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Cosmic strings, topological defects predicted by high-energy theories, may contribute to the late-time expansion of the Universe, effectively mimicking dynamical dark energy. We investigate four phenomenological extensions of the…

宇宙学与河外天体物理 · 物理学 2026-04-06 Hanyu Cheng , Eleonora Di Valentino , Luca Visinelli

Cosmological Birefringence (CB) is a phenomenon, caused by parity violating modifications to electrodynamics, whereby the linear polarisation angle of light changes as photons traverse a vacuum. It is possible to use a number of different…

宇宙学与河外天体物理 · 物理学 2020-09-04 Joel Williams , Aditya Rotti , Richard Battye

We continue our studies of the evolution and cosmological consequences of current-carrying cosmic string networks, described by a charge-velocity-dependent one scale (CVOS) model. We present a detailed calculation of the effects of these…

宇宙学与河外天体物理 · 物理学 2024-07-23 I. Yu. Rybak , C. J. A. P. Martins , Patrick Peter , E. P. S. Shellard

We propose a new method for a numerical computation of the angular bispectrum of the CMB anisotropies arising from active models such as cosmic topological defects, using a modified Boltzmann code based on CMBFAST. The method does not use…

天体物理学 · 物理学 2009-11-06 Alejandro Gangui , Levon Pogosian , Serge Winitzki

We report a search for signatures of cosmic strings in the the Cosmic Microwave Background data from the Wilkinson Microwave Anisotropy Probe. We used a digital filter designed to search for individual cosmic strings and found no evidence…

天体物理学 · 物理学 2007-05-23 Amy S. Lo , Edward L. Wright

We briefly review certain aspects of cosmic microwave background anisotropies as generated in passive and active models of structure formation. We then focus on cosmic strings based models and discuss their status in the light of current…

天体物理学 · 物理学 2009-11-07 Alejandro Gangui , Levon Pogosian , Serge Winitzki

The cosmic microwave background (CMB) is affected by the total radiation density around the time of decoupling. At that epoch, neutrinos comprised a significant fraction of the radiative energy, but there could also be a contribution from…

宇宙学与河外天体物理 · 物理学 2013-05-30 Irene Sendra , Tristan L. Smith

One of the most powerful cosmological datasets when it comes to constraining neutrino masses is represented by galaxy power spectrum measurements, $P_{gg}(k)$. The constraining power of $P_{gg}(k)$ is however severely limited by…

宇宙学与河外天体物理 · 物理学 2019-03-18 Elena Giusarma , Sunny Vagnozzi , Shirley Ho , Simone Ferraro , Katherine Freese , Rocky Kamen-Rubio , Kam-Biu Luk

We investigate the effect of wiggly cosmic strings on the cosmic microwave background radiation anisotropy and matter power spectrum by modifying the string network model used by Albrecht et al.. We employ the wiggly equation of state for…

天体物理学 · 物理学 2016-08-25 Levon Pogosian , Tanmay Vachaspati

Primordial statistical anisotropy is a key indicator to investigate early Universe models and has been probed by the cosmic microwave background (CMB) anisotropies. In this paper, we examine tensor-mode CMB fluctuations generated from…

宇宙学与河外天体物理 · 物理学 2014-07-29 Maresuke Shiraishi , David F. Mota , Angelo Ricciardone , Frederico Arroja

Ever since the Planck satellite measured the the cosmic microwave background (CMB) down to arcminute angular scales, the mismatch between the CMB-inferred value of the Hubble constant and the value inferred from the distance ladder (i.e.,…

宇宙学与河外天体物理 · 物理学 2025-05-01 Tristan L. Smith , Nils Schöneberg

The latest Planck results show a power deficit in the temperature anisotropies near $\ell \approx 20$ in the cosmic microwave background (CMB). This observation can hardly be explained within the standard inflationary…

宇宙学与河外天体物理 · 物理学 2016-01-05 Yi-Fu Cai , Elisa G. M. Ferreira , Bin Hu , Jerome Quintin

We showed that the part of strings could be detected by optical method is only 20% from the total available amount of such objects, therefore the gravitational lensing method has to be "completed" by CMB one. We found the general structure…

天体物理学 · 物理学 2009-11-13 O. S. Sazhina , M. V. Sazhin , V. N. Sementsov , M. Capaccioli , G. Longo , G. Riccio , G. D'Angelo

We perform a Fisher matrix calculation of the predicted uncertainties on estimates of the cosmic string tension Gmu from upcoming observational data (namely, cosmic microwave background power spectra from the Planck satellite and an…

宇宙学与河外天体物理 · 物理学 2011-08-22 Simon Foreman , Adam Moss , Douglas Scott

We perform a multiparameter likelihood analysis to compare measurements of the cosmic microwave background (CMB) power spectra with predictions from models involving cosmic strings. Adding strings to the standard case of a primordial…

天体物理学 · 物理学 2008-11-26 Neil Bevis , Mark Hindmarsh , Martin Kunz , Jon Urrestilla

We devise a measure n(r) to quantify a robust feature in the coherent cosmic perturbations, namely the narrowness of the first peak in the power spectrum of the Cosmic Microwave Background (CMB) anisotropy. A maximum-likelihood analysis…

天体物理学 · 物理学 2007-05-23 Jiun-Huei Proty Wu

We study the observational signature of vector metric perturbations through the effect of weak gravitational lensing. In the presence of vector perturbations, the non-vanishing signals for B-mode cosmic shear and curl-mode deflection angle,…

宇宙学与河外天体物理 · 物理学 2015-06-05 Daisuke Yamauchi , Toshiya Namikawa , Atsushi Taruya

Cosmic Microwave Background (CMB) anisotropy encodes a lot of information about our Universe. In this paper we take the ground-based CMB observations (GCMB), including the South Pole Telescope (SPT), SPTpol and the Atacama Cosmology…

宇宙学与河外天体物理 · 物理学 2020-07-01 Ke Wang , Qing-Guo Huang

We compare the anisotropies in the cosmic microwave background radiation measured by the COBE experiment to the predictions of cosmic strings. We use an analytic model for the $\Delta T/T$ power spectrum that is based on our previous…

高能物理 - 唯象学 · 物理学 2009-10-22 David P. Bennett , Albert Stebbins , Francois R. Bouchet

In this paper, we explore the power of the cosmic microwave background (CMB) polarization (E-mode) data to corroborate four potential anomalies in CMB temperature data: the lack of large angular-scale correlations, the alignment of the…