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We explore the use of random forest and gradient boosting, two powerful tree-based machine learning algorithms, for the detection of cosmic strings in maps of the cosmic microwave background (CMB), through their unique Gott-Kaiser-Stebbins…

宇宙学与河外天体物理 · 物理学 2018-10-12 A. Vafaei Sadr , M. Farhang , S. M. S. Movahed , B. Bassett , M. Kunz

The current suite of results from Cosmic Microwave Background anisotropy experiments is fulfilling the promise of providing extraordinary levels of discrimination between cosmological models. We calculate a binned anisotropy power spectrum,…

天体物理学 · 物理学 2007-05-23 Elena Pierpaoli , Douglas Scott , Martin White

The low quadrupole of the cosmic microwave background (CMB), measured by COBE and confirmed by WMAP, has generated much discussion recently. We point out that the well-known correlation between temperature and polarization anisotropies of…

天体物理学 · 物理学 2009-06-15 Olivier Doré , Gilbert P. Holder , Abraham Loeb

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 study how the presence of world-sheet currents affects the evolution of cosmic string networks, and their impact on predictions for the cosmic microwave background (CMB) anisotropies generated by these networks. We provide a general…

宇宙学与河外天体物理 · 物理学 2020-10-21 I. Yu. Rybak , A. Avgoustidis , C. J. A. P. Martins

We investigate the power spectrum of the distortion of Cosmic Microwave Background (CMB) due to the decay of the primordial magnetic fields. It is known that there are two-types of the CMB distortions, so-called \mu- and y-types and we find…

宇宙学与河外天体物理 · 物理学 2014-03-12 Koichi Miyamoto , Toyokazu Sekiguchi , Hiroyuki Tashiro , Shuichiro Yokoyama

We analyse the large-scale coherence of the CMB anisotropy field with non-gaussian initial conditions usind 2-point function of the power fluctuations in the wavelet space. Employing the multivariate Edgeworth expansion (MEE) we constrain…

天体物理学 · 物理学 2009-10-30 Lucia Popa

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 present a significant update of the constraints on the Abelian Higgs cosmic string tension by cosmic microwave background (CMB) data, enabled both by the use of new high-resolution CMB data from suborbital experiments as well as the…

宇宙学与河外天体物理 · 物理学 2015-05-30 J. Urrestilla , N. Bevis , M. Hindmarsh , M. Kunz

We present a new analytical method to calculate the small angle CMB temperature angular power spectrum due to cosmic (super-)string segments. In particular, using our method, we clarify the dependence on the intercommuting probability $P$.…

宇宙学与河外天体物理 · 物理学 2014-11-21 Daisuke Yamauchi , Keitaro Takahashi , Yuuiti Sendouda , Chul-Moon Yoo , Misao Sasaki

The advent of high resolution cosmic microwave background (CMB) experiments now allows studies on the temperature fluctuations at scales corresponding to few arcminutes and below. Though the reported excess power at $\ell \sim 2000 - 6000$…

天体物理学 · 物理学 2009-11-07 Asantha Cooray , Alessandro Melchiorri

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

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…

天体物理学 · 物理学 2009-10-22 Naoshi Sugiyama

Line discontinuities in cosmic microwave background anisotropy maps are a distinctive prediction of models with cosmic strings. These signatures are visible in anisotropy maps with good angular resolution and should be identifiable using…

天体物理学 · 物理学 2009-06-23 Stephen Amsel , Joshua Berger , Robert H. Brandenberger

We explore the large angular scale temperature anisotropies in the cosmic microwave background (CMB) due to homogeneous local dust-filled voids in a flat Friedmann-Robertson-Walker universe with a cosmological constant. In comparison with…

天体物理学 · 物理学 2008-11-26 Kaiki Taro Inoue , Joseph Silk

Since the discovery of the Cosmic Microwave Background (CMB) in 1965, characterization of the CMB anisotropy angular power spectrum has become somewhat of a holy grail for experimental cosmology. Because CMB anisotropy measurements are…

天体物理学 · 物理学 2017-08-23 A. D. Miller

We investigate cosmological evolution and implications of cosmic strings with time-dependent tension. We derive basic equations of time development of the correlation length and the velocity of such strings, based on the one scale model.…

高能物理 - 唯象学 · 物理学 2008-11-26 Kazuhide Ichikawa , Tomo Takahashi , Masahide Yamaguchi

Using an analytic model we show that the predictions of the cosmic string model for the peculiar velocities and the microwave background (MBR) anisotropy depend on similar combinations of string evolution parameters. Normalizing from the…

高能物理 - 唯象学 · 物理学 2009-10-22 L. Perivolaropoulos , T. Vachaspati

The breakdown of statistical homogeneity and isotropy of cosmic perturbations is a generic feature of ultra large scale structure of the cosmos, in particular, of non trivial cosmic topology. The statistical isotropy (SI) of the Cosmic…

天体物理学 · 物理学 2008-11-26 Tarun Souradeep , Amir Hajian

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