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Internal Linear Combination (ILC) methods are some of the most widely used multi-frequency cleaning techniques employed in CMB data analysis. These methods reduce foregrounds by minimizing the total variance in the coadded map (subject to a…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-19 Y. Sultan Abylkairov , Omar Darwish , J. Colin Hill , Blake D. Sherwin

The `Internal Linear Combination' (ILC) component separation method has been extensively used on the data of the WMAP space mission, to extract a single component, the CMB, from the WMAP multifrequency data. We extend the ILC approach for…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Mathieu Remazeilles , Jacques Delabrouille , Jean-Francois Cardoso

A new method for estimating the angular power spectrum C_l from cosmic microwave background (CMB) maps is presented, which has the following desirable properties: (1) It is unbeatable in the sense that no other method can measure C_l with…

Astrophysics · Physics 2009-10-07 Max Tegmark

The method of weighted addition of multi-frequency maps, more commonly referred to as {\it Internal Linear Combination} (ILC), has been extensively employed in the measurement of cosmic microwave background (CMB) anisotropies and its…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-28 Aditya Rotti , Jens Chluba

In this article we present a formalism to incorporate the partial-sky maps to the Gibbs ILC algorithm to estimate the joint posterior density of the Cosmic Microwave Background (CMB) signal and the theoretical CMB angular power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-14 Vipin Sudevan , Ujjal Purkayastha , Rajib Saha

The Independent Component Analysis (ICA) algorithm is implemented as a neural network for separating signals of different origin in astrophysical sky maps. Due to its self-organizing capability, it works without prior assumptions on the…

We are presenting an Internal Linear Combination (ILC) CMB map, in which the foreground is reduced through harmonic variance minimization. We have derived our method by converting a general form of pixel-space approach into spherical…

Astrophysics · Physics 2009-09-29 Jaiseung Kim , Pavel Naselsky , Per Rex Christensen

All-sky maps of the thermal Sunyaev-Zel'dovich effect (SZ) tend to suffer from systematic features arising from the component separation techniques used to extract the signal. In this work, we investigate one of these methods known as…

Instrumentation and Methods for Astrophysics · Physics 2024-02-02 Cameron T. Pratt , Zhijie Qu , Joel N. Bregman , Christopher J. Miller

We have derived whole-sky CMB polarization maps from the WMAP 5 year polarization data, using the Harmonic Internal Linear Combination (HILC) method. Our HILC method incorporates spatial variability of linear weights in a natural way and…

Astrophysics · Physics 2009-04-06 Jaiseung Kim , Pavel Naselsky , Per Rex Christensen

I will briefly present my work on cosmological parameters estimation. Classical methods for parameters estimation involve the exploration of the parameter space on a precalculated grid of cosmological models. Here we try to estimate the…

Astrophysics · Physics 2007-05-23 Stephane Bargot

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

Analysis of microwave sky signals, such as the cosmic microwave background, often requires component separation with multi-frequency methods, where different signals are isolated by their frequency behaviors. Many so-called "blind" methods,…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-02 Fiona McCarthy , J. Colin Hill , William R. Coulton , David W. Hogg

We have developed a fast, accurate and generally applicable method for inferring the power spectrum and its uncertainties from maps of the cosmic microwave background (CMB) in the presence of inhomogeneous and correlated noise. For maps…

Astrophysics · Physics 2014-10-13 O. Doré , L. Knox , A. Peel

The detection of primordial polarization $B$ modes of the Cosmic Microwave Background (CMB) requires exquisite control of Galactic foreground contamination. The Needlet Internal Linear Combination (NILC) method has proven effective in…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-25 Alessandro Carones

We explore a novel analysis framework for parameter inference with large-scale CMB polarization data. Our method uses simulation-based inference combined with the needlet internal linear combination (NILC) algorithm and…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-19 Adriaan J. Duivenvoorden , Kristen Surrao , Adrian E. Bayer , Alexandre E. Adler , Nadia Dachlythra , Susanna Azzoni , J. Colin Hill

To create high-fidelity cosmic microwave background maps, current component separation methods rely on availability of information on different foreground components, usually through multi-band frequency coverage of the instrument. Internal…

Instrumentation and Methods for Astrophysics · Physics 2023-06-02 Guillermo F. Quispe Peña , Andrei V. Frolov

The aim of this work is to propose a joint exploitation of heterogeneous datasets from high-resolution/few-channel experiments and low-resolution/many-channel experiments by using a multiscale needlet Internal Linear Combination (ILC), in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Mathieu Remazeilles , Nabila Aghanim , Marian Douspis

Cosmic birefringence, arising from a potential parity-violating interaction between cosmic microwave background (CMB) photons and evolving pseudo-scalar fields such as axion-like particles, can rotate the CMB polarization plane and induce…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-27 Mathieu Remazeilles

Residual foreground contamination in thermal Sunyaev-Zeldovich (SZ) Compton-$y$ parameter maps ($y$-maps) arises mainly from Galactic emissions -- thermal dust and synchrotron radiation -- on large angular scales, and from cosmic infrared…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-19 Jyothis Chandran , Mathieu Remazeilles , R. B. Barreiro