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A new method arising from a gauge-theoretic approach to general relativity is applied to the formation of clusters in an expanding universe. The three cosmological models (Omega_0=1, Omega_Lambda=0), (Omega_0=0.3, Omega_Lambda=0.7),…

Astrophysics · Physics 2015-06-24 Y. Dabrowski , M. J. Hall , I. L. Sawicki , A. N. Lasenby

A new method is proposed for modelling spherically symmetric inhomogeneities in the Universe. The inhomogeneities have finite size and are compensated, so they do not exert any measurable gravitational force beyond their boundary. The…

Astrophysics · Physics 2009-10-31 A. N. Lasenby , C. J. L. Doran , M. P. Hobson , Y. Dabrowski , A. D. Challinor

A new method for modelling spherically symmetric inhomogeneities is applied to the formation of clusters in an expanding Universe. We impose simple initial velocity and density perturbations of finite extent and we investigate the…

Astrophysics · Physics 2009-10-31 Y. Dabrowski , M. P. Hobson , A. N. Lasenby , C. J. L. Doran

The power spectrum of temperature anisotropies induced by hot intracluster gas on the cosmic background radiation is calculated. For low multipoles it remains constant while at multipoles above $l>2000$ it is exponentially damped. The shape…

Astrophysics · Physics 2009-10-31 F. Atrio Barandela , J. P. Muecket

We present a new method of constraining the mass and velocity anisotropy profiles of galaxy clusters from kinematic data. The method is based on a model of the phase space density which allows the anisotropy to vary with radius between two…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Radoslaw Wojtak , Ewa L. Lokas , Gary A. Mamon , Stefan Gottloeber

We use numerical simulations to calculate the cosmic microwave background anisotropy induced by the evolution of a global texture field, with special emphasis on individual textures. Both spherically symmetric and general configurations are…

Galaxy clusters will distort the pattern of temperature anisotropies in the microwave background via gravitational lensing. We create lensed microwave background maps using clusters drawn from numerical cosmological simulations. A…

Astrophysics · Physics 2009-11-10 Gilbert P. Holder , Arthur Kosowsky

Models in which a large fraction of the Galactic dark matter takes the form of cold gas clouds imply that there is thermal microwave emission from the Galactic dark halo. Such models can therefore be directly constrained by data on the…

Astrophysics · Physics 2007-05-23 Mark Walker , Michiko Ohishi , Masaki Mori

The Tolman-Bondi solution of the Einstein equations is used in order to model the time evolution of the void observed in Bo\"otes. The present density contrast of the central region ($\sim -0.75$) and its radius ($\sim 30h^{-1} \ Mpc$) are…

Astrophysics · Physics 2016-08-15 M. J. Fullana , J. V. Arnau , D. Sáez

We present cosmological simulations of galaxy clusters, with focus on the cluster outskirts. We show that large-scale cosmic accretion and mergers produce significant internal gas motions and inhomogeneous gas distribution ("clumpiness") in…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-10 Daisuke Nagai

The theoretical basis for the prediction of anisotropies in the cosmic microwave background is very well developed. Very low amplitude density and temperature perturbations produce small gravitational effects, leading to an anisotropy that…

Astrophysics · Physics 2007-05-23 E. L. Wright

The standard cosmological model, $\Lambda$CDM, assumes isotropy on large cosmic scales. However, recent studies using galaxy cluster scaling relations have reported an apparent $H_0$ anisotropy at $5.4\sigma$ that could be attributed to…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-29 Yujie He , Konstantinos Migkas , Joop Schaye , Joey Braspenning , Matthieu Schaller

In order to assess the potential of future microwave anisotropy space experiments for detecting clusters by their Sunyaev-Zeldovich (SZ) thermal effect, we have simulated maps of the large scale distribution of their Compton parameter $y$…

Astrophysics · Physics 2007-05-23 N. Aghanim , A. De Luca , F. R. Bouchet , G. Gispert , J. L. Puget

New calculations of the Galactic contamination over microwave background radiation anisotropies are carried out. On one hand, when a frequency-dependent contrast of molecular clouds with respect to the Galactic background of the diffuse…

Astrophysics · Physics 2011-05-23 M. Lopez-Corredoira

Scaling relations of galaxy clusters are a powerful probe of cosmic isotropy in the late Universe. Owing to their strong cosmological dependence, galaxy cluster scaling relations can obtain tight constraints on the spatial variation of…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-05 Konstantinos Migkas

The major contribution to the anisotropy of the temperature of the Cosmic Microwave Background (CMB) radiation is believed to come from the interaction of linear density perturbations with the radiation previous to the decoupling time.…

Astrophysics · Physics 2015-06-24 Enrique Martinez-Gonzalez

We present an analysis of the cosmological evolution of matter sources with small anisotropic pressures. This includes electric and magnetic fields, collisionless relativistic particles, gravitons, antisymmetric axion fields in low-energy…

General Relativity and Quantum Cosmology · Physics 2009-10-30 John D. Barrow

In this paper we examine how well galaxies and intra-cluster gas trace the gravitational potential of clusters. Utilizing mass profiles derived from gravitational lensing and X-ray observations, coupled with measured galaxy velocities, we…

Aside from primordial gravitational instability of the cosmological fluid, various mechanisms have been proposed to generate large-scale structure at relatively late times, including, e.g., ``late-time'' cosmological phase transitions. In…

Astrophysics · Physics 2009-10-22 Andrew H. Jaffe , Albert Stebbins , Joshua A. Frieman

We investigate the global texture model of structure formation in cosmogonies with non-zero cosmological constant for different values of the Hubble parameter. We find that the absence of significant acoustic peaks and little power on large…

Astrophysics · Physics 2009-10-31 Ruth Durrer , Martin Kunz , Alessandro Melchiorri
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