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This paper generalises the hybrid power spectrum estimator developed in Efstathiou (2004a) to the estimation of polarization power spectra of the cosmic microwave background radiation. The hybrid power spectrum estimator is unbiased and we…

Astrophysics · Physics 2009-11-11 G. Efstathiou

Constructing a fast and efficient estimator for the B-mode power spectrum of cosmic microwave background (CMB) is of critical importance for CMB science. For a general CMB survey, the Quadratic Maximum Likelihood (QML) estimator for CMB…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-17 Jiming Chen , Shamik Ghosh , Hao Liu , Larissa Santos , Wenjuan Fang , Siyu Li , Yang Liu , Hong Li , Jiaxin Wang , Le Zhang , Bin Hu , Wen Zhao

One of the fundamental problems in extracting the cosmic microwave background signal (CMB) from millimeter/submillimeter observations is the pollution by emission from the Milky Way: synchrotron, free-free, and thermal dust emission. To…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 H. U. Nørgaard - Nielsen

We investigate the impact of beam chromaticity, i.e., the frequency dependence of the beam window function, on cosmological and astrophysical parameter constraints from CMB power spectrum observations. We show that for future…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-18 S. Giardiello , A. J. Duivenvoorden , E. Calabrese , G. Galloni , M. Hasselfield , J. C. Hill , A. La Posta , T. Louis , M. Madhavacheril , L. Pagano

We derive a general ansatz for optimizing pseudo-C_l estimators used to measure CMB anisotropy power spectra, and apply it to the recently-proposed pure pseudo-C_l formalism, to obtain an estimator which achieves near-optimal B-mode power…

Astrophysics · Physics 2008-11-26 Kendrick M. Smith , Matias Zaldarriaga

The extraction of foreground and CMB maps from multi-frequency observations relies mostly on the different frequency behavior of the different components. Existing Bayesian methods additionally make use of a Gaussian prior for the CMB whose…

Instrumentation and Methods for Astrophysics · Physics 2014-07-04 Niels Oppermann , Torsten A. Enßlin

Accurate uncertainty quantification is crucial for the safe deployment of machine learning models, and prior research has demonstrated improvements in the calibration of modern language models (LMs). We study in-context learning (ICL), a…

Computation and Language · Computer Science 2024-03-29 Hanlin Zhang , Yi-Fan Zhang , Yaodong Yu , Dhruv Madeka , Dean Foster , Eric Xing , Himabindu Lakkaraju , Sham Kakade

In our previous study, we introduced a machine-learning technique, namely CMBFSCNN, for the removal of foreground contamination in cosmic microwave background (CMB) polarization data. This method was successfully employed on actual…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-19 Ye-Peng Yan , Si-Yu Li , Guo-Jian Wang , Zirui Zhang , Jun-Qing Xia

Extraction of the CMB (Cosmic Microwave Background) angular power spectrum is a challenging task for current and future CMB experiments due to the large data sets involved. Here we describe an implementation of MASTER (Monte carlo Apodised…

Astrophysics · Physics 2009-11-10 T. Poutanen , D. Maino , H. Kurki-Suonio , E. Keihanen , E. Hivon

In-context learning (ICL) has emerged as a powerful capability for large language models (LLMs) to adapt to downstream tasks by leveraging a few (demonstration) examples. Despite its effectiveness, the mechanism behind ICL remains…

Machine Learning · Computer Science 2025-06-03 Pengfei He , Yingqian Cui , Han Xu , Hui Liu , Makoto Yamada , Jiliang Tang , Yue Xing

The Cosmic Microwave Background (CMB) is a fundamental observational tool in modern cosmology. The linear polarization of the CMB provides a crucial observational tool for exploring new physics, including the inflationary paradigm and…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-12 Vyoma Muralidhara

The polarization of the Cosmic Microwave Background (CMB)is a powerful observational tool at hand for modern cosmology. It allows to break the degeneracy of fundamental cosmological parameters one cannot obtain using only anisotropy data…

Astrophysics · Physics 2009-11-07 M. V. Sazhin , G. Sironi , O. S. Khovanskaya

The lensing power spectrum from cosmic microwave background (CMB) temperature maps will be measured with unprecedented precision with upcoming experiments, including upgrades to ACT and SPT. Achieving significant improvements in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 A. van Engelen , S. Bhattacharya , N. Sehgal , G. P. Holder , O. Zahn , D. Nagai

A key goal of many Cosmic Microwave Background experiments is the detection of gravitational waves, through their B-mode polarization signal at large scales. To extract such a signal requires modelling contamination from the Galaxy. Using…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Charmaine Armitage-Caplan , Joanna Dunkley , Hans Kristian Eriksen , Clive Dickinson

Cross-correlating the lensing signals of galaxies and comic microwave background (CMB) fluctuations is expected to provide valuable cosmological information. In particular it may help tighten constraints on parameters describing the…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-14 Philipp M. Merkel , Bjoern Malte Schaefer

Cosmic microwave background radiation (CMB) observations are unavoidably contaminated by emission from various extra-galactic foregrounds, which must be removed to obtain reliable measurements of the cosmological signal. In this paper, we…

We present a new method based on phase analysis for the Galaxy and foreground component separation from the cosmic microwave background (CMB) signal. This method is based on a prevailing assumption that the phases of the underlying CMB…

Astrophysics · Physics 2007-05-23 Pavel D. Naselsky , Oleg V. Verkhodanov , Lung-Yih Chiang , Igor D. Novikov

We estimate Cosmic Microwave Background (CMB) polarisation power spectra, and temperature-polarisation cross-spectra, from the 9-year data of the Wilkinson Microwave Anisotropy Probe (WMAP). Foreground cleaning is implemented using minimum…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-02 Soumen Basak , Jacques Delabrouille

Upcoming surveys will measure the cosmic microwave background (CMB) weak lensing power spectrum in exquisite detail, allowing for strong constraints on the sum of neutrino masses among other cosmological parameters. Standard CMB lensing…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-23 Delon Shen , Emmanuel Schaan , Simone Ferraro

Prompting and in-context learning (ICL) have become efficient learning paradigms for large language models (LLMs). However, LLMs suffer from prompt brittleness and various bias factors in the prompt, including but not limited to the…

Computation and Language · Computer Science 2024-12-03 Han Zhou , Xingchen Wan , Lev Proleev , Diana Mincu , Jilin Chen , Katherine Heller , Subhrajit Roy
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