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In this paper, we study the cosmological implications of the 100 square degree Weak Lensing survey (the CFHTLS-Wide, RCS, VIRMOS-DESCART and GaBoDS surveys). We combine these weak lensing data with the cosmic microwave background (CMB)…

Astrophysics · Physics 2010-05-07 Hong Li , Jie Liu , Jun-Qing Xia , Lei Sun , Zu-Hui Fan , Charling Tao , Andre Tilquin , Xinmin Zhang

I develop a method for assessing the ability of an instrument, coupled with an observing strategy, to measure the angular power spectrum of the cosmic microwave background (CMB). It allows for efficient calculation of expected parameter…

Astrophysics · Physics 2009-10-28 Lloyd Knox

We present a Bayesian sampling algorithm called adaptive importance sampling or Population Monte Carlo (PMC), whose computational workload is easily parallelizable and thus has the potential to considerably reduce the wall-clock time…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-02 Darren Wraith , Martin Kilbinger , Karim Benabed , Olivier Cappé , Jean-François Cardoso , Gersende Fort , Simon Prunet , Christian P. Robert

We describe the Bayesian-based signal-to-noise eigenmode method for cosmological parameter estimation, show how it can be used to optimally compress large CMB anisotropy data sets to manageable sizes, and apply it to the DMR 4-year, South…

Astrophysics · Physics 2007-05-23 J. Richard Bond , Andrew H. Jaffe

In this letter, we report the observational constraints on a Bianchi type I anisotropic extension of $w$CDM model with spatial curvature from observational data including Baryon Acoustic Oscillations (BAO), Cosmic chronometers (CC), Big…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-21 Vikrant Yadav , Rajpal , Pardeep , Manish Yadav , Santosh Kumar Yadav

The standard model of cosmology, {\Lambda}CDM, is the simplest model that matches the current observations, but it relies on two hypothetical components, to wit, dark matter and dark energy. Future galaxy surveys and cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-13 Cyrille Doux , Mariana Penna-Lima , Sandro D. P. Vitenti , Julien Tréguer , Eric Aubourg , Ken Ganga

Bianchi type III (BIII) metric is an interesting anisotropic model for studying cosmic anisotropy as it has an additional exponential term multiplied to a directional scale factor. Thus, the cosmological parameters obtained for this BIII…

General Relativity and Quantum Cosmology · Physics 2025-09-03 Pranjal Sarmah , Umananda Dev Goswami

We perform a definitive analysis of Bianchi VII_h cosmologies with WMAP observations of the cosmic microwave background (CMB) temperature anisotropies. Bayesian analysis techniques are developed to study anisotropic cosmologies using…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-04 J. D. McEwen , T. Josset , S. M. Feeney , H. V. Peiris , A. N. Lasenby

In this work we perform an observational data analysis on the $f(R,T)$ gravity with the aim of constraining the parameter space of the model. Five different models are considered and the 30 point $z-H(z)$ cosmic chronometer data is used in…

General Relativity and Quantum Cosmology · Physics 2021-05-24 Prabir Rudra , Kinsuk Giri

We present a new framework for testing the isotropy of the Universe using cosmic microwave background data, building on the nested-sampling ANICOSMO code. Uniquely, we are able to constrain the scalar, vector and tensor degrees of freedom…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-08 Daniela Saadeh , Stephen M. Feeney , Andrew Pontzen , Hiranya V. Peiris , Jason D. McEwen

Recent observations suggest that there are violations of the isotropy of the universe at large scales, an important part of the cosmological principle. In this paper, we use the Cosmic Microwave Background (CMB) data to search for spatial…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-20 Shek Yeung , Ming-Chung Chu

CMB anisotropy data could put powerful constraints on theories of the evolution of our Universe. Using the observations of the large number of CMB experiments, many studies have put constraints on cosmological parameters assuming different…

Astrophysics · Physics 2015-06-24 Marian Douspis

We investigate observational constraints on cosmological parameters combining 15 measurements of the transversal BAO scale (obtained free of any fiducial cosmology) with Planck-CMB data to explore the parametric space of some cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-10 Rafael C. Nunes , Santosh K. Yadav , J. F. Jesus , Armando Bernui

In the first part of this work, I review the theoretical framework of cosmological perturbation theory necessary to understand the generation and evolution of cosmic microwave background (CMB) anisotropies. Using analytical and numerical…

Astrophysics · Physics 2009-09-29 Roberto Trotta

The study of cosmic birefringence through Cosmic Microwave Background (CMB) experiments is a key research area in cosmology and particle physics, providing a critical test for Lorentz and CPT symmetries. This paper focuses on an upcoming…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-18 Yiwei Zhong , Hongbo Cai , Si-Yu Li , Yang Liu , Mingzhe Li , Wenjuan Fang

We challenge the widely held belief that the cosmological principle is an obvious consequence of the observed isotropy of the cosmic microwave background radiation, combined with the Copernican principle. We perform a detailed analysis of a…

Astrophysics · Physics 2009-10-31 R. K. Barrett , C. A. Clarkson

We describe the calibration and data processing methods used to generate full-sky maps of the cosmic microwave background (CMB) from the first year of Wilkinson Microwave Anisotropy Probe (WMAP) observations. Detailed limits on residual…

We present a new method for calculating linear cosmic microwave background (CMB) anisotropy spectra based on integration over sources along the photon past light cone. In this approach the temperature anisotropy is written as a time…

Astrophysics · Physics 2008-11-26 Uros Seljak , Matias Zaldarriaga

We study the prospects for extracting cosmological and astrophysical parameters from the low radio frequency 21-cm background due to the spin-flip transition of neutral Hydrogen during and prior to the reionization of the Universe. We make…

Astrophysics · Physics 2009-11-11 Mario G. Santos , Asantha Cooray

We present limits to anisotropies in the cosmic microwave background radiation (CMB) at angular scales of a few arcminutes. The observations were made at a frequency of 142 GHz using a 6-element bolometer array (the Sunyaev-Zel'dovich…