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Cosmic microwave background (CMB) anisotropies and density fluctuations are calculated for flat cold dark matter (CDM) models with a wide range of parameters, i.e., $\Omega_0, h$ and $\Omega_B$ for both standard recombination and various…

Astrophysics · Physics 2009-10-22 Naoshi Sugiyama

Significant evidence for a stochastic gravitational-wave background has recently been reported by several Pulsar Timing Array observations. These studies have shown that, in addition to astrophysical explanations based on supermassive black…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-13 Ran Ding , Chi Tian

CMB anisotropies are modified by the weak lensing effect of intervening large scale structures on the photon path from the last scattering surface to the observer. This has to be accounted for when observational data of sensitive…

Astrophysics · Physics 2010-10-27 Jonathan Rocher , Karim Benabed , Francois Bouchet

We calculate the full second-order radiation transfer function for Cosmic Microwave Background anisotropies on large angular scales in a flat universe filled with matter and cosmological constant. It includes (i) the second-order…

Astrophysics · Physics 2009-11-13 N. Bartolo , S. Matarrese , A. Riotto

We compute the non-Gaussian corrections to the energy density and anisotropies of gravitational waves induced during the radiation era after an ultra-slow-roll phase of inflation by using a diagrammatic approach, and present the…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-15 Juan Álvarez Ruiz , Julián Rey

We use the Cosmic Microwave Background Anisotropies (CMBA) power spectra to constrain the cosmological variation of gravitational constant G. It is found that the sensitivity of CMBA to the variation of G is enhanced when G is required to…

Astrophysics · Physics 2008-11-26 K. C. Chan , M. -C. Chu

Using explicit perturbations of isotropic cosmological models which describe simple gravitational waves, an isotropic tensor having the algebraic symmetries of the Bel-Robinson tensor is derived as a model of cosmic background gravitational…

General Relativity and Quantum Cosmology · Physics 2011-05-09 P. A. Hogan , S. O'Farrell

Recent tentative findings of non-Gaussian structure in the COBE-DMR dataset have triggered renewed attention to candidate models from which such intrinsic signature could arise. In the framework of slow roll inflation with built-in non…

Astrophysics · Physics 2009-10-31 Alejandro Gangui , Jerome Martin

In a modified gravity theory, the propagation equation of gravitational waves will be presented in a non-standard way. Therefore this tenor mode perturbation of time-space, as a complement to the scalar mode perturbation, provides a unique…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Lixin Xu

In this paper, we introduce a new approach to a treatment of the gravitational effects (redshift, time delay and lensing) on the observed cosmic microwave background (CMB) anisotropies based on the Boltzmann equation. From the Liouville's…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-23 Ryo Saito , Atsushi Naruko , Takashi Hiramatsu , Misao Sasaki

We study scale dependence of the cosmic microwave background (CMB) power spectrum in a class of small, single-field models of inflation which lead to a high value of the tensor to scalar ratio. The inflaton potentials that we consider are…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-28 Ira Wolfson , Ram Brustein

Parameter estimation on gravitational wave signals from compact binary coalescence (CBC) requires the evaluation of computationally intensive waveform models, typically the bottleneck in the analysis. This cost will increase further as low…

General Relativity and Quantum Cosmology · Physics 2017-05-22 Serena Vinciguerra , John Veitch , Ilya Mandel

In light of the recent Planck 2015 results for the measurement of the CMB anisotropy, we study simple inflationary models in the context of the Gauss-Bonnet brane-world cosmology. The brane-world cosmological effect modifies the power…

High Energy Physics - Phenomenology · Physics 2017-03-15 Nobuchika Okada , Satomi Okada

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 present a complete set of formulae for calculating the bispectra of CMB temperature and polarization anisotropies generated from non-Gaussianity in the vector and tensor mode perturbations. In the all-sky analysis it is found that the…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-11 Maresuke Shiraishi , Shuichiro Yokoyama , Daisuke Nitta , Kiyotomo Ichiki , Keitaro Takahashi

In this paper we investigate gravitational waves production during the Big Bounce phase inspired by the Loop Quantum Cosmology. We consider the influence of the holonomy corrections to the equation for tensor modes. We show that they act…

General Relativity and Quantum Cosmology · Physics 2014-11-18 Jakub Mielczarek

In addition to density perturbations, inflationary models of the early universe generally predict a stochastic background of gravitational waves or tensor fluctuations. By making use of the inflationary flow approach for single field models…

Astrophysics · Physics 2008-11-26 Brett C. Friedman , Asantha Cooray , Alessandro Melchiorri

We develop a numerical scheme to make a high-frequency skymap of gravitational-wave backgrounds (GWBs) observed via space-based interferometer. Based on the cross-correlation technique, the intensity distribution of anisotropic GWB can be…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Atsushi Taruya

Weak lensing distortion of the background cosmic microwave background (CMB) temperature and polarization patterns by the foreground density fluctuations is well studied in the literature. We discuss the gravitational lensing modification to…

Astrophysics · Physics 2009-11-11 Chao Li , Asantha Cooray

Cosmic microwave background (CMB) observations provide in principle a high-precision test of models which are motivated by M theory. We set out the framework of a program to compute the tensor anisotropies in the CMB that are generated in…

Astrophysics · Physics 2009-11-07 Bernard Leong , Anthony Challinor , Roy Maartens , Anthony Lasenby