wegner, M. Malkan
The Warps Survey - Iv. The X-Ray Luminosity-Temperature Relation Of High-Redshift Galaxy Clusters, B. W. Fairley, L. R. Jones, C. Scharf, H. Ebeling, E. Perlman, D. Horner, G. Wegner, M. Malkan
Dartmouth Scholarship
We present a measurement of the cluster X-ray luminosity-temperature (L-T) relation out to high redshift (z∼0.8). Combined ROSAT PSPC spectra of 91 galaxy clusters detected in the Wide Angle ROSAT Pointed Survey (WARPS) are simultaneously fitted in redshift and luminosity bins. The resulting temperature and luminosity measurements of these bins, which occupy a region of the high-redshift L-T relation not previously sampled, are compared with existing measurements at low redshift in order to constrain the evolution of the L-T relation. We find the best fit to low-redshift (z<0.2) cluster data, at T …
Redshift-Distance Survey Of Early-Type Galaxies: Dipole Of The Velocity Field, L. N. Da Costa, M. Bernardi, M. V. Alonso, G. Wegner
Redshift-Distance Survey Of Early-Type Galaxies: Dipole Of The Velocity Field, L. N. Da Costa, M. Bernardi, M. V. Alonso, G. Wegner
Dartmouth Scholarship
We use the recently completed redshift-distance survey of nearby early-type galaxies (ENEAR) to measure the dipole component of the peculiar velocity field to a depth of cz ~ 6000 km s-1. The sample consists of 1145 galaxies brighter than mB = 14.5 and with cz ≤ 7000 km s-1, uniformly distributed over the whole sky, and 129 fainter cluster galaxies within the same volume. Most of the Dn-σ distances were obtained from new spectroscopic and photometric observations conducted by this project, ensuring the homogeneity of the data over the whole sky. These 1274 galaxies are objectively assigned …
Redshift-Distance Survey Of Early-Type Galaxies. I. Sample Selection, Properties, And Completeness, L. N. Da Costa, M. Bernardi, M. V. Alonso, G. Wegner
Redshift-Distance Survey Of Early-Type Galaxies. I. Sample Selection, Properties, And Completeness, L. N. Da Costa, M. Bernardi, M. V. Alonso, G. Wegner
Dartmouth Scholarship
This is the first in a series of papers describing the recently completed all-sky redshift-distance survey of Early-type NEARby galaxies (ENEAR) carried out for peculiar velocity analysis. The sample is divided into two parts and consists of 1607 elliptical and lenticular galaxies with cz ≤ 7000 km s-1 and with blue magnitudes brighter than mB = 14.5 (ENEARm) and of galaxies in clusters (ENEARc). Galaxy distances based on the Dn-σ and fundamental plane (FP) relations are now available for 1359 and 1107 ENEARm galaxies, respectively, with roughly 80% based on new data gathered by …
Enear Redshift-Distance Survey: Cosmological Constraints, Stefano Borgani, Mariangela Bernardi, Luiz N. Da Costa, Gary Wegner
Enear Redshift-Distance Survey: Cosmological Constraints, Stefano Borgani, Mariangela Bernardi, Luiz N. Da Costa, Gary Wegner
Dartmouth Scholarship
We present an analysis of the ENEAR sample of peculiar velocities of field and cluster elliptical galaxies, obtained with Dn-σ distances. We use the velocity correlation function ψ1(r) to analyze the statistics of the field object's velocities, while the analysis of the cluster data is based on the estimate of their rms peculiar velocity Vrms. The results are compared with predictions from cosmological models using linear theory. The statistics of the model velocity field is parameterized by the amplitude η8 = σ8Ω and by the shape parameter Γ of the cold dark matter-like power spectrum. …
Correlation Analysis Of Sfi Peculiar Velocities, Stefano Borgani, Luiz N. Da Costa, Idit Zehavi, Riccardo Giovanelli, Martha P. Haynes, Wolfram Freudling, Gary Wegner, John J. Salzer
Correlation Analysis Of Sfi Peculiar Velocities, Stefano Borgani, Luiz N. Da Costa, Idit Zehavi, Riccardo Giovanelli, Martha P. Haynes, Wolfram Freudling, Gary Wegner, John J. Salzer
Dartmouth Scholarship
We present results of a statistical analysis of the SFI catalog of peculiar velocities, a recently completed survey of spiral field galaxies with I-band Tully-Fisher distances. The velocity field statistic utilized is the velocity correlation function, ψ1(r), originally introduced by Górski et al. The analysis is performed in redshift space so as to circumvent potential ambiguities connected with inhomogeneous Malmquist bias corrections. The results from the SFI sample are compared with linear-theory predictions for a class of cosmological models. We generate a large set of mock samples, extracted from N-body simulations, which are used …