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The thermal SZ power spectrum
- Klaus Dolag, Eiichiro Komatsu, Rashid Sunyaev
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- Journal:
- Proceedings of the International Astronomical Union / Volume 11 / Issue A29B / August 2015
- Published online by Cambridge University Press:
- 27 October 2016, p. 59
- Print publication:
- August 2015
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- Article
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The Magneticum Pathfinder (www.magneticum.org) cosmological, hydro-dynamical simulation (896h-1Mpc)3 follows in detail the thermal and chemical evolution of the ICM as well as the evolution of SMBHs and their associated feedback processes. We demonstrate that assuming cosmological parameters inferred from the CMB, the thermal SZ power spectrum as observed by PLANCK is well matched by the deep light-cones constructed from these cosmological simulations. The thermal SZ prediction from the full SZ maps are significantly exceeding previous templates at large l (e.g., l > 1000) and therefore predict a significantly larger contribution to the signal at l = 3000 compared to previous findings. The excess of positive values within the probability distribution of the thermal SZ signal within the simulated light-cone agrees with the one seen by PLANCK. This excess signal follows a power law shape with an index of roughly -3.2. The bulk of the thermal SZ signal originates from clusters and groups which form between z = 0 and z ≈ 2 where at high redshift (z > 1) significant part of the signal originates from proto-cluster regions, which are not yet virialized. The simulation predicts a mean fluctuating Compton Y value of 1.18 × 10-6, with a remaining contribution of almost 5 ×10-7 when removing contribution from halos above a virial mass of 1013 M⊙/h.
4 - Cosmology
- from Part One - Einstein's Triumph
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- By David Wands, University of Portsmouth, Roy Maartens, University of the Western Cape, Misao Sasaki, Kyoto University, Eiichiro Komatsu, Max-Planck-Institut für Astrophysik, Malcolm A. H. MacCallum, Queen Mary University of London
- Edited by Abhay Ashtekar, Pennsylvania State University, Beverly K. Berger, James Isenberg, University of Oregon, Malcolm MacCallum, University of Bristol
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- Book:
- General Relativity and Gravitation
- Published online:
- 05 June 2015
- Print publication:
- 01 June 2015, pp 162-232
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Summary
Introduction
David Wands and Roy Maartens
Our Universe provides the grandest arena in which to test General Relativity as a theory of space, time and gravity. It becomes essential to consider both the causal propagation of matter and radiation through space-time and the dynamical evolution of space-time if we are to construct a consistent theoretical framework in which to interpret astronomical observations on the largest observable scales. Einstein himself originally tried to construct a static cosmology but it was soon appreciated that the field equations of General Relativity naturally accommodate dynamical and evolving space-times. Einstein's own static model of a 3-sphere, balancing the gravitational pull of matter against a positive spatial curvature and a cosmological constant was shown to be poised between expansion and collapse and hence unstable to infinitesimal disturbance.
Friedmann and Lemaître showed that Einstein's field equations admit expanding- universe solutions, which have become the basis for modern cosmology, despite Einstein's initial dismissal of the solutions. However persuasive the theoretical models, empirical observations are, of course, necessary to determine the actual dynamics of our observable Universe; the work of Slipher and Hubble in the 1920s [1] persuaded scientists that in fact our Universe is expanding. The logical consequence of this expansion is that either our Universe was hotter and denser in the past (coming ultimately from a Hot Big Bang) or, perhaps, that energy had to be continually created as the universe expanded (the Steady State model). The discovery of the Cosmic Microwave Background (CMB) radiation by Penzias and Wilson in 1965 [2] convinced most astronomers that the Universe did in fact begin at a Hot Big Bang, a finite time in the past. This hot dense plasma, in thermal equilibrium at early times, also provides a setting for the freezing out of the light atomic nuclei as the universe cools below several million degrees Kelvin [3], although heavier elements must be formed later in stars.