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We discuss three recent developments in the calculation of CMB anisotropies. First, we consider relativistic corrections to the Sunyaev-Zel'dovich effect. By extending the Kompaneets equation to the relativistic domain we are able to derive…

天体物理学 · 物理学 2009-09-25 A. D. Challinor , A. N. Lasenby

We propose a new method for extracting the non-Gaussian signatures on the isotemperature statistics in the cosmic microwave background (CMB) sky, which is induced by the gravitational lensing due to the intervening large-scale structure of…

天体物理学 · 物理学 2009-11-06 Masahiro Takada

We propose fast, exact and efficient algorithms for the convolution of two arbitrary functions on the sphere which speed up computations by a factor \order{\sqrt{N}} compared to present methods where $N$ is the number of pixels. No…

天体物理学 · 物理学 2009-10-31 Benjamin D. Wandelt , Krzysztof M. Gorski

We develop a new, efficient code for solving the second-order Einstein-Boltzmann equations, and use it to estimate the intrinsic CMB non-Gaussianity arising from the non-linear evolution of density perturbations. The full calculation…

宇宙学与河外天体物理 · 物理学 2015-06-12 Guido W. Pettinari , Christian Fidler , Robert Crittenden , Kazuya Koyama , David Wands

A new method is proposed for modelling spherically symmetric inhomogeneities in the Universe. The inhomogeneities have finite size and are compensated, so they do not exert any measurable gravitational force beyond their boundary. The…

天体物理学 · 物理学 2009-10-31 A. N. Lasenby , C. J. L. Doran , M. P. Hobson , Y. Dabrowski , A. D. Challinor

Angular power spectra of temperature anisotropies and polarization of the cosmic microwave background (CMB) as well as the linear matter power spectra are calculated for models with three light neutrinos with non-thermal phase-space…

宇宙学与河外天体物理 · 物理学 2021-11-24 Kerstin E. Kunze

The fluctuations of the cosmic microwave background (CMB) are investigated for a hyperbolic universe with finite volume. Four-component models with radiation, matter, vacuum energy, and an extra spatially constant dark energy X-component…

天体物理学 · 物理学 2015-06-24 R. Aurich , F. Steiner

Spectral distortions and anisotropies of the CMB provide independent and complementary probes to study energy injection processes in the early universe. Here we discuss the synergy between these observables, and show the promising future of…

宇宙学与河外天体物理 · 物理学 2020-03-04 Matteo Lucca , Nils Schöneberg , Deanna C. Hooper , Julien Lesgourgues , Jens Chluba

We describe a new numerical algorithm to obtain high-resolution simulated maps of the Cosmic Microwave Background (CMB), for a broad class of non-Gaussian models. The kind of non-Gaussianity we account for is based on the simple idea that…

天体物理学 · 物理学 2009-11-07 Michele Liguori , Sabino Matarrese , Lauro Moscardini

Precise measurement of the angular power spectrum of the Cosmic Microwave Background (CMB) temperature and polarization anisotropy can tightly constrain many cosmological models and parameters. However, accurate measurements can only be…

宇宙学与河外天体物理 · 物理学 2015-03-17 S. Mitra , G. Rocha , K. M. Górski , K. M. Huffenberger , H. K. Eriksen , M. A. J. Ashdown , C. R. Lawrence

In this letter we will show that, contrary to what is widely believed, an almost isotropic cosmic microwave background (CMB) temperature does not imply that the universe is ``close to a Friedmann-Lemaitre universe''. There are two important…

天体物理学 · 物理学 2009-10-31 U. S. Nilsson , C. Uggla , J. Wainwright , W. C. Lim

Fast and accurate computations of the power spectrum of cosmic microwave background fluctuations are essential for comparing current and upcoming data sets with the large parameter space of viable cosmological models. The most efficient…

天体物理学 · 物理学 2007-05-23 Arthur Kosowsky

Measurements of the cosmic microwave background (CMB) allow high precision observation of the cosmic plasma at redshift z~1100. After the success of the NASA satellite COBE, that in 1992 provided the first detection of the CMB anisotropy,…

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…

天体物理学 · 物理学 2008-11-26 Uros Seljak , Matias Zaldarriaga

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…

宇宙学与河外天体物理 · 物理学 2017-01-25 Jens Chluba , Emanuela Dimastrogiovanni , Mustafa A. Amin , Marc Kamionkowski

We study the cosmic microwave background (CMB) anisotropy due to spherically symmetric nonlinear structures in flat universes with dust and a cosmological constant. By modeling a time-evolving spherical compensated void/lump by…

天体物理学 · 物理学 2009-02-20 Nobuyuki Sakai , Kaiki Taro Inoue

We present methods to compute maps of CMB fluctuations from high resolution cosmic string networks using a full Boltzmann code, on both large and small angular scales. The accuracy and efficency of these methods are discussed.

天体物理学 · 物理学 2009-11-07 M. Landriau , E. P. S. Shellard

Recent reports of stochastic gravitational wave background from four independent pulsar-timing-array collaborations have renewed the interest in the cosmological gravitational wave background (CGWB), which is expected to open a new window…

宇宙学与河外天体物理 · 物理学 2025-01-09 Rong-Gen Cai , Shao-Jiang Wang , Zi-Yan Yuwen , Xiang-Xi Zeng

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…

宇宙学与河外天体物理 · 物理学 2025-04-18 Yiwei Zhong , Hongbo Cai , Si-Yu Li , Yang Liu , Mingzhe Li , Wenjuan Fang

Homogeneous and nearly-isotropic cosmological models are natural extensions of standard Friedmann cosmologies. Constraining their features is crucial, as any detection of their properties would impact our understanding of inflation and the…

宇宙学与河外天体物理 · 物理学 2026-02-16 João G. Vicente , Thiago S. Pereira , Cyril Pitrou