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We investigate whether non-adiabatic perturbations from inflation could produce an asymmetric distribution of temperature anisotropies on large angular scales in the cosmic microwave background (CMB). We use a generalised non-linear $\delta…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Hooshyar Assadullahi , Hassan Firouzjahi , Mohammad Hossein Namjoo , David Wands

We consider the issue of hemispherical power asymmetry in the three-year WMAP data, adopting a previously introduced modulation framework. Computing both frequentist probabilities and Bayesian evidences, we find that the model consisiting…

Astrophysics · Physics 2009-11-13 H. K. Eriksen , A. J. Banday , K. M. Gorski , F. K. Hansen , P. B. Lilje

Much recent work on the cosmic microwave background (CMB) has focussed on the angular power spectrum of temperature anisotropies and particularly on the recovery of cosmological parameters from acoustic peaks in the power spectrum. However,…

Astrophysics · Physics 2007-05-23 Marc Kamionkowski

We discuss full-sky convolution of the instrumental beam with the CMB sky signal in CMB single-dish and interferometry experiments, using the method (Challinor et al. 2000) that the measured temperature and polarization anisotropies are…

Astrophysics · Physics 2009-11-10 Kin-Wang Ng

Low multipoles ($l$) in cosmic microwave background (CMB) temperature anisotropies have shown some `peculiarities' when examined since the release of the full sky CMB maps, using a variety of tests. In this paper, we concern ourselves with…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-01 Pavan Kumar Aluri , Sanjeet Kumar Patel

We present an updated data-analysis comparison of the most recent observations of the Cosmic Microwave Background temperature anisotropies and polarization angular power spectra released by four different experiments: the Planck satellite…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-15 Eleonora Di Valentino , William Giarè , Alessandro Melchiorri , Joseph Silk

We evaluate the degradation of the accuracy of the component separation between the cosmic microwave background (CMB) and foreground components caused by neglect of absorption of the monopole component of the CMB by the galactic…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-03 Masashi Nashimoto , Makoto Hattori , Yuji Chinone

We present the first ever calculation of cosmic microwave background CMB anisotropy power spectra from semilocal cosmic strings, obtained via simulations of a classical field theory. Semilocal strings are a type of non-topological defect…

Astrophysics · Physics 2009-06-23 Jon Urrestilla , Neil Bevis , Mark Hindmarsh , Martin Kunz , Andrew R. Liddle

Search for the statistical anisotropy in the CMB data is a powerful tool for constraining models of the early Universe. In this paper we focus on the recently proposed cosmological scenario with conformal rolling. We consider two…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 S. R. Ramazanov , G. I. Rubtsov

A compact overview of the status of CMB anisotropy results and their cosmological interpretation. Section headings: Introduction; CMB Spectrum; Description of CMB Anisotropies; Cosmological Parameters; Physics of Anisotropies; Current…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-09 Douglas Scott , George F. Smoot

Precise measurements of the Cosmic Microwave Background (CMB) anisotropy have been one of the foremost concerns in modern cosmology as it provides valuable information on the cosmology of the universe. However, an accurate estimation of the…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-20 Fidy A. Ramamonjisoa , Subharthi Ray , Sanjit Mitra , Tarun Souradeep

Searching for the signal of primordial gravitational waves in the B-modes (BB) power spectrum is one of the key scientific aims of the cosmic microwave background (CMB) polarization experiments. However, this could be easily contaminated by…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Si-Yu Li , Jun-Qing Xia , Mingzhe Li , Hong Li , Xinmin Zhang

The scalar mode temperature fluctuations of the cosmic microwave background has been derived in a spatially closed universe from two different methods. First, by following the photon trajectory after the last scattering and then from the…

General Relativity and Quantum Cosmology · Physics 2017-09-27 Pedram Niazy , Amir H. Abbassi

The linear anisotropies in the temperature of the cosmic microwave background (CMB) radiation and its polarization provide a clean picture of fluctuations in the universe some 370 kyr after the big bang. Simple physics connects these…

Astrophysics · Physics 2007-05-23 Anthony Challinor

Anisotropies in distortions to the frequency spectrum of the cosmic microwave background (CMB) can be created through spatially varying heating processes in the early Universe. For instance, the dissipation of small-scale acoustic modes…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-25 Jens Chluba , Emanuela Dimastrogiovanni , Mustafa A. Amin , Marc Kamionkowski

We use Nambu-Goto numerical simulations to compute the cosmic microwave background (CMB) temperature anisotropies induced at arcminute angular scales by a network of cosmic strings in a Friedmann-Lemaitre-Robertson-Walker (FLRW) expanding…

The recent measurements of temperature and polarization of Cosmic Microwave Background (CMB) have improved our understanding of the Universe and are in remarkable agreement with the $\Lambda$CDM cosmological model. However, scale dependent…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-15 Suvodip Mukherjee , Tarun Souradeep

It is well known that our motion with respect to the cosmic microwave background (CMB) rest frame introduces a large dipolar CMB anisotropy, with an amplitude ~beta=v/c~10^{-3}. In addition it should lead to a small breaking of statistical…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 J. Chluba

Parity violating physics beyond the standard model of particle physics induces a rotation of the linear polarization of photons. This effect, also known as cosmological birefringence (CB), can be tested with the observations of the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 Alessandro Gruppuso , Gianmarco Maggio , Diego Molinari , Paolo Natoli

Bianchi VII_h models have been recently proposed to explain potential anomalies in the CMB anisotropy as observed by WMAP. We investigate the violation of statistical isotropy due to an embedded Bianchi VII_h templates in the CMB anisotropy…

Astrophysics · Physics 2008-11-26 Tuhin Ghosh , Amir Hajian , Tarun Souradeep