Federal Register, Volume 74, Number 35, February 24, 2009, Pages 8139-8464 (open access)

Federal Register, Volume 74, Number 35, February 24, 2009, Pages 8139-8464

Daily publication of the U.S. Office of the Federal Register contains rules and regulations, proposed legislation and rule changes, and other notices, including "Presidential proclamations and Executive Orders, Federal agency documents having general applicability and legal effect, documents required to be published by act of Congress, and other Federal agency documents of public interest" (p. ii). Table of Contents starts on page iii.
Date: February 24, 2009
Creator: United States. Office of the Federal Register.
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
Characterizing the Properties of Clusters of Galaxies As a Function of Luminosity and Redshift (open access)

Characterizing the Properties of Clusters of Galaxies As a Function of Luminosity and Redshift

Abstract: We report the application of the new Monte Carlo method, Smoothed Particle Inference (SPI, described in a pair of companion papers), towards analysis and interpretation of X-ray observations of clusters of galaxies with the XMM-Newton satellite. Our sample consists of publicly available well-exposed observations of clusters at redshifts z > 0.069, totaling 101 objects. We determine the luminosity and temperature structure of the X-ray emitting gas, with the goal to quantify the scatter and the evolution of the L{sub X} - T relation, as well as to investigate the dependence on cluster substructure with redshift. This work is important for the establishment of the potential robustness of mass estimates from X-ray data which in turn is essential towards the use of clusters for measurements of cosmological parameters. We use the luminosity and temperature maps derived via the SPI technique to determine the presence of cooling cores, via measurements of luminosity and temperature contrast. The L{sub X}-T relation is investigated, and we confirm that L{sub X} {proportional_to} T{sup 3}. We find a weak redshift dependence ({proportional_to} (1 + z){sup {beta}{sub LT}}, {beta}{sub LT} = 0.50 {+-} 0.34), in contrast to some Chandra results. The level of dynamical activity is established …
Date: February 24, 2009
Creator: Andersson, K.; Peterson, J. R.; Madejski, G. & Goobar, A.
Object Type: Article
System: The UNT Digital Library
The Altus Times (Altus, Okla.), Vol. 111, No. 164, Ed. 1 Tuesday, February 24, 2009 (open access)

The Altus Times (Altus, Okla.), Vol. 111, No. 164, Ed. 1 Tuesday, February 24, 2009

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: February 24, 2009
Creator: Bush, Michael
Object Type: Newspaper
System: The Gateway to Oklahoma History