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This study investigates a novel method for estimating two-dimensional velocities using coarse-grained imaging data, which is particularly relevant for applications in plasma diagnostics. The method utilizes measurements from three…

Plasma Physics · Physics 2025-01-28 J. M. Losada , O. E. Garcia

Galaxy peculiar velocities are excellent cosmological probes provided that biases inherent to their measurements are contained before any study. This paper proposes a new algorithm based on an object point process model whose probability…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-01 Jenny G. Sorce , Radu S. Stoica , Elmo Tempel

Time delay and velocity estimation has been a widely studied subject in the context of signal processing, with applications in many different fields of physics. The velocity of fluctuation structures is typically estimated as the distance…

Plasma Physics · Physics 2024-02-05 J. M. Losada , A. D. Helgeland , J. L. Terry , O. E. Garcia

We present a framework to compute non-Gaussian likelihoods for two-point correlation functions. The non-Gaussianity is most pronounced on large scales that will be well-measured by stage-IV weak-lensing surveys. We show how such a…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-09 Veronika Oehl , Tilman Tröster

The measurement of Doppler velocity shifts in spectra is a ubiquitous theme in astronomy, usually handled by computing the cross-correlation of the signals, and finding the location of its maximum. This paper addresses the problem of the…

Astrophysics · Physics 2008-11-26 Carlos Allende Prieto

We have investigated the scale-invariant solutions of the BBGKY equations for spatial correlation functions of cosmological density fluctuations and the mean relative peculiar velocity in the strongly nonlinear regime. It is found that the…

Astrophysics · Physics 2009-10-28 Taihei Yano , Naoteru Gouda

Weak gravitational lensing (WL) causes distortions of galaxy images and probes massive structures on large scales, allowing us to understand the late-time evolution of the Universe. One way to extract the cosmological information from WL is…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-14 Chieh-An Lin

We describe a new method of overcoming problems inherent in peculiar velocity surveys by using data compression as a filter with which to separate large-scale, linear flows from small-scale noise that biases the results systematically. We…

Astrophysics · Physics 2007-05-23 Hume A Feldman , Richard Watkins , Adrian Melott , Will Chambers

Context. In previous work, we developed a quasi-Gaussian approximation for the likelihood of correlation functions, which, in contrast to the usual Gaussian approach, incorporates fundamental mathematical constraints on correlation…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-21 Philipp Wilking , Randolf Röseler , Peter Schneider

Upcoming surveys such as \LSST{} and \Euclid{} will significantly improve the power of weak lensing as a cosmological probe. To maximise the information that can be extracted from these surveys, it is important to explore novel statistics…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-18 Christopher T. Davies , Marius Cautun , Benjamin Giblin , Baojiu Li , Joachim Harnois-Déraps , Yan-Chuan Cai

The local galaxy peculiar velocity field can be reconstructed from the surrounding distribution of large-scale structure and plays an important role in calibrating cosmic growth and expansion measurements. In this paper, we investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-20 Ryan J. Turner , Chris Blake

A model of soft frictionless disks in two dimensions at zero temperature is simulated with a shearing dynamics to study various kinds of asymmetries in sheared systems. We examine both single particle properties, the spatial velocity…

Soft Condensed Matter · Physics 2015-03-17 Peter Olsson

Estimating position and orientation change of a mobile platform from two consecutive point clouds provided by a high-resolution sensor is a key problem in autonomous navigation. In particular, scan matching algorithms aim to find the…

Signal Processing · Electrical Eng. & Systems 2021-06-09 Rico Mendrzik , Florian Meyer

The Virtual Image Correlation method applies for the measurement of silhouettes boundaries with sub-pixel precision. It consists in a correlation between the image of interest and a virtual image based on a parametrized curve. Thanks to a…

Computer Vision and Pattern Recognition · Computer Science 2020-09-11 M. L. M. François

We study the significance of non-Gaussianity in the likelihood of weak lensing shear two-point correlation functions, detecting significantly non-zero skewness and kurtosis in one-dimensional marginal distributions of shear two-point…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-11 Chien-Hao Lin , Joachim Harnois-Déraps , Tim Eifler , Taylor Pospisil , Rachel Mandelbaum , Ann B. Lee , Sukhdeep Singh

A promising method for measuring the cosmological parameter combination fsigma_8 is to compare observed peculiar velocities with peculiar velocities predicted from a galaxy density field using perturbation theory. We use N-body simulations…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-03 Amber M. Hollinger , Michael J. Hudson

Peculiar velocity surveys have non-uniform spatial distributions of tracers, so that the bulk flow estimated from them does not correspond to that of a simple volume such as a sphere. Thus bulk flow estimates are generally not strictly…

Astrophysics · Physics 2010-11-24 Richard Watkins , Hume A. Feldman , Michael J. Hudson

The peculiar motion of the host galaxies introduces bias in estimating cosmological parameters from supernova data. The coherent component of the peculiar motion is usually corrected for using velocity field reconstruction based on the…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-07 Ujjwal Upadhyay , Tarun Deep Saini , Shiv K. Sethi

Propagation of light in the universe with structure which amplify and modify the shape of distant galaxies, producing a correlation between nearby and distant density of galaxies, is a phenomena very important in cosmology for determining…

Astrophysics of Galaxies · Physics 2014-09-05 Leonardo Castañeda

We propose a simple and accurate method for computing analytically the mass correlation function for cold dark matter and scale-free models that fits N-body simulations over a range that extends from the linear to the strongly non-linear…

Astrophysics · Physics 2009-10-31 R. R. Caldwell , Roman Juszkiewicz , Paul J. Steinhardt , Francois Bouchet