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Estimating the cosmological microwave background is of utmost importance for cosmology. However, its estimation from full-sky surveys such as WMAP or more recently Planck is challenging: CMB maps are generally estimated via the application…

宇宙学与河外天体物理 · 物理学 2015-06-03 J. Bobin , J. -L. Starck , F. Sureau , J. Fadili

We propose a Bayesian approach to joint source separation and restoration for astrophysical diffuse sources. We constitute a prior statistical model for the source images by using their gradient maps. We assume a t-distribution for the…

天体物理仪器与方法 · 物理学 2015-05-20 K. Kayabol , J. L. Sanz , D. Herranz , E. E. Kuruoglu , E. Salerno

We review the well-known matched filter method for the detection of point sources in astronomical images. This is shown to be optimal (that is, to saturate the Cramer--Rao bound) under stated conditions that are very strong: an isolated…

天体物理仪器与方法 · 物理学 2021-01-01 Dustin Lang , David W. Hogg

Recently, the maximum a posteriori (MAP) probability rule has been proposed as an objective and quantitative method to detect atom columns and even single atoms from high-resolution high-angle annular dark-field (HAADF) scanning…

数据分析、统计与概率 · 物理学 2019-02-18 J. Fatermans , S. Van Aert , A. J. den Dekker

We describe an efficient and exact method that enables global Bayesian analysis of cosmic microwave background (CMB) data. The method reveals the joint posterior density (or likelihood for flat priors) of the power spectrum $C_\ell$ and the…

天体物理学 · 物理学 2009-11-10 Benjamin D. Wandelt , David L. Larson , Arun Lakshminarayanan

We present an algorithm capable of detecting diffuse, dim sources of any size in an astronomical image. These sources often defeat traditional methods for source finding, which expand regions around points of high intensity. Extended…

天体物理仪器与方法 · 物理学 2016-01-05 T. Butler-Yeoman , M. Frean , C. P. Hollitt , D. W. Hogg , M. Johnston-Hollitt

We extend the internal template foreground removal method by accounting for spatially varying spectral parameters such as the spectral indices of synchrotron and dust emission and the dust temperature. As the previous algorithm had to…

宇宙学与河外天体物理 · 物理学 2019-02-04 Kiyotomo Ichiki , Hiroaki Kanai , Nobuhiko Katayama , Eiichiro Komatsu

We develop a new Bayesian method for estimating white noise levels in CMB sky maps, and apply this algorithm to the 5-year WMAP data. We assume that the amplitude of the noise RMS is scaled by a constant value, alpha, relative to a…

宇宙学与河外天体物理 · 物理学 2009-08-24 N. E. Groeneboom , H. K. Eriksen , K. Gorski , G. Huey , J. Jewell , B. Wandelt

Cosmic microwave background (CMB) temperature anisotropies follow a Gaussian statistical distribution in the standard inflationary model, but there are non-Gaussian contributions due to astrophysical foregrounds. The detection of the…

天体物理学 · 物理学 2009-11-11 F. Argueso , J. L. Sanz , R. B. Barreiro , D. Herranz , J. Gonzalez-Nuevo

A number of well-motivated extensions of the LCDM concordance cosmological model postulate the existence of a population of sources embedded in the cosmic microwave background (CMB). One such example is the signature of cosmic bubble…

宇宙学与河外天体物理 · 物理学 2012-05-29 J. D. McEwen , S. M. Feeney , M. C. Johnson , H. V. Peiris

A Bayesian approach is presented for detecting and characterising the signal from discrete objects embedded in a diffuse background. The approach centres around the evaluation of the posterior distribution for the parameters of the discrete…

天体物理学 · 物理学 2009-11-07 M. P. Hobson , C. McLachlan

In order to extract cosmological information from observations of the millimeter and submillimeter sky, foreground components must first be removed to produce an estimate of the cosmic microwave background (CMB). We developed a…

宇宙学与河外天体物理 · 物理学 2020-11-10 Matthew A. Petroff , Graeme E. Addison , Charles L. Bennett , Janet L. Weiland

We describe a method for deriving the position and flux of point and compact sources observed by a scanning survey mission. Results from data simulated to test our method are presented, which demonstrate that at least a 10-fold improvement…

天体物理仪器与方法 · 物理学 2015-05-13 F. van Leeuwen , A. N. Morgan , D. L. Harrison

Estimation of the angular power spectrum of the Cosmic Microwave Background (CMB) on a small patch of sky is usually plagued by serious spectral leakage, specially when the map has a hard edge. Even on a full sky map, point source masks can…

天体物理学 · 物理学 2009-11-06 Sudeep Das , Amir Hajian , David N. Spergel

We characterize the Cosmic Infrared Background (CIB)-lensing bispectrum which is one of the contributions to the three-point functions of Cosmic Microwave Background (CMB) maps in harmonic space. We show that the CIB-lensing bispectrum has…

宇宙学与河外天体物理 · 物理学 2015-05-27 A. Curto , M. Tucci , M. Kunz , E. Martinez-Gonzalez

In this paper, we aim to design robust estimation techniques based on the compound-Gaussian (CG) process and adapted for calibration of radio interferometers. The motivation beyond this is due to the presence of outliers leading to an…

We use an iterative generalized least squares map-making algorithm, in conjunction with Monte Carlo techniques, to obtain estimates of the angular power spectrum from cosmic microwave background (CMB) maps. This is achieved by…

天体物理学 · 物理学 2009-11-07 A. Balbi , G. de Gasperis , P. Natoli , N. Vittorio

We present a statistical method based on a maximum likelihood approach to constrain the number counts of extragalactic sources below the nominal flux-density limit of continuum imaging surveys. We extract flux densities from a radio map…

天体物理仪器与方法 · 物理学 2015-06-16 Ketron Mitchell-Wynne , Mario G. Santos , Jose Afonso , Matt J. Jarvis

We present a parallel implementation of a map-making algorithm for CMB anisotropy experiments which is both fast and efficient. We show for the first time a Maximum Likelihood, minimum variance map obtained by processing the entire data…

天体物理学 · 物理学 2014-10-13 P. Natoli , G. de Gasperis , C. Gheller , N. Vittorio

It has been pointed out that the spurious Cosmic Microwave Background (CMB) B-mode polarization signals caused by the absorption of the CMB monopole component due to the Galactic interstellar matter, called the CMB shadow, degrade the…

宇宙学与河外天体物理 · 物理学 2023-06-05 Tamaki Murokoshi , Yuji Chinone , Masashi Nashimoto , Kiyotomo Ichiki , Makoto Hattori