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Extracting information from cosmic surveys is often done in a two-step process, construction of maps and then summary statistics such as two-point functions. We use simulations to demonstrate the advantages of a general Bayesian framework…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-06 Alan Junzhe Zhou , Scott Dodelson

Analysis of cosmic shear is an integral part of understanding structure growth across cosmic time, which in-turn provides us with information about the nature of dark energy. Conventional methods generate \emph{shear maps} from which we can…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-02 Gregory Sallaberry , Benjamin W. Priest , Robert Armstrong , Michael D. Schneider , Amanda Muyskens , Trevor Steil , Keita Iwabuchi

The non-polarized points (NPP) of the $Q$ and $U$ Stokes parameters of the CMB can be classified according to the geometry of the polarization field. We describe a procedure to identify these points in the pixelized sky and present the…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-07 Jaan Kasak , James Creswell , Hao Liu , Pavel Naselsky

Hyper-spectral satellite imagery is now widely being used for accurate disaster prediction and terrain feature classification. However, in such classification tasks, most of the present approaches use only the spectral information contained…

Computer Vision and Pattern Recognition · Computer Science 2020-08-07 Shriya TP Gupta , Sanjay K Sahay

We present a novel Simultaneous Localization and Mapping (SLAM) method that employs Gaussian Process (GP) based landmark (object) representations. Instead of conventional grid maps or point cloud registration, we model the environment on a…

Robotics · Computer Science 2025-08-25 Ali Emre Balcı , Erhan Ege Keyvan , Emre Özkan

CMB polarization signal may be decomposed into gradient-like (E) and curl-like (B) mode. We have investigated E/B decomposition in pixel space. We find E/B mixing due to incomplete sky is localized in pixel-space, and negligible in the…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-22 Jaiseung Kim , Pavel Naselsky

We consider the reconstruction of the CMB lensing potential and its power spectrum of the full sphere in presence of sky-cuts due to point sources and Galactic contaminations. Those two effects are treated separately. Small regions…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-30 Aurélien Benoit-Lévy , Typhaine Déchelette , Karim Benabed , Jean-François Cardoso , Duncan Hanson , Simon Prunet

We present a new pseudospectral code, bamps, for numerical relativity written with the evolution of collapsing gravitational waves in mind. We employ the first order generalized harmonic gauge formulation. The relevant theory is reviewed…

General Relativity and Quantum Cosmology · Physics 2016-03-23 David Hilditch , Andreas Weyhausen , Bernd Bruegmann

We describe a system that builds a high dynamic-range and wide-angle image of the night sky by combining a large set of input images. The method makes use of pixel-rank information in the individual input images to improve a "consensus"…

Computer Vision and Pattern Recognition · Computer Science 2014-06-09 Dustin Lang , David W. Hogg , Bernhard Scholkopf

Weak gravitational lensing is one of the key probes of cosmology. Cosmic shear surveys aimed at measuring the distribution of matter in the universe are currently being carried out (Pan-STARRS) or planned for the coming decade (DES, LSST,…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-22 Alberto Vallinotto

Detailed measurements of the CMB lensing signal are an important scientific goal of ongoing ground-based CMB polarization experiments, which are mapping the CMB at high resolution over small patches of the sky. In this work we simulate CMB…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-30 Ruth Pearson , Blake Sherwin , Antony Lewis

Large scale structure deflects cosmic microwave background (CMB) photons. Since large angular scales in the large scale structure contribute significantly to the gravitational lensing effect, a realistic simulation of CMB lensing requires a…

Astrophysics · Physics 2009-11-13 Sudeep Das , Paul Bode

Skew-spectra allow us to extract non-Gaussian information by taking the square of a map and finding the power spectrum of this new map with the original map. This allows us to use much of the infrastructure of power spectra and avoid the…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-26 Alexander Roskill , Sara Maleubre , David Alonso , Pedro G. Ferreira

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

This work describes Cosmic Microwave Background (CMB) data analysis algorithms and their implementations, developed to produce a pixelized map of the sky and a corresponding pixel-pixel noise correlation matrix from time ordered data for a…

We present a CMB large-scale polarization dataset obtained by combining WMAP Ka, Q and V with Planck 70 GHz maps. We employ the legacy frequency maps released by the WMAP and Planck collaborations and perform our own Galactic foreground…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-04 U. Natale , L. Pagano , M. Lattanzi , M. Migliaccio , L. P. Colombo , A. Gruppuso , P. Natoli , G. Polenta

We present a new approach to component separation in multifrequency CMB experiments by formulating the problem as that of partitioning the sky into pixel clusters such that within each pixel cluster the foregrounds have similar spectrum,…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-18 Rishi Khatri

We introduce a novel meshless method called the Constrained Least-Squares Ghost Sample Points (CLS-GSP) method for solving partial differential equations on irregular domains or manifolds represented by randomly generated sample points. Our…

Numerical Analysis · Mathematics 2024-07-10 Ningchen Ying , Kwunlun Chu , Shingyu Leung

We present a multi-level solver for drawing constrained Gaussian realizations or finding the maximum likelihood estimate of the CMB sky, given noisy sky maps with partial sky coverage. The method converges substantially faster than existing…

Instrumentation and Methods for Astrophysics · Physics 2014-02-26 D. S. Seljebotn , K. -A. Mardal , J. B. Jewell , H. K. Eriksen , P. Bull

By actively distorting the Cosmic Microwave Background (CMB) over our past light cone, cosmic strings are unavoidable sources of non-Gaussianity. Developing optimal estimators able to disambiguate a string signal from the primordial type of…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-22 Christophe Ringeval , Francois R. Bouchet