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It is commonplace in cosmology to analyze fields projected onto the celestial sphere, and in particular density fields that are defined by a set of points e.g. galaxies. When performing an harmonic-space analysis of such data (e.g. an…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-02 Antón Baleato Lizancos , Martin White

Broadband time-ordered data obtained from telescopes with a wavelength-dependent, asymmetric beam pattern can be used to extract maps at multiple wavelengths from a single scan. This technique is especially useful when collecting data on…

Instrumentation and Methods for Astrophysics · Physics 2023-06-06 Brianna Cantrall , Solomon Quinn , Emory F. Bunn

A periodizing scheme and the method of fundamental solutions are used to solve acoustic wave scattering from doubly-periodic three-dimensional multilayered media. A scattered wave in a unit cell is represented by the sum of the near and…

Numerical Analysis · Mathematics 2019-06-26 Min Hyung Cho

There is enormous potential to advance cosmology from statistical characterizations of cosmic microwave background sky maps. The angular power spectrum of the microwave anisotropy is a particularly important statistic. Existing algorithms…

Astrophysics · Physics 2009-10-30 Siang Peng Oh , David N. Spergel , Gary Hinshaw

We consider a search for the anisotropic stochastic gravitational-wave background (SGWB) that decomposes the sky map into its spherical harmonics components in order to obtain estimators of the angular power spectrum. Such a search often…

General Relativity and Quantum Cosmology · Physics 2026-04-21 Erik Floden , Alex Granados , Vuk Mandic

The Cosmological Principle states that the universe is statistically isotropic and homogeneous on large length scales, typically $\gtrsim 70$Mpc. A detection of significant deviation would help us falsify the simplest models of inflation.…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-26 Bhuwan Joshi , Rahul Kothari

We apply the Gabor transform methodology proposed in (Hansen et al. 2002, 2003) to the WMAP data in order to test the statistical properties of the CMB fluctuation field and specifically to evaluate the fundamental assumption of…

Astrophysics · Physics 2009-05-29 F. K. Hansen , A. J. Banday , K. M. Gorski

The Quadratic Maximum Likelihood estimator can be used to reconstruct the Cosmic Microwave Background (CMB) power spectra with minimal error bars. Still, it requires an accurate estimate of the datasets noise covariance matrix in order to…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-28 S. Vanneste , S. Henrot-Versillé , T. Louis , M. Tristram

We set up a general framework to describe $\pi\pi$ scattering below 1 GeV based on chiral low-energy expansion with possible spin-0 and 1 resonances. Partial wave amplitudes are obtained with the $N/D$ method, which satisfy unitarity,…

High Energy Physics - Phenomenology · Physics 2008-11-26 Keiji Igi , Ken-ichi Hikasa

In this paper we provide further spectral analysis of the general asymptotic scattering resonances formula of small high contrast 3D dielectrics of arbitrary shape, initially derived to a first order approximation. To investigate the…

Mathematical Physics · Physics 2022-04-22 Taoufik Meklachi , Kevin Li , Brian Adams

Identifying frequencies with low signal-to-noise ratios in time series of stellar photometry and spectroscopy, and measuring their amplitude ratios and peak widths accurately, are critical goals for asteroseismology. These are also…

Data Analysis, Statistics and Probability · Physics 2010-06-29 P. Reegen

In this paper we propose a technique for spectral envelope estimation using maximum values in the sub-bands of Fourier magnitude spectrum (MSASB). Most other methods in the literature parametrize spectral envelope in cepstral domain such as…

Orbital solutions for binary or multiple stellar systems that combine astrometry (e.g., position angles and angular separations) with spectroscopy (radial velocities) have important advantages over astrometric-only or spectroscopic-only…

Astrophysics · Physics 2007-05-23 Guillermo Torres

This article investigates the problem of estimating stellar atmospheric parameters from spectra. Feature extraction is a key procedure in estimating stellar parameters automatically. We propose a scheme for spectral feature extraction and…

Instrumentation and Methods for Astrophysics · Physics 2015-08-04 Tan Yang , Xiangru Li

This article addresses the measurement of the power spectrum of red noise processes at the lowest frequencies, where the minimum acquisition time is so long that it is impossible to average on a sequence of data record. Therefore, averaging…

Data Analysis, Statistics and Probability · Physics 2022-06-30 Antoine Baudiquez , Éric Lantz , Enrico Rubiola , François Vernotte

There has been much recent interest in studying anisotropies in the astrophysical gravitational-wave (GW) background, as these could provide us with interesting new information about galaxy clustering and large-scale structure. However,…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-29 Alexander C. Jenkins , Joseph D. Romano , Mairi Sakellariadou

Multi-index models provide a popular framework to investigate the learnability of functions with low-dimensional structure and, also due to their connections with neural networks, they have been object of recent intensive study. In this…

Machine Learning · Statistics 2025-06-11 Filip Kovačević , Yihan Zhang , Marco Mondelli

This paper presents a new Bayesian spectral unmixing algorithm to analyse remote scenes sensed via sparse multispectral Lidar measurements. To a first approximation, in the presence of a target, each Lidar waveform consists of a main peak,…

Thomson's multitaper method estimates the power spectrum of a signal from $N$ equally spaced samples by averaging $K$ tapered periodograms. Discrete prolate spheroidal sequences (DPSS) are used as tapers since they provide excellent…

Signal Processing · Electrical Eng. & Systems 2021-03-23 Santhosh Karnik , Justin Romberg , Mark A. Davenport

Understanding the impact of spectral coverage on parameter recovery is critical for accurate interpretation of blazar spectra. In this study, we examine how the data coverage influences the reliability of parameter estimation within the…

High Energy Astrophysical Phenomena · Physics 2025-11-26 N. Sahakyan , D. Bégué , P. Giommi , H. Dereli-Bégué , Asaf Pe'er
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