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The present paper is focused on the problem of recovering the Radon-Nikodym derivative under the big data assumption. To address the above problem, we design an algorithm that is a combination of the Nystr\"om subsampling and the standard…

Numerical Analysis · Mathematics 2025-11-13 Hanna Myleiko , Sergei Solodky

Learning convolution kernels in operators from data arises in numerous applications and represents an ill-posed inverse problem of broad interest. With scant prior information, kernel methods offer a natural nonparametric approach with…

Numerical Analysis · Mathematics 2025-07-17 Haibo Li , Fei Lu

We introduce a new method to infer the posterior distribution for planet occurrence rates from radial-velocity (RV) observations. The approach combines posterior samples from the analysis of individual RV datasets of several stars, using…

Earth and Planetary Astrophysics · Physics 2026-01-14 J. P. Faria , J. -B. Delisle , D. Ségransan

Radial velocity measurements can be used to constrain the dynamical state of a stellar cluster. However, for clusters with velocity dispersions smaller than a few km/s the observed radial velocity distribution tends to be dominated by the…

Solar and Stellar Astrophysics · Physics 2015-06-11 Michiel Cottaar , Michael R. Meyer , Richard J. Parker

A novel algorithm was recently presented to utilize emerging time dependent probability density data to extract molecular potential energy surfaces. This paper builds on the previous work and seeks to enhance the capabilities of the…

Chemical Physics · Physics 2009-11-07 Lukas Kurtz , Herschel Rabitz , Regina de Vivie-Riedle

Meshless collocation with multiquadric radial basis functions (MQ-RBFs) delivers high accuracy for the three-dimensional Helmholtz equation but produces dense, severely ill-conditioned linear systems. We develop and evaluate three…

Numerical Analysis · Mathematics 2025-11-14 Mohamed El Guide , Khalide Jbilou , Kamal Lachhab , Driss Ouazar

Some formulae are presented for finding two-integral distribution functions (DFs) which depends only on the two classical integrals of the energy and the magnitude of the angular momentum with respect to the axis of symmetry for stellar…

Mathematical Physics · Physics 2007-08-28 Zhenglu Jiang , Leonid Ossipkov

Pixel-space full spectrum fitting exploiting non-linear $\chi^2$ minimization became a \emph{de facto} standard way of deriving internal kinematics from absorption line spectra of galaxies and star clusters. However, reliable estimation of…

Instrumentation and Methods for Astrophysics · Physics 2020-04-29 Igor V. Chilingarian , Kirill A. Grishin

This paper introduces a new strategy for setting the regularization parameter when solving large-scale discrete ill-posed linear problems by means of the Arnoldi-Tikhonov method. This new rule is essentially based on the discrepancy…

Numerical Analysis · Mathematics 2013-07-02 Silvia Gazzola , Paolo Novati , Maria Rosaria Russo

This paper is devoted to the study of the local rapid exponential stabilization problem for a controlled Kuramoto-Sivashinsky equation on a bounded interval. We build a feedback control law to force the solution of the closed-loop system to…

Optimization and Control · Mathematics 2015-01-12 Jean-Michel Coron , Qi Lu

Variability in the light curves of spotted, rotating stars is often non-sinusoidal and quasi-periodic --- spots move on the stellar surface and have finite lifetimes, causing stellar flux variations to slowly shift in phase. A strictly…

Solar and Stellar Astrophysics · Physics 2017-12-27 Ruth Angus , Timothy Morton , Suzanne Aigrain , Daniel Foreman-Mackey , Vinesh Rajpaul

Choosing the regularization parameter for inverse problems is of major importance for the performance of the regularization method. We will introduce a fast version of the Lepskij balancing principle and show that it is a valid parameter…

Numerical Analysis · Mathematics 2010-08-04 Frank Bauer

In this paper, we consider the nonlinear ill-posed inverse problem with noisy data in the statistical learning setting. The Tikhonov regularization scheme in Hilbert scales is considered to reconstruct the estimator from the random noisy…

Statistics Theory · Mathematics 2024-04-09 Abhishake Rastogi

When studying massive stars and their life cycles, rotation plays a key role. Hence, understanding the rotation of these stars is crucial when determining their properties, or for constraining evolutionary models. We examine the reliability…

Solar and Stellar Astrophysics · Physics 2026-05-21 L. Delbroek , J. O. Sundqvist , F. Backs , T. Ceulemans , D. Debnath , P. Schillemans

We introduce two new methods to obtain reliable velocity field statistics from N-body simulations, or indeed from any general density and velocity fluctuation field sampled by discrete points. These methods, the {\it Voronoi tessellation…

Astrophysics · Physics 2017-03-08 Francis Bernardeau , Rien van de Weygaert

The Tremaine-Weinberg (TW) method and its variations provide the most direct means to measure the pattern speeds of galactic bars. We establish a unifying framework by deriving an integral form of the continuity equation over an arbitrary…

Astrophysics of Galaxies · Physics 2026-04-10 Hangci Du , Yougang Wang , Junqiang Ge , Rui Guo

The structure and star formation activity of a molecular cloud are fundamentally linked to its internal turbulence. However, accurately measuring the turbulent velocity dispersion is challenging due to projection effects and observational…

Astrophysics of Galaxies · Physics 2021-12-22 Madeleine Stewart , Christoph Federrath

We introduce a generalization of Obukhov's model [A.M. Obukhov, Adv. Geophys. 6, 113 (1959)] for the description of the joint position-velocity statistics of a single fluid particle in fully developed turbulence. In the presented model the…

Fluid Dynamics · Physics 2009-11-11 A. Baule , R. Friedrich

We show that the observational data recently provided by Giovanelli et al. (1996 a, b) and discussed by Bahcall and Oh (1996) concerning the velocity distribution of clusters of galaxies can be naturally fitted by a statistical distribution…

Astrophysics · Physics 2007-05-23 A. Lavagno , G. Kaniadakis , M. Rego-Monteiro , P. Quarati , C. Tsallis

This paper describes the treatment of systematic uncertainties in a Likelihood formalism. RooUnfold, which includes most of the unfolding methods that are commonly used in particle physics, is used to compare a newly implemented method…

High Energy Physics - Experiment · Physics 2025-10-20 Lydia Brenner , Carsten Burgard , Vincent Alexander Croft