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Related papers: Constraints on a Bianchi type I spacetime extensio…

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A unification of dark matter and dark energy in terms of a logotropic perfect dark fluid has recently been proposed, where deviations with respect to the standard $\Lambda {\rm CDM}$ model are dependent on a single parameter $B$. In this…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-24 V. M. C. Ferreira , P. P. Avelino

We present a measurement of the angular power spectrum of the cosmic microwave background (CMB) using data from the South Pole Telescope (SPT). The data consist of 790 square degrees of sky observed at 150 GHz during 2008 and 2009. Here we…

In the current study, we present the observational data constraints on the parameters space for an anisotropic cosmological model of Bianchi I type spacetime in general relativity (GR). For the analysis, we consider observational datasets…

General Relativity and Quantum Cosmology · Physics 2025-07-31 Vinod Kumar Bhardwaj , Manish Kalra , Priyanka Garg , Saibal Ray

We set new constraints on a seven-dimensional space of cosmological parameters within the class of inflationary adiabatic models. We use the angular power spectrum of the cosmic microwave background measured over a wide range of \ell in the…

We present new Big Bang Nucleosynthesis (BBN) limits on the cosmic expansion rate or relativistic energy density, quantified via the number $N_\nu$ of equivalent neutrino species. We use the latest light element observations, neutron mean…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-01 Tsung-Han Yeh , Jessie Shelton , Keith A. Olive , Brian D. Fields

We use the Cosmic Microwave Background (CMB) anisotropy data from Planck to constrain the spatial fluctuations of the fine-structure constant \alpha. Through Thompson scattering of CMB photons, spatial anisotropies of \alpha lead to…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-07 Jon O'Bryan , Joseph Smidt , Francesco De Bernardis , Asantha Cooray

We present the results of analysis of constraints on cosmological parameters from cosmic microwave background (CMB) alone and in combination with galaxy cluster baryon fraction assuming inflation--generated adiabatic scalar fluctuations.…

Astrophysics · Physics 2009-11-06 M. Douspis , A. Blanchard , R. Sadat , J. G. Bartlett , M. Le Dour

This is a course on cosmic microwave background (CMB) anisotropies in the standard cosmological model, designed for beginning graduate students and advanced undergraduates. ``Standard cosmological model'' in this context means a Universe…

Astrophysics · Physics 2009-10-31 James G. Bartlett

Despite the ability of the cosmological concordance model ($\Lambda$CDM) to describe the cosmological observations exceedingly well, power law expansion of the Universe scale radius, $R(t)\propto t^n$, has been proposed as an alternative…

We explore extensions to the $\Lambda$CDM cosmology using measurements of the cosmic microwave background (CMB) from the recent SPT-SZ survey, along with data from WMAP7 and measurements of $H_0$ and BAO. We check for consistency within…

We describe constraints on a ``standard'' 8 parameter open cold dark matter (CDM) model from the most recent CMB and SN1a data. Our parameters are the densities of CDM, baryons, vacuum energy and curvature, the reionization optical depth,…

Astrophysics · Physics 2009-10-30 Max Tegmark

Following the recent measurement of the acoustic peak by the BOOMERanG and MAXIMA experiments in the CMB anisotropy angular power spectrum, many analyses have found that the geometry of the Universe is very close to flat, but slightly…

Astrophysics · Physics 2009-10-31 Alessandro Melchiorri , Louise M. Griffiths

We constrain the thermal evolution of the universe with a decaying cosmological term by using the method of the analysis for the Wilkinson Microwave Anisotropy Probe (WMAP) observation data. The cosmological term is assumed to be a function…

Astrophysics · Physics 2008-11-26 Riou Nakamura , Masa-aki Hashimoto , Kiyotomo Ichiki

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

We perform a general test of the $\Lambda{\rm CDM}$ and $w {\rm CDM}$ cosmological models by comparing constraints on the geometry of the expansion history to those on the growth of structure. Specifically, we split the total matter energy…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-25 Uendert Andrade , Dhayaa Anbajagane , Rodrigo von Marttens , Dragan Huterer , Jailson Alcaniz

We consider structure formation and CMB anisotropies in a closed universe, both with and without a cosmological constant. The CMB angular power spectrum and the matter transfer function are presented, along with a discussion of their…

Astrophysics · Physics 2009-08-18 Martin White , Douglas Scott

We explore the large angular scale temperature anisotropies in the cosmic microwave background (CMB) due to homogeneous local dust-filled voids in a flat Friedmann-Robertson-Walker universe with a cosmological constant. In comparison with…

Astrophysics · Physics 2008-11-26 Kaiki Taro Inoue , Joseph Silk

This document describes the Millimeter Anisotropy eXperiment IMaging Array (MAXIMA), a balloon-borne experiment measuring the temperature anisotropy of the Cosmic Microwave Background (CMB) on angular scales of 10 arcminutes to 5 degrees.…

Astrophysics · Physics 2011-11-09 Bahman Rabii

In this study, we have explored a scalar field cosmological model in the axially symmetric Bianchi type-I universe. In this study, our aim is to constrain the scalar field dark energy model in an anisotropic background. For this purpose,…

General Relativity and Quantum Cosmology · Physics 2025-11-19 Vinod Kumar Bhardwaj , Anil Kumar Yadav

We present new cosmological constraints in a set of motivated extensions of the $\Lambda$CDM model using the polarization and gravitational lensing measurements from the South Pole Telescope and the Planck CMB temperature observations at…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-14 Anton Chudaykin , Dmitry Gorbunov , Nikita Nedelko