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We perform a joint likelihood analysis of the power spectra of the 2dF Galaxy Redshift Survey (2dFGRS) and the cosmic microwave background (CMB) anisotropies under the assumptions that the initial fluctuations were adiabatic, Gaussian and…

The cosmic microwave background temperature is a cornerstone astrophysical observable. Its present value is tightly constrained, but its redshift dependence, which can now be determined until redshift $z\sim6.34$, is also an important probe…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-23 L. Gelo , C. J. A. P. Martins , N. Quevedo , A. M. M. Vieira

The presence of dark energy at high redshift influences both the cosmic sound horizon and the distance to last scattering of the cosmic microwave background. We demonstrate that through the degeneracy in their ratio, early dark energy can…

Astrophysics · Physics 2009-06-23 Eric V. Linder , Georg Robbers

Using the covariant formalism developed in a companion paper (paper I), we derive observational constraint on the Brans-Dicke model in a flat FLRW universe with cosmological constant and cold dark matter. The CMB observations we use include…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-18 Fengquan Wu , Xuelei Chen

The so-called shift parameter is related to the position of the first acoustic peak in the power spectrum anisotropies of the cosmic microwave background (CMB) anisotropies. It is an often used quantity in simple tests of dark energy…

Astrophysics · Physics 2009-11-13 Oystein Elgaroy , Tuomas Multamaki

Experimental evidence over a number of recent years has shown the density parameter of the universe omega converging to the critical value of 1, which defines a flat, Euclidean universe. No such calculations have defined a critical value…

General Physics · Physics 2013-06-20 Peter Rowlands

We cross-correlate the Cosmic Microwave Background (CMB) temperature anisotropies observed by the Wilkinson Microwave Anisotropy Probe (WMAP) with the projected distribution of extended sources in the Two Micron All Sky Survey (2MASS). By…

Astrophysics · Physics 2009-08-29 Niayesh Afshordi , Yeong-Shang Loh , Michael A. Strauss

We examine interactions between dark matter and dark energy in light of the latest cosmological observations, focusing on a specific model with coupling proportional to the dark energy density. Our data includes Cosmic Microwave Background…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-10 Eleonora Di Valentino , Alessandro Melchiorri , Olga Mena , Sunny Vagnozzi

Interacting dark energy models have been suggested as alternatives to the standard cosmological model, $\Lambda$CDM. We focus on a phenomenologically interesting class of dark scattering models that is characterised by pure momentum…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-08 Maria Tsedrik , Chiara Moretti , Pedro Carrilho , Federico Rizzo , Alkistis Pourtsidou

A new method for estimating the power spectrum $C_l$ from cosmic microwave background (CMB) maps was recently presented by the author and applied to the 2 year COBE data. It was found that the spectral resolution $\Delta l$ for COBE could…

Astrophysics · Physics 2016-08-30 Max Tegmark

We calculate the large-angle cross-correlation between the cosmic-microwave-background (CMB) temperature and the x-ray-background (XRB) intensity expected in an open Universe with cold dark matter (CDM) and a nearly scale-invariant spectrum…

Astrophysics · Physics 2009-10-30 Ali Kinkhabwala , Marc Kamionkowski

Imagine a scenario in which the dark energy forms via the condensation of dark matter at some low redshift. The Compton wavelength therefore changes from small to very large at the transition, unlike quintessence or metamorphosis. We study…

Astrophysics · Physics 2009-11-07 Bruce A. Bassett , Martin Kunz , David Parkinson , Carlo Ungarelli

A correlation between the surface density of foreground galaxies tracing the Large Scale Structure and the position of distant galaxies and quasars is expected from the magnification bias effect (Canizares 1981). We show that this…

Astrophysics · Physics 2016-08-30 N. Benitez , J. L. Sanz

Angular power spectrum of the cosmic microwave background (CMB) temperature anisotropies is one of the most important on characteristics of the Universe such as its geometry and total density. Using flat sky approximation and Fourier…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Lung-Yih Chiang , Fei-Fan Chen

Dark photons that kinetically mix with the Standard Model photon give rise to new spectral anisotropies (patchy dark screening) in the cosmic microwave background (CMB) due to conversion of photons to dark photons within large-scale…

High Energy Physics - Phenomenology · Physics 2024-06-06 Fiona McCarthy , Dalila Pirvu , J. Colin Hill , Junwu Huang , Matthew C. Johnson , Keir K. Rogers

Cosmic microwave background (CMB) temperature anisotropies have and will continue to revolutionize our understanding of cosmology. The recent discovery of the previously predicted acoustic peaks in the power spectrum has established a…

Astrophysics · Physics 2011-07-19 Wayne Hu , Scott Dodelson

We study the performance of the spatially-flat dynamical dark energy (DE) $w_0w_a$CDM parameterization, with redshift-dependent DE fluid equation of state parameter $w(z) = w_0 + w_a z/(1+z)$, with and without a varying CMB lensing…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-15 Chan-Gyung Park , Javier de Cruz Perez , Bharat Ratra

We demonstrate that the aperture mass as a measure for cosmic shear closely approximates (to better than ~5%) the scaled and shifted power spectrum of the projected mass density. This cosmological weak-lensing information can thus be used…

Astrophysics · Physics 2007-05-23 Matthias Bartelmann , Peter Schneider

We compare the latest observations of Cosmic Microwave Background (CMB) Anisotropies with the theoretical predictions of the standard scenario of structure formation. Assuming a primordial power spectrum of adiabatic perturbations we found…

Astrophysics · Physics 2009-11-07 Alessandro Melchiorri , Carolina Odman

We calculate the cosmic microwave background (CMB) anisotropy spectrum in models with millicharged particles of electric charge q\sim 10^{-6}-10^{-1} in units of electron charge. We find that a large region of the parameter space for the…

High Energy Physics - Phenomenology · Physics 2009-11-10 S. L. Dubovsky , D. S. Gorbunov , G. I. Rubtsov