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Centro de Astrofísica da Universidade do Porto

The XMM Cluster Survey: evolution of the velocity dispersion – temperature relation over half a Hubble time

S. Wilson, M. Hilton, P. J. Rooney, C. Caroline, S. T. Kay, C. A. Collins, I. G. McCarthy, A. K. Romer, A Bermeo-Hernandez, R. Bernstein, D Gifford, D. Hollowood, B. Hoyle, T. Jeltema, A. Liddle, M. A. G. Maia, R. Mann, J. A. Mayers, N. Mehrtens, C. J. Miller, R. C. Nichol, R. Ogando, Benjamin Stahl, J. P. Stott, , P. A. Thomas, P. T. P. Viana, H. Wilcox, Luiz da Costa, M. Sahlén

Abstract
We measure the evolution of the velocity dispersion--temperature (σv--TX) relation up to z=1 using a sample of 38 galaxy clusters drawn from the extit{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 GMOS 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 normalisation is slightly negative, but not significantly different from zero (σv∝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.

Monthly Notices of the Royal Astronomical Society
Volume 463, Page 413
November 2016

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Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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