The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Rebecca Bernstein - One of the best experts on this subject based on the ideXlab platform.
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the xmm cluster survey evolution of the velocity dispersion Temperature Relation over half a hubble time
Monthly Notices of the Royal Astronomical Society, 2016Co-Authors: Susan Wilson, Ian G. Mccarthy, Scott T. Kay, Matt Hilton, P. Rooney, Caroline Caldwell, A. Bermeo, C Collins, Kathy A Romer, Rebecca BernsteinAbstract:We measure the evolution of the velocity dispersion-Temperature (sigma(v)-T-X) Relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the Relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalization is slightly negative, but not significantly different from zero (sigma(v) alpha T0.86+/-0.14E(z)(-0.37+/-0.33)). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.
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The XMM Cluster Survey: evolution of the velocity dispersion–Temperature Relation over half a Hubble time
Monthly Notices of the Royal Astronomical Society, 2016Co-Authors: Susan Wilson, Ian G. Mccarthy, C.a. Collins, Scott T. Kay, A. Kathy Romer, Matt Hilton, P. Rooney, Caroline Caldwell, A. Bermeo, Rebecca BernsteinAbstract:We measure the evolution of the velocity dispersion-Temperature (sigma(v)-T-X) Relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the Relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalization is slightly negative, but not significantly different from zero (sigma(v) alpha T0.86+/-0.14E(z)(-0.37+/-0.33)). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.
C.a. Collins - One of the best experts on this subject based on the ideXlab platform.
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The XMM Cluster Survey: evolution of the velocity dispersion–Temperature Relation over half a Hubble time
Monthly Notices of the Royal Astronomical Society, 2016Co-Authors: Susan Wilson, Ian G. Mccarthy, C.a. Collins, Scott T. Kay, A. Kathy Romer, Matt Hilton, P. Rooney, Caroline Caldwell, A. Bermeo, Rebecca BernsteinAbstract:We measure the evolution of the velocity dispersion-Temperature (sigma(v)-T-X) Relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the Relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalization is slightly negative, but not significantly different from zero (sigma(v) alpha T0.86+/-0.14E(z)(-0.37+/-0.33)). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.
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The XMM Cluster Survey: Forecasting cosmological and cluster scaling-Relation parameter constraints
Monthly Notices of the Royal Astronomical Society, 2009Co-Authors: Martin Sahlén, C.a. Collins, Pedro T. P. Viana, Andrew R. Liddle, A. Kathy Romer, Michael Davidson, Mark Hosmer, E. J. Lloyd-davies, Kivanc Sabirli, Peter E. FreemanAbstract:We forecast the constraints on the values of sigma_8, Omega_m, and cluster scaling Relation parameters which we expect to obtain from the XMM Cluster Survey (XCS). We assume a flat Lambda-CDM Universe and perform a Monte Carlo Markov Chain analysis of the evolution of the number density of galaxy clusters that takes into account a detailed simulated selection function. Comparing our current observed number of clusters shows good agreement with predictions. We determine the expected degradation of the constraints as a result of self-calibrating the luminosity-Temperature Relation (with scatter), including Temperature measurement errors, and relying on photometric methods for the estimation of galaxy cluster redshifts. We examine the effects of systematic errors in scaling Relation and measurement error assumptions. Using only (T,z) self-calibration, we expect to measure Omega_m to +-0.03 (and Omega_Lambda to the same accuracy assuming flatness), and sigma_8 to +-0.05, also constraining the normalization and slope of the luminosity-Temperature Relation to +-6 and +-13 per cent (at 1sigma) respectively in the process. Self-calibration fails to jointly constrain the scatter and redshift evolution of the luminosity-Temperature Relation significantly. Additional archival and/or follow-up data will improve on this. We do not expect measurement errors or imperfect knowledge of their distribution to degrade constraints significantly. Scaling-Relation systematics can easily lead to cosmological constraints 2sigma or more away from the fiducial model. Our treatment is the first exact treatment to this level of detail, and introduces a new `smoothed ML' estimate of expected constraints.
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The XMM-NEWTON Ω project: I. The X-ray luminosity-Temperature Relation at z > 0.4
Astronomy & Astrophysics, 2004Co-Authors: D. H. Lumb, J.g. Bartlett, A.k. Romer, A. Blanchard, C.a. Collins, M. Giard, P. Marty, Robert C. Nichol, Douglas Burke, J. NevalainenAbstract:We describe XMM-Newton Guaranteed Time observations of a sample of eight high redshift (0.45< z < 0.62) clusters. The goal of these observations was to measure the luminosity and the Temperature of the clusters to a precision of 10%, leading to constraints on the possible evolution of the luminosity-Temperature (Lx-Tx) Relation, and ultimately on the values of the matter density, M, and, to a lesser extent, the cosmological constant . The clusters were drawn from the SHARC and 160 Square Degree (160SD) ROSAT surveys and span a bolometric (0.0-20 keV) luminosity range of 2.0 to 14.4 1044 ergs (H0=50, M=1, =0). Here we describe our data analysis techniques and present, for the first time with XMM-Newton, a Lx-Tx Relation. For each of the eight clusters in the sample, we have measured total (r < rvirial) bolometric luminosities, performed -model fits to the radial surface profiles and made spectral fits to a single Temperature isothermal model. We describe data analysis techniques that pay particular attention to background mitigation. We have also estimated Temperatures and luminosities for two known clusters (Abell 2246 and RX J1325.0-3814), and one new high redshift cluster candidate (XMMU J084701.8+345117), that were detected off-axis. Characterizing the Lx-Tx Relation as Lx = L6 ((T)/(6 keV)), we find L6=15.9 +7.6-5.2 1044 ergs and =2.70.4 for an =0.0, M =1.0, H0=50 km s-1 Mpc-1 cosmology at a typical redshift z 0.55. Comparing with the low redshift study by Markevitch (1998), we find to be in agreement, and assuming Lx-Tx to evolve as (1+z){A }, we find A=0.680.26 for the same cosmology and A= 1.52+0.26-0.27 for an =0.7, M=0.3 cosmology. Our A values are very similar to those found previously by Vikhlinin et al. (2002) using a compilation of Chandra observations of 0.39
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The XMM-NEWTON Omega Project: I. The X-ray Luminosity - Temperature Relation at z>0.4
Astronomy and Astrophysics - A&A, 2004Co-Authors: D. H. Lumb, J.g. Bartlett, A.k. Romer, A. Blanchard, D.j. Burke, C.a. Collins, R.c. Nichol, M. Giard, P. Marty, J. NevalainenAbstract:We describe XMM-Newton Guaranteed Time observations of a sample of eight high redshift (0.45 < z < 0.62) clusters. The goal of these observations was to measure the luminosity and the Temperature of the clusters to a precision of 10%, leading to constraints on the possible evolution of the luminosity--Temperature Relation, and ultimately on the values of the matter density, Omega_M and, to a lesser extent, the cosmological constant Omega_L. The clusters were drawn from the SHARC and 160 Square Degree (160SD) ROSAT surveys. Here we describe our data analysis techniques and present, for the first time with XMM-Newton,Lx-Tx Relation. For each of the eight clusters in the sample, we have measured total bolometric luminosities, performed beta-model fits to the radial surface profiles and made spectral fits to a single Temperature isothermal model. We describe data analysis techniques that pay particular attention to background mitigation. Characterizing the Lx-Tx Relation as Lx = L_{6} (T/6keV)^{alpha},we find L_{6}=16.8 +7.6/-5.2 10^{44} erg/s and alpha=2.7 +/-0.4 for a EdS H=50 cosmology at a typical redshift z =0.55. Comparing with the low redshift study by Markevitch, assuming L-T to evolve as (1+z)^A, we find A=0.68 +/-0.26 for the same cosmology and A=1.52 +0.26/-0.27 for a concordance cosmology. We conclude that there is now evidence from both XMM-Newton and Chandra for an evolutionary trend in the L-T Relation. Our observations lend support to the robustness and completeness of the SHARC and 160SD surveys.
Ian G. Mccarthy - One of the best experts on this subject based on the ideXlab platform.
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the xmm cluster survey evolution of the velocity dispersion Temperature Relation over half a hubble time
Monthly Notices of the Royal Astronomical Society, 2016Co-Authors: Susan Wilson, Ian G. Mccarthy, Scott T. Kay, Matt Hilton, P. Rooney, Caroline Caldwell, A. Bermeo, C Collins, Kathy A Romer, Rebecca BernsteinAbstract:We measure the evolution of the velocity dispersion-Temperature (sigma(v)-T-X) Relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the Relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalization is slightly negative, but not significantly different from zero (sigma(v) alpha T0.86+/-0.14E(z)(-0.37+/-0.33)). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.
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The XMM Cluster Survey: evolution of the velocity dispersion–Temperature Relation over half a Hubble time
Monthly Notices of the Royal Astronomical Society, 2016Co-Authors: Susan Wilson, Ian G. Mccarthy, C.a. Collins, Scott T. Kay, A. Kathy Romer, Matt Hilton, P. Rooney, Caroline Caldwell, A. Bermeo, Rebecca BernsteinAbstract:We measure the evolution of the velocity dispersion-Temperature (sigma(v)-T-X) Relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the Relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalization is slightly negative, but not significantly different from zero (sigma(v) alpha T0.86+/-0.14E(z)(-0.37+/-0.33)). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.
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The Cluster Gas Mass - Temperature Relation: Evidence for a High Level of Preheating
The Astrophysical Journal, 2002Co-Authors: Ian G. Mccarthy, Arif Babul, Michael L. BaloghAbstract:Recent X-ray observations have been used to demonstrate that the cluster gas mass-Temperature Relation is steeper than theoretical self-similar predictions drawn from numerical simulations that consider the evolution of the cluster gas through the effects of gravity and shock heating alone. One possible explanation for this is that the gas mass fraction is not constant across clusters of different Temperature, as is usually assumed. Observationally, however, there is no compelling evidence for gas mass fraction variation, especially in the case of hot clusters. Seeking an alternative physical explanation for the observed trends, we investigate the role in the cluster gas mass - Temperature Relation of the preheating of the intracluster medium by some arbitrary source for clusters with emission-weighted mean Temperatures of greater than about 3 keV. Making use of the physically-motivated, analytic models developed in 2002 by Babul and coworkers, we find that preheating does, indeed, lead to a steeper Relation. This is in agreement with previous theoretical studies on the Relation. However, in apparent conflict with these studies, we argue that a ``high'' level of entropy injection is required to match observations. In particular, an entropy floor of greater than about 300 keV cm^2 is required. We also present a new test, namely, the study of the Relation within different fixed radii. This allows one to indirectly probe the density profiles of clusters, since it samples different fractions of the virial radius for clusters of different Temperature. This test also confirms that a high level of preheating is required to match observations.
Scott T. Kay - One of the best experts on this subject based on the ideXlab platform.
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the xmm cluster survey evolution of the velocity dispersion Temperature Relation over half a hubble time
Monthly Notices of the Royal Astronomical Society, 2016Co-Authors: Susan Wilson, Ian G. Mccarthy, Scott T. Kay, Matt Hilton, P. Rooney, Caroline Caldwell, A. Bermeo, C Collins, Kathy A Romer, Rebecca BernsteinAbstract:We measure the evolution of the velocity dispersion-Temperature (sigma(v)-T-X) Relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the Relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalization is slightly negative, but not significantly different from zero (sigma(v) alpha T0.86+/-0.14E(z)(-0.37+/-0.33)). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.
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The XMM Cluster Survey: evolution of the velocity dispersion–Temperature Relation over half a Hubble time
Monthly Notices of the Royal Astronomical Society, 2016Co-Authors: Susan Wilson, Ian G. Mccarthy, C.a. Collins, Scott T. Kay, A. Kathy Romer, Matt Hilton, P. Rooney, Caroline Caldwell, A. Bermeo, Rebecca BernsteinAbstract:We measure the evolution of the velocity dispersion-Temperature (sigma(v)-T-X) Relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the Relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalization is slightly negative, but not significantly different from zero (sigma(v) alpha T0.86+/-0.14E(z)(-0.37+/-0.33)). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.
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Nature versus nurture: the curved spine of the galaxy cluster X‐ray luminosity–Temperature Relation
Monthly Notices of the Royal Astronomical Society, 2008Co-Authors: Will Hartley, L. Gazzola, Frazer R. Pearce, Scott T. Kay, Peter A. ThomasAbstract:The physical processes that define the spine of the galaxy cluster X-ray luminosity?Temperature (L?T) Relation are investigated using a large hydrodynamical simulation of the universe. This simulation models the same volume and phases as the millennium simulation and has a linear extent of 500 h-1 Mpc. We demonstrate that mergers typically boost a cluster along but also slightly below the L?T Relation. Due to this boost, we expect that all of the very brightest clusters will be near the peak of a merger. Objects from near the top of the L?T Relation tend to have assembled much of their mass earlier than an average halo of similar final mass. Conversely, objects from the bottom of the Relation are often experiencing an ongoing or recent merger.
Susan Wilson - One of the best experts on this subject based on the ideXlab platform.
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the xmm cluster survey evolution of the velocity dispersion Temperature Relation over half a hubble time
Monthly Notices of the Royal Astronomical Society, 2016Co-Authors: Susan Wilson, Ian G. Mccarthy, Scott T. Kay, Matt Hilton, P. Rooney, Caroline Caldwell, A. Bermeo, C Collins, Kathy A Romer, Rebecca BernsteinAbstract:We measure the evolution of the velocity dispersion-Temperature (sigma(v)-T-X) Relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the Relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalization is slightly negative, but not significantly different from zero (sigma(v) alpha T0.86+/-0.14E(z)(-0.37+/-0.33)). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.
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The XMM Cluster Survey: evolution of the velocity dispersion–Temperature Relation over half a Hubble time
Monthly Notices of the Royal Astronomical Society, 2016Co-Authors: Susan Wilson, Ian G. Mccarthy, C.a. Collins, Scott T. Kay, A. Kathy Romer, Matt Hilton, P. Rooney, Caroline Caldwell, A. Bermeo, Rebecca BernsteinAbstract:We measure the evolution of the velocity dispersion-Temperature (sigma(v)-T-X) Relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the Relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalization is slightly negative, but not significantly different from zero (sigma(v) alpha T0.86+/-0.14E(z)(-0.37+/-0.33)). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.
