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Recent observational analyses have suggested possible evidence of hemisphere asymmetry in cosmological datasets. Parameterizations of this kind place observers in a privileged position-specifically on the plane that divides the two…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-16 Xin Wang , Zhiqi Huang

We investigate the effect of dark energy on the limits on the shear anisotropy in spatially homogeneous Bianchi cosmological models obtained from measurements of the temperature anisotropies in the cosmic microwave background. We shall…

Astrophysics · Physics 2010-05-12 A. A. Coley , W. C. Lim

We use the physically-consistent tilted spatially-flat and untilted non-flat $\Lambda$CDM inflation models to constrain cosmological parameter values with the Planck 2015 cosmic microwave background (CMB) anisotropy data and recent Type Ia…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-19 Chan-Gyung Park , Bharat Ratra

We present a formalism for analyzing interferometric observations of Cosmic Microwave Background (CMB) anisotropy and polarization data. The formalism is based upon the ell-space expansion of the angular power spectrum favoured in recent…

Astrophysics · Physics 2009-08-18 Martin White , John E. Carlstrom , Mark Dragovan , William L. Holzapfel

It is well known that flat FRW metric is a special case of Bianchi type I spacetime. In this paper, we use 38 Hubble parameter, $H(z)$, measurements at intermediate redshifts $0.07\leq z\leq 2.36$ and its joint combination with the latest…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-21 Hassan Amirhashchi

We use current cosmic microwave background data to constrain cosmological parameters. The results are presented as confidence regions in the ($\Omega$--$H_o$) -- plane for both open and flat geometries, and are based on a $\chi^2$…

Astrophysics · Physics 2007-05-23 J. G. Bartlett , A. Blanchard , M. Le Dour , M. Douspis , D. Barbosa

We use updated Type Ia Pantheon+ supernova, baryon acoustic oscillation, and Hubble parameter (now also accounting for correlations) data, as well as new reverberation-measured C IV quasar data, and quasar angular size, H II starburst…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-19 Shulei Cao , Bharat Ratra

We use data from the ARGO cosmic microwave background (CMB) anisotropy experiment to constrain cosmogonies. We account for the ARGO beamwidth and calibration uncertainties, and marginalize over the offset removed from the data. Our derived…

We report a measurement of anisotropy in the cosmic microwave background radiation (CMBR) on 7-22 arcminute scales. Observations of 36 fields near the North Celestial Pole (NCP) were made at 31.7 and 14.5 GHz, using the 5.5-meter and…

Astrophysics · Physics 2007-05-23 E. M. Leitch , A. C. S. Readhead , T. J. Pearson , S. T. Myers , S. Gulkis , C. R. Lawrence

We test anisotropic dark energy models with the 7-year WMAP temperature observations data. In the presence of imperfect sources, due to large-scale gradients or anisotropies in the dark energy field, the CMB sky will be distorted…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-08 Magnus J. Axelsson , Frode K. Hansen , Tomi Koivisto , David F. Mota

According to standard cosmology, the universe is homogeneous and isotropic at large scales. However, some anisotropies can be observed at the local scale in the universe through various ways. Here we have studied the Bianchi type I model…

General Relativity and Quantum Cosmology · Physics 2022-09-12 Pranjal Sarmah , Umananda Dev Goswami

Cosmological Boltzmann codes are often used by researchers for calculating the CMB angular power spectra from different theoretical models, for cosmological parameter estimation, etc. Therefore, the accuracy of a Boltzmann code is of utmost…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-09 Santanu Das , Anh Phan

In this paper, we revisit the Cardassian model in which the radiation energy component is included. It is important for early epoch when the radiation cannot be neglected because the equation of state (EoS) of the effective dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-05 Lixin Xu

The cosmic microwave background (CMB) anisotropy possesses the remarkable property that its power is strongly suppressed on large angular scales. This observational fact can naturally be explained by cosmological models with a non-trivial…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Ralf Aurich , Sven Lustig

The CMB anisotropy depends sensitively upon the slope and amplitude of primordial density and gravitational wave fluctuations, the baryon density, the Hubble constant, the cosmological constant, the ionization history, {\it etc.} We report…

Astrophysics · Physics 2009-09-25 J. Richard Bond , Richard L. Davis , Paul J. Steinhardt

Wide area cosmological surveys enable investigation of whether dark energy properties are the same in different directions on the sky. Cosmic microwave background observations strongly restrict any dynamical effects from anisotropy, in an…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-05 Stephen A. Appleby , Eric V. Linder

The observational data on the large scale structure (LSS) of the Universe are used to determine cosmological parameters within the class of adiabatic inflationary models. We show that a mixed dark matter model with cosmological constant…

Astrophysics · Physics 2007-05-23 B. Novosyadlyj , R. Durrer , S. Apunevych

The presence of astrophysical emissions between the last scattering surface and our vantage point requires us to apply a foreground mask on CMB sky map, leading to large cut around the Galactic equator and numerous holes. Since many CMB…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-17 Jaiseung Kim , Pavel Naselsky , Nazzareno Mandolesi

The recent data from the Boomerang and MAXIMA-1 balloon flights have marked the beginning of the precision era of Cosmic Microwave Background anisotropy (CMB) measurements. We investigate the observational constraints from the current CMB…

Astrophysics · Physics 2009-10-31 William H. Kinney , Alessandro Melchiorri , Antonio Riotto

We discuss the construction of cosmological models within the framework of Macroscopic Gravity (MG), which is a theory that models the effects of averaging the geometry of space-time on large scales. We find new exact spatially homogeneous…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Timothy Clifton , Alan Coley , Robert van den Hoogen