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X-ray observations of galaxy clusters potentially provide powerful cosmological probes if systematics due to our incomplete knowledge of the intracluster medium (ICM) physics are understood and controlled. In this paper, we present mock…

Astrophysics · Physics 2008-11-26 Daisuke Nagai , Alexey Vikhlinin , Andrey V. Kravtsov

We use Enzo, a hybrid Eulerian AMR/N-body code including non-gravitational heating and cooling, to explore the morphology of the X-ray gas in clusters of galaxies and its evolution in current generation cosmological simulations. We employ…

Astrophysics · Physics 2010-11-11 Tesla E. Jeltema , Eric J. Hallman , Jack O. Burns , Patrick M. Motl

The dependence of galaxy clustering on local density provides an effective method for extracting non-Gaussian information from galaxy surveys. The two-point correlation function (2PCF) provides a complete statistical description of a…

We propose an extension of the semi-analytical solutions derived by Lin et al. (1965) describing the two-dimensional homologous collapse of a self-gravitating rotating cloud having uniform density and spheroidal shape, which includes…

Astrophysics · Physics 2009-11-10 P. Hennebelle

We investigate classes of shear-free cosmological dust models with irrotational fluid flows within the framework of $f(T)$ gravity. In particular, we use the $1 + 3$ covariant formalism and present the covariant linearised evolution and…

General Relativity and Quantum Cosmology · Physics 2022-07-27 Heba Sami , Shambel Sahlu , Amare Abebe , Peter K. S. Dunsby

This study focuses on statistical inference for compound models of the form $X=\xi_1+\ldots+\xi_N$, where $N$ is a random variable denoting the count of summands, which are independent and identically distributed (i.i.d.) random variables…

Statistics Theory · Mathematics 2025-07-22 Denis Belomestny , Ekaterina Morozova , Vladimir Panov

We calculate renormalization group flow equations for the linear sigma-model in large N_c approximation. The flow equations decouple and can be solved analytically. The solution is equal to a self consistent solution of the NJL model in the…

High Energy Physics - Phenomenology · Physics 2009-11-07 J. Meyer , K. Schwenzer , H. -J. Pirner , A. Deandrea

We study the dynamics of small inhomogeneities in an expanding universe collapsing to form bound structures using full solutions of the Einstein-Vlasov (N-body) equations. We compare these to standard Newtonian N-body solutions using…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-28 William E. East , Radosław Wojtak , Frans Pretorius

We apply and extend standard tools for void statistics to cosmological simulations that solve Einstein's equations with numerical relativity (NR). We obtain a simulated void catalogue without Newtonian approximations, using a new watershed…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-10 Michael J. Williams , Hayley J. Macpherson , David L. Wiltshire , Chris Stevens

As a follow-up of a previous work of the authors, this work considers {\em uniform global time-renormalization functions} for the {\em gravitational} $N$-body problem. It improves on the estimates of the radii of convergence obtained…

Numerical Analysis · Mathematics 2021-07-22 Mikel Antoñana , Philippe Chartier , Ander Murua

We review the role played by long-distance symmetries within the context of the similarity renormalization group approach. This is based on phase-shift-preserving continuous unitary transformations that evolve Hamiltonians with a cutoff on…

Nuclear Theory · Physics 2013-02-19 E. Ruiz Arriola , V. S. Timoteo , S. Szpigel

Local nonlinear approximations to the growth of cosmic perturbations are developed, resulting in relations, at a given epoch, between the peculiar velocity and gravity fields and their gradients. Only the equation of motion is approximated,…

Astrophysics · Physics 2009-10-22 Paul J. Mancinelli , Amos Yahil

Recently, the variation of the Planck mass in the General Relativistic Einstein-Hilbert action was proposed as a self-tuning mechanism of the cosmological constant, preventing Standard Model vacuum energy from freely gravitating and…

General Relativity and Quantum Cosmology · Physics 2021-11-02 Daniel Sobral-Blanco , Lucas Lombriser

We have investigated the scale-invariant solutions of the BBGKY equations for spatial correlation functions of cosmological density fluctuations and the mean relative peculiar velocity in the strongly nonlinear regime. It is found that the…

Astrophysics · Physics 2009-10-28 Taihei Yano , Naoteru Gouda

Numerical simulations of self-gravitating systems are generally based on N-body codes, which solve the equations of motion of a large number of interacting particles. This approach suffers from poor statistical sampling in regions of low…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-27 Giovanni Manfredi , Jean-Louis Rouet , Bruce Miller , Yui Shiozawa

An important open question in cosmology is the degree to which the Friedmann-Lemaitre-Robertson-Walker (FLRW) solutions of Einstein's equations are able to model the large-scale behaviour of the locally inhomogeneous observable universe. We…

General Relativity and Quantum Cosmology · Physics 2013-08-29 Timothy Clifton , Kjell Rosquist , Reza Tavakol

We employ the techniques of the Functional Renormalization Group in string theory, in order to derive an effective mini-superspace action for cosmological backgrounds to all orders in the string scale $\alpha'$. To this end, T-duality plays…

High Energy Physics - Theory · Physics 2021-06-11 Ivano Basile , Alessia Platania

We present a pilot X-ray study of the five most massive ($M_{500}>5 \times 10^{14} M_{\odot}$), distant (z~1), galaxy clusters detected via the Sunyaev-Zeldovich effect. We optimally combine XMM-Newton and Chandra X-ray observations by…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-01 I. Bartalucci , M. Arnaud , G. W. Pratt , J. Démoclès , R. F. J. van der Burg , P. Mazzotta

We construct novel conformal sigma models in three dimensions. Nonlinear sigma models in three dimensions are nonrenormalizable in perturbation theory. We use Wilsonian renormalization group equation method to find the fixed points.…

High Energy Physics - Theory · Physics 2009-11-13 Takeshi Higashi , Kiyoshi Higashijima , Etsuko Itou

Substantial effort has been devoted in determining the ideal proxy for quantifying the morphology of the hot intracluster medium in clusters of galaxies. These proxies, based on X-ray emission, typically require expensive, high-quality…

Astrophysics of Galaxies · Physics 2018-01-31 Ian D. Roberts , Laura C. Parker , Julie Hlavacek-Larrondo