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Compressed Sensing suggests that the required number of samples for reconstructing a signal can be greatly reduced if it is sparse in a known discrete basis, yet many real-world signals are sparse in a continuous dictionary. One example is…

Information Theory · Computer Science 2015-07-24 Yuanxin Li , Yuejie Chi

We consider the recovery of signals from their observations, which are samples of a transform of the signals rather than the signals themselves, by using machine learning (ML). We will develop a theoretical framework to characterize the…

Machine Learning · Computer Science 2019-10-08 Hong Jiang , Jong-Hoon Ahn , Xiaoyang Wang

We present a global measurement of the integrated Sachs-Wolfe (ISW) effect obtained by cross-correlating all relevant large scale galaxy data sets with the cosmic microwave background radiation map provided by the Wilkinson Microwave…

We investigate the possibility to detect the integrated Sachs-Wolfe (ISW) effect by cross-correlating 21-cm surveys at high redshifts with galaxies, in a way similar to the usual CMB-galaxy cross-correlation. The high-redshift 21-cm signal…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-20 Alvise Raccanelli , Ely Kovetz , Liang Dai , Marc Kamionkowski

We study the behavior of light rays in perturbed Robertson-Walker cosmologies, calculating the redshift between an observer and the surface of last scattering to second order in the metric perturbation. At first order we recover the classic…

Astrophysics · Physics 2008-11-26 Ted Pyne , Sean M. Carroll

Filtering is a widely used methodology for the incorporation of observed data into time-evolving systems. It provides an online approach to state estimation inverse problems when data is acquired sequentially. The Kalman filter plays a…

Probability · Mathematics 2015-05-27 Wonjung Lee , Damon McDougall , Andrew Stuart

We describe techniques for comparing spectra extracted from cosmological simulations and observational data, using the same methodology to link Lyman-alpha properties derived from the simulations with properties derived from observational…

Astrophysics · Physics 2009-11-07 C. E. Petry , C. D. Impey , N. Katz , D. H. Weinberg , L. E. Hernquist

We consider the problem of recovering linear image of unknown signal belonging to a given convex compact signal set from noisy observation of another linear image of the signal. We develop a simple generic efficiently computable nonlinear…

Statistics Theory · Mathematics 2019-04-12 Anatoli Juditsky , Arkadi Nemirovski

We describe a new technique for removing troublesome interference from external coherent signals present in the gravitational wave spectrum. The method works when the interference is present in many harmonics, as long as they remain…

General Relativity and Quantum Cosmology · Physics 2009-12-30 Alicia M. Sintes , Bernard F. Schutz

In this talk I describe MAGIC, an efficient approach to covariance estimation and signal reconstruction for Gaussian random fields (MAGIC Allows Global Inference of Covariance). It solves a long-standing problem in the field of cosmic…

Astrophysics · Physics 2014-10-13 Benjamin D. Wandelt

The late integrated Sachs-Wolfe (ISW) effect correlates the Cosmic Microwave Background (CMB) temperature anisotropies with foreground cosmic large-scale structures. As the correlation depends crucially on the growth history in the era of…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-16 Julian Adamek , Yann Rasera , Pier Stefano Corasaniti , Jean-Michel Alimi

Many multichannel systems use a linear filter to retrieve a signal of interest corrupted by noise whose statistics are partly unknown. The optimal filter in Gaussian noise requires knowledge of the noise covariance matrix $\Sigma$ and in…

Signal Processing · Electrical Eng. & Systems 2021-08-30 Olivier Besson

The detection of galactic binaries as sources of gravitational waves promises an unprecedented wealth of information about these systems, but also raises several challenges in signal processing. In particular the large number of expected…

General Relativity and Quantum Cosmology · Physics 2020-11-25 A. Blelly , J. Bobin , H. Moutarde

Peculiar velocities encode rich cosmological information, but their transverse components are hard to measure. Here, we present the first observations of a novel effect of transverse velocities: the dipole signatures that they imprint on…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-16 Yan-Chuan Cai , John A. Peacock , Anna de Graaff , Shadab Alam

In this work we propose a new matrix-free implementation of the Wiener sampler which is traditionally applied to high dimensional analysis when signal covariances are unknown. Specifically, the proposed method addresses the problem of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Jens Jasche , Guilhem Lavaux

The subject of this paper is an investigation of the nonlinear contributions to the spectrum of the integrated Sachs-Wolfe (iSW) effect. We derive the corrections to the iSW-auto spectrum and the iSW-tracer cross-spectrum consistently to…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-07 Bjoern Malte Schaefer , Angelos Fotios Kalovidouris , Lavinia Heisenberg

The analysis of absorption features along the line of sight to distant sources is an invaluable tool for observational cosmology, giving a direct insight into the physical and chemical state of the inter/circumgalactic medium. Such…

Instrumentation and Methods for Astrophysics · Physics 2023-05-18 Guido Cupani , Giorgio Calderone , Stefano Cristiani , Francesco Guarneri

Microwave imaging is commonly based on the solution of linearized inverse scattering problems by matched filtering algorithms, i.e., by applying the adjoint of the forward scattering operator to the observation data. A more rigorous…

Image and Video Processing · Electrical Eng. & Systems 2024-12-23 Matthias M. Saurer , Han Na , Marius Brinkmann , Thomas F. Eibert

We consider the problem of recovering of continuous multi-dimensional functions from the noisy observations over the regular grid. Our focus is at the adaptive estimation in the case when the function can be well recovered using a linear…

Statistics Theory · Mathematics 2009-03-06 Anatoli Iouditski , Arkadii S. Nemirovski

We present the second data release of the COSMOS Lyman-Alpha Mapping And Tomography Observations (CLAMATO) Survey conducted with the LRIS spectrograph on the Keck-I telescope. This project used Lyman-alpha forest absorption in the spectra…

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