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相关论文: A Statistic for the Detection of Long Strings in M…

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Using analytical methods and Monte Carlo simulations, we analyze new statistics designed to detect isolated step-like discontinuities which are coherent over large areas of Cosmic Microwave Background (CMB) pixel maps. Such coherent…

天体物理学 · 物理学 2011-05-10 L. Perivolaropoulos

A new statistic is briefly reviewed, designed to detect isolated coherent step-like discontinuities produced by cosmic strings present at late times. As a background I superpose a scale invariant Gaussian random field which could have been…

天体物理学 · 物理学 2007-05-23 Leandros Perivolaropoulos

ABSRACT: We review recent progress on testing the hypothesis of the existence of cosmic string perturbations in microwave background maps. Using an analytical model for the string network we show that the predicted amplitude and spectrum of…

天体物理学 · 物理学 2009-09-25 Leandros Perivolaropoulos , Richhild Moessner , Robert Brandenberger

We study the problem of searching for cosmic string signal patterns in the present high resolution and high sensitivity observations of the Cosmic Microwave Background (CMB). This article discusses a technique capable of recognizing…

宇宙学与河外天体物理 · 物理学 2014-11-20 E. Jeong , Carlo Baccigalupi , G. F. Smoot

An unexpected distribution of temperatures in the CMB could be a sign of new physics. In particular, the existence of cosmic defects could be indicated by temperature discontinuities via the Kaiser-Stebbins effect. In this paper, we show…

宇宙学与河外天体物理 · 物理学 2015-03-17 Jude Bowyer , Andrew H. Jaffe

We apply new statistical tests on the four year 53 GHz DMR data and show that there is significant probability for the existence of coherent temperature discontinuities hidden in the CMB maps around the Galactic Poles. Comparing Monte Carlo…

天体物理学 · 物理学 2007-05-23 L. Perivolaropoulos , N. Simatos

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

We propose a multi-scale edge-detection algorithm to search for the Gott-Kaiser-Stebbins imprints of a cosmic string (CS) network on the Cosmic Microwave Background (CMB) anisotropies. Curvelet decomposition and extended Canny algorithm are…

宇宙学与河外天体物理 · 物理学 2018-10-12 A. Vafaei Sadr , S. M. S. Movahed , M. Farhang , C. Ringeval , F. R. Bouchet

We introduce a new technique to detect the discrete temperature steps that cosmic strings might have left in the cosmic microwave background (CMB) anisotropy map. The technique provides a validity test on the pattern search of cosmic…

天体物理学 · 物理学 2009-11-11 E. Jeong , G. F. Smoot

In this paper we study the footprint of cosmic string as the topological defects in the very early universe on the cosmic microwave background radiation. We develop the method of level crossing analysis in the context of the well-known…

宇宙学与河外天体物理 · 物理学 2011-04-21 M. Sadegh Movahed , Shahram Khosravi

We use the publicly available code CMBFAST as modified by L. Pogosian and T. Vachaspati to simulate the effects of wiggly cosmic strings on the Cosmic Microwave Background (CMB). Using the modified CMBFAST code which takes into account…

天体物理学 · 物理学 2011-05-10 N. Simatos , L. Perivolaropoulos

We use the analytical model recently introduced in Ref. \cite{lp92}, to investigate the statistics of temperature fluctuations on the cosmic microwave background (CMB), induced by topological defects. The cases of cosmic strings and…

高能物理 - 唯象学 · 物理学 2010-11-01 Leandros Perivolaropoulos

We examine the two-point correlation function of local maxima in temperature fluctuations at the last scattering surface when this stochastic field is modified by the additional fluctuations produced by straight cosmic strings via the…

宇宙学与河外天体物理 · 物理学 2013-08-15 M. Sadegh Movahed , B. Javanmardi , Ravi K. Sheth

We present in detail the convolutional neural network used in our previous work to detect cosmic strings in cosmic microwave background (CMB) temperature anisotropy maps. By training this neural network on numerically generated CMB…

宇宙学与河外天体物理 · 物理学 2019-03-15 Razvan Ciuca , Oscar F. Hernández , Michael Wolman

Upcoming cosmic microwave background (CMB) experiments are expected to detect new signals probing interaction of CMB photons with intervening large-scale structure. Among these the moving-lens effect, the CMB temperature anisotropy induced…

宇宙学与河外天体物理 · 物理学 2024-01-24 Selim C. Hotinli , Elena Pierpaoli

Using a simple analytic model based on seed superposition we obtain the spectrum of microwave background perturbations induced by cosmic strings on all angular scales larger than about 2 armin. We assume standard recombination in an…

天体物理学 · 物理学 2011-05-10 Leandros Perivolaropoulos

We study the statistical properties of spherical harmonic modes of temperature maps of the cosmic microwave background. Unlike other studies, which focus mainly on properties of the amplitudes of these modes, we look instead at their…

天体物理学 · 物理学 2009-11-10 Peter Coles , Patrick Dineen , John Earl , Dean Wright

We present a new, semi-analytic framework for estimating the level of residuals present in CMB maps derived from multi-frequency Cosmic Microwave Background (CMB) data and forecasting their impact on cosmological parameters. The data are…

宇宙学与河外天体物理 · 物理学 2016-11-02 Radek Stompor , Josquin Errard , Davide Poletti

The detection of point-sources in microwave maps is a critical step in the analysis of the Cosmic Microwave Background (CMB) data. If not properly removed, these sources have adverse effects on the estimation of the power-spectrum and/or…

天体物理学 · 物理学 2009-07-14 R. Vio , P. Andreani

We construct a simple analytical model to study the effects of cosmic strings on the microwave background radiation. Our model is based on counting random multiple impulses inflicted on photon trajectories by the string network between the…

高能物理 - 唯象学 · 物理学 2009-10-22 Leandros Perivolaropoulos
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