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We present an explicit exact solution of Einstein's equations for an inhomogeneous dust universe with cylindrical symmetry. The spacetime is extremely simple but nonetheless it has new surprising features. The universe is ``closed'' in the…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Jose M. M. Senovilla , Raul Vera

These lectures deal with our current knowledge of the matter distribution in the universe, focusing on how this is studied via the large-scale structure seen in galaxy surveys. We first assemble the necessary basics needed to understand the…

Astrophysics · Physics 2007-05-23 J. A. Peacock

Using the HST archive WFPC2 observations and rotation curves measeured by Vogt et al. (1996), we constructed self-consistent light and mass distribution models for three disk galaxies at redshifts z = 0.15, 0.90 and 0.99. The models consist…

Astrophysics · Physics 2008-11-26 Antti Tamm , Peeter Tenjes

Extinction by intergalactic gray dust introduces a magnitude redshift dependent offset in the standard-candle relation of SN Ia. This leads to overestimated luminosity distances compared to a dust-free universe. Quantifying the amplitude of…

Astrophysics · Physics 2008-11-26 Pier Stefano Corasaniti

The effect of curvature on the results of fractal analyses of the galaxy distribution is investigated. We show that, if the universe satisfies the criteria of a wide class of parabolic homogeneous models, the observers measuring the fractal…

Astrophysics · Physics 2009-10-31 Marie-Noëlle Célérier , Reuben Thieberger

We present and discuss the results of new multiple-scattering radiative transfer calculations for three representative types of galactic environments, filled with either homogeneous or two-phase clumpy dust distributions. Extinction and…

Astrophysics · Physics 2009-10-05 Adolf N. Witt , Karl D. Gordon

Our observations of the Universe are fundamentally anisotropic, with data from galaxies separated transverse to the line of sight coming from the same epoch while that from galaxies separated parallel to the line of sight coming from…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-26 Eric V. Linder , MinJi Oh , Teppei Okumura , Cristiano G. Sabiu , Yong-Seon Song

A mildly inhomogeneous universe with a cosmological constant may look like it contains evolving dark energy. We show that could be the case by modelling the inhomogeneities and their effects in three different ways: as clumped matter…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-29 Yonadav Barry Ginat , Pedro G. Ferreira

The presence of dark energy in the Universe is inferred directly from the accelerated expansion of the Universe, and indirectly, from measurements of cosmic microwave background (CMB) anisotropy. Dark energy contributes about 2/3 of the…

Astrophysics · Physics 2009-11-06 Dragan Huterer , Michael S. Turner

The BOSS quasar sample is used to study cosmic homogeneity with a 3D survey in the redshift range $2.2<z<2.8$. We measure the count-in-sphere, $N(<\! r)$, i.e. the average number of objects around a given object, and its logarithmic…

Exotic dark matter together with the vacuum energy or cosmological constant seem to dominate in the Universe. An even higher density of such matter seems to be gravitationally trapped in the Galaxy. Thus its direct detection is central to…

High Energy Physics - Phenomenology · Physics 2014-11-17 J. D. Vergados

Distance duality relation (DDR) marks a fundamental difference between expanding and nonexpanding Universes, as an expanding metric causes angular diameter distance smaller than luminosity distance by an extra factor of $(1+z)$. Here we…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-29 Pengfei Li

The presence of inhomogeneities modifies the cosmic distances through the gravitational lensing effect, and, indirectly, must affect the main cosmological tests. Assuming that the dark energy is a smooth component, the simplest way to…

Astrophysics · Physics 2008-11-26 R. C. Santos , J. V. Cunha , J. A. S. Lima

The Universe on scales $10-100~h^{-1}$ Mpc is dominated by a cosmic web of voids, filaments, sheets and knots of galaxy clusters. These structures participate differently in the global expansion of the Universe: from non-expanding clusters…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-21 Krzysztof Bolejko , M. Ahsan Nazer , David L. Wiltshire

This paper studies the effect of the distance choice in radial (non-average) statistical tools used for fractal characterization of galaxy distribution. After reviewing the basics of measuring distances of cosmological sources, various…

Astrophysics · Physics 2014-10-13 Marcelo B. Ribeiro

Estimating the temperature and mass of dust in high-$z$ galaxies is essential for discussions of the origin of dust in the early Universe. However, this suffers from limited sampling of the infrared spectral-energy distribution. Here we…

Astrophysics of Galaxies · Physics 2020-06-03 Akio K. Inoue , Takuya Hashimoto , Hiroki Chihara , Chiyoe Koike

We compute the cosmic star formation rate (SFR) and the rest-frame comoving luminosity density in various pass-bands as a function of redshift using large-scale \Lambda-CDM hydrodynamical simulations with the aim of understanding their…

Astrophysics · Physics 2009-10-31 Kentaro Nagamine , Renyue Cen , Jeremiah P. Ostriker

We show that the difference between the theoretically expected and measured by WMAP amplitude of the quadrupole fluctuations of CMB can be related to the impact of the anisotropic curvature of the homogeneous universe dominated by the dark…

Astrophysics · Physics 2008-11-26 M. Demiański , A. G. Doroshkevich

The universe, with large-scale homogeneity, is locally inhomogeneous, clustering into stars, galaxies and larger structures. Such property is described by the smoothness parameter $\alpha$ which is defined as the proportion of matter in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Hao-Ran Yu , Tian Lan , Hao-Yi Wan , Tong-Jie Zhang , Bao-Quan Wang

We assess the dominant low-redshift anisotropic signatures in the distance-redshift relation and redshift drift signals. We adopt general-relativistic irrotational dust models allowing for gravitational radiation -- the `quiet universe…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-06 Asta Heinesen , Hayley J. Macpherson