86 research outputs found
Chandra Measurements of a Complete Sample of X-ray Luminous Galaxy Clusters: The Luminosity-Mass Relation
We present the results of work involving a statistically complete sample of
34 galaxy clusters, in the redshift range 0.15z0.3 observed with
. We investigate the luminosity-mass () relation for the cluster
sample, with the masses obtained via a full hydrostatic mass analysis. We
utilise a method to fully account for selection biases when modeling the
relation, and find that the relation is significantly different than the
relation modelled when not account for selection effects. We find that the
luminosity of our clusters is 2.20.4 times higher (when accounting for
selection effects) than the average for a given mass, its mass is 30% lower
than the population average for a given luminosity. Equivalently, using the
relation measured from this sample without correcting for selection biases
would lead to the underestimation by 40% of the average mass of a cluster with
a given luminosity. Comparing the hydrostatic masses to mass estimates
determined from the parameter, we find that they are entirely
consistent, irrespective of the dynamical state of the cluster.Comment: 31 pages, 43 figures, accepted for publication in MNRA
Sunyaev-Zel'dovich-measured Pressure Profiles from the Bolocam X-Ray/SZ Galaxy Cluster Sample
We describe Sunyaev-Zel'dovich (SZ) effect measurements and analysis of the intracluster medium (ICM) pressure profiles of a set of 45 massive galaxy clusters imaged using Bolocam at the Caltech Submillimeter Observatory. We deproject the average pressure profile of our sample into 13 logarithmically spaced radial bins between 0.07R_(500) and 3.5R_(500), and we find that a generalized Navarro, Frenk, and White (gNFW) profile describes our data with sufficient goodness-of-fit and best-fit parameters (C_(500), α, β, γ, P_0 = 1.18, 0.86, 3.67, 0.67, 4.29). We use X-ray data to define cool-core and disturbed subsamples of clusters, and we constrain the average pressure profiles of each of these subsamples. We find that, given the precision of our data, the average pressure profiles of disturbed and cool-core clusters are consistent with one another at R≳ 0.15R_(500), with cool-core systems showing indications of higher pressure at R≾ 0.15R_(500). In addition, for the first time, we place simultaneous constraints on the mass scaling of cluster pressure profiles, their ensemble mean profile, and their radius-dependent intrinsic scatter between 0.1R_(500) and 2.0R_(500). The scatter among profiles is minimized at radii between ≃ 0.2R_(500) and ≃ 0.5R_(500), with a value of ≃ 20%. These results for the intrinsic scatter are largely consistent with previous analyses, most of which have relied heavily on X-ray derived pressures of clusters at significantly lower masses and redshifts compared to our sample. Therefore, our data provide further evidence that cluster pressure profiles are largely universal with scatter of ≃ 20%-40% about the universal profile over a wide range of masses and redshifts
TRABALHO ESCRAVO CONTEMPORÂNEO: A CONSTRUÇÃO SOCIAL DE UM PROBLEMA PÚBLICO NO NORTE FLUMINENSE
Multi-instrument multi-scale experimental damage mechanics for fibre reinforced composites
© Published under licence by IOP Publishing Ltd. Reliable investigation of damage in fibre reinforced composites requires concurrent in- and ex-situ application of multiple instruments at different scale: digital image correlation, acoustic emission registration, optical/electron microscopy, C-scan, X-ray imaging and micro-computed tomography. The multi-instrument experimental mechanics allows detailed damage monitoring and inspection
The Dynamics of Adverse Incorporation in Global Production Networks: Poverty, Vulnerability and ‘Slave Labour’ in Brazil
Damage signature of fatigued fabric reinforced plastics in the pulsed ultrasonic polar scan
This study investigates the use of both the amplitude and time-of-flight based pulsed ultrasonic polar scan (P-UPS) for the nondestructive detection and evaluation of fatigue damage in fiber reinforced composites. Several thermoplastic carbon fabric reinforced PPS specimens (CETEX), loaded under various fatigue conditions, have been scanned at multiple material spots according to the P-UPS technique in order to extract material degradation in a quantitative way.
The P-UPS results indicate that shear dominated fatigued carbon/PPS goes with a reduction of shear properties combined with large fiber distortions. The P-UPS results of the tension-tension fatigued carbon/PPS samples on the other hand reveal a directional degradation of the stiffness properties, reaching a maximum reduction of -12.8% along the loading direction. The P-UPS extracted damage characteristics are fully supported by simulations, conventional destructive tests as well as visual inspection. The results demonstrate the excellent capability of the P-UPS method for nondestructively assessing and quantifying both shear-dominated and tension-tension fatigue damage in fabric reinforced plastics
Effects of changes in micro-weather conditions on structural features, total protein and carbohydrate content in leaves of the Atlantic rain forest tree golden trumpet (Tabebuia chrysotricha)
Über den Zusammenhang zwischen Sekundärstruktur eines Aluminiumhydroxyds und Immunisierungsvermögen eines daran adsorbierten Antigens
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