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Efficient computation of the angular bispectrum is an essential part of modelling large-scale structure observations, but it still remains an extremely challenging task. In this work, we compute the tree-level, unequal-time angular…

宇宙学与河外天体物理 · 物理学 2026-05-29 Zucheng Gao , Zvonimir Vlah , Anthony Challinor

A full-sky template map of the Galactic free-free foreground emission component is increasingly important for high sensitivity CMB experiments. We use the recently published \ha data of both the northern and southern skies as the basis for…

天体物理学 · 物理学 2009-11-07 C. Dickinson , R. D. Davies , R. J. Davis

We present a general method for accelerating by more than an order of magnitude the convolution of pixelated function on the sphere with a radially-symmetric kernel. Our method splits the kernel into a compact real-space, and a compact…

天体物理仪器与方法 · 物理学 2012-11-16 P. M. Sutter , Benjamin D. Wandelt , Franz Elsner

Detection of magnetic-type ($B$-type) polarization in the Cosmic Microwave Background (CMB) radiation plays a crucial role in probing the relic gravitational wave (RGW) background. In this paper, we propose a new method to deconstruct a…

宇宙学与河外天体物理 · 物理学 2015-03-17 Wen Zhao , Deepak Baskaran

The standard model of cosmology predicts a statistically isotropic (SI) CMB sky. However, the SI violation signals are always present in an observed sky-map. Different cosmological artifacts, measurement effects and unavoidable effects…

宇宙学与河外天体物理 · 物理学 2019-09-25 Santanu Das

We propose and implement a fast, universally applicable method for extracting the angular power spectrum C_l from CMB temperature maps by first estimating the correlation function \xi(\theta). Our procedure recovers the C_l's using N^2 (but…

天体物理学 · 物理学 2007-05-23 Istvan Szapudi , Simon Prunet , Dmitry Pogosyan , Alexander S. Szalay , J. Richard Bond

Gravitational lensing of the CMB is a valuable cosmological signal that correlates to tracers of large-scale structure and acts as a important source of confusion for primordial $B$-mode polarization. State-of-the-art lensing reconstruction…

宇宙学与河外天体物理 · 物理学 2019-02-05 Julien Carron , Antony Lewis

The measurements of CMB anisotropy have opened up a window for probing the global topology of the universe on length scales comparable to and beyond the Hubble radius. We have developed a new method for calculating the CMB anisotropy in…

天体物理学 · 物理学 2007-05-23 Tarun Souradeep , Dmitry Pogosyan , J. Richard Bond

We present a novel method to significantly speed up cosmological parameter sampling. The method relies on constructing an interpolation of the CMB-log-likelihood based on sparse grids, which is used as a shortcut for the…

宇宙学与河外天体物理 · 物理学 2015-05-18 Mona Frommert , Dirk Pflueger , Thomas Riller , Martin Reinecke , Hans-Joachim Bungartz , Torsten Ensslin

Hyperspectral imaging has become a significant source of valuable data for astronomers over the past decades. Current instrumental and observing time constraints allow direct acquisition of multispectral images, with high spatial but low…

计算机视觉与模式识别 · 计算机科学 2019-12-30 Claire Guilloteau , Thomas Oberlin , Olivier Berné , Nicolas Dobigeon

The Universe is not perfectly homogeneous, the large scale structure forms overdense regions and voids. In this paper, we consider the possibility that we occupy a special position in our Universe, close to the center of a local underdense…

宇宙学与河外天体物理 · 物理学 2019-12-13 Viraj Nistane , Giulia Cusin , Martin Kunz

A novel application of machine-learning (ML) based image processing algorithms is proposed to analyze an all-sky map (ASM) obtained using the Fermi Gamma-ray Space Telescope. An attempt was made to simulate a one-year ASM from a…

高能天体物理现象 · 物理学 2021-06-02 Shogo Sato , Jun Kataoka , Soichiro Ito , Jun'ichi Kotoku , Masato Taki , Asuka Oyama , Takaya Toyoda , Yuki Nakamura , Marino Yamamoto

We develop a method of reconstructing the lensing field from lensed CMB temperature and polarization maps in real space as an alternative to the harmonic space estimators currently in use by extending an existing real space lensing…

宇宙学与河外天体物理 · 物理学 2018-02-07 Heather Prince , Kavilan Moodley , Jethro Ridl , Martin Bucher

A fast algorithm (linear in the degrees of freedom) for the solution of linear variable-coefficient rational-order fractional integral and differential equations is described. The approach is related to the ultraspherical method for…

数值分析 · 数学 2017-12-04 Nicholas Hale , Sheehan Olver

We propose a machine learning approach to the blind detection of extragalactic point sources on maps of the temperature anisotropies of the cosmic microwave background. Using realistic simulations of the microwave sky as seen by Planck, we…

宇宙学与河外天体物理 · 物理学 2023-03-01 P. Diego-Palazuelos , R. B. Barreiro , P. Vielva , D. Balbás , M. López-Caniego , D. Herranz , B. Casaponsa

We describe an algorithm for the extraction of the angular power spectrum of an intensity field, such as the cosmic microwave background (CMB), from interferometer data. This new method, based on the gridding of interferometer visibilities…

We introduce a new mathematical tool (a direction-dependent probe) to analyse the randomness of purported isotropic Gaussian random fields on the sphere. We apply the probe to assess the full-sky cosmic microwave background (CMB)…

宇宙学与河外天体物理 · 物理学 2020-06-29 J. Hamann , Q. T. Le Gia , I. H. Sloan , Y. G. Wang , R. S. Womersley

We introduce a publicly available full-sky beam convolution code library intended to inform the design of future cosmic microwave background (CMB) instruments and help current experiments probe potential systematic effects. The code can be…

天体物理仪器与方法 · 物理学 2019-05-08 Adriaan J. Duivenvoorden , Jon E. Gudmundsson , Alexandra S. Rahlin

We develop a computationally efficient and robust algorithm for generating pseudo-random samples from a broad class of smooth probability distributions in one and two dimensions. The algorithm is based on inverse transform sampling with a…

数值分析 · 数学 2013-07-05 Sheehan Olver , Alex Townsend

CMB anisotropy experiments seeking to make maps with more pixels than the 6144 pixels used by the COBE DMR need to address the practical issues of the computer time and storage required to make maps. A simple, repetitive scan pattern…

天体物理学 · 物理学 2007-05-23 Edward L. Wright