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The multivariate tool of Principal Component Analysis (PCA) is applied to 23 fields in the FCRAO CO Survey of the Outer Galaxy. PCA enables the identification of line profile differences which are assumed to be generated from fluctuations…

Astrophysics · Physics 2009-11-07 Christopher M. Brunt , Mark H. Heyer

The Fourier Transform method is a popular tool to derive the rotational velocities of stars from their spectral line profiles. However, its domain of validity does not include line-profile variables with time-dependent profiles. We…

Solar and Stellar Astrophysics · Physics 2014-10-01 C. Aerts , S. Simon-Diaz , P. J. Groot , P. Degroote

In this paper we discuss recent applications of the Smoothed Particle Hydrodynamics (SPH) method to the simulation of supersonic turbulence in the interstellar medium, as well as giving an update on recent algorithmic developments in…

Instrumentation and Methods for Astrophysics · Physics 2010-02-26 Daniel J. Price , Christoph Federrath

We study the cascading of fast MHD modes in magnetically dominated plasma by performing one-dimensional (1D) dynamical simulations. We find that the cascading becomes more efficient as an angle between wave vector and underlying magnetic…

Astrophysics · Physics 2011-02-11 T. K. Suzuki , A. Lazarian , A. Beresnyak

Various methods for leveraging turbulent fluctuation measurements from fusion plasma experiments are introduced, along with selected application examples. These can be categorized into spectral methods, statistical methods, and physics…

Plasma Physics · Physics 2025-10-27 Minjun J. Choi

We propose a new approach to comparing simulated observations that enables us to determine the significance of the underlying physical effects. We utilize the methodology of experimental design, a subfield of statistical analysis, to…

Astrophysics of Galaxies · Physics 2015-06-18 Miayan Yeremi , Mallory Flynn , Stella Offner , Jason Loeppky , Erik Rosolowsky

The problem of determination of the orbital velocity of an astrometric satellite from its own observational data is studied. It is well known that data processing of microarcsecond-level astrometric observations imposes very stringent…

Astrophysics · Physics 2008-02-11 Alexey G. Butkevich , Sergei A. Klioner

Virtual Diagnostic (VD) is a computational tool based on deep learning that can be used to predict a diagnostic output. VDs are especially useful in systems where measuring the output is invasive, limited, costly or runs the risk of…

Accelerator Physics · Physics 2021-08-04 Owen Convery , Lewis Smith , Yarin Gal , Adi Hanuka

An accelerated analysis method for non-uniform metasurfaces in FDTD is presented for the first time. The non-uniform metasurfaces are modeled by a distribution of susceptibilities, homogenized parameters. Those susceptibilities are…

Computational Physics · Physics 2018-09-18 Xiao Jia , Maokun Li , Shenheng Xu , Christophe Caloz , Fan Yang

We assemble a homogeneous database of precise and consistent determinations of effective temperature, surface gravity, projected rotational rate, and macro- and micro-turbulent velocities for over 1800 Galactic stars spanning spectral types…

Solar and Stellar Astrophysics · Physics 2025-10-01 N. Markova , M. Cantiello , L. Grassitelli

We propose and validate a novel experimental technique to measure two-point statistics of turbulent flows. It consists in spreading rigid fibers in the flow and tracking their position and orientation in time and therefore been named…

The atomic-to-molecular (HI-to-H$_2$) transition in photodissociation regions (PDRs) has been investigated over the last several decades through analytic and numerical modeling. However, classical PDR models typically assume uniform density…

Astrophysics of Galaxies · Physics 2021-01-06 Yue Hu , A. Lazarian , Shmuel Bialy

We introduce the first comprehensive approach to determine the uncertainty in volumetric Particle Tracking Velocimetry (PTV) measurements. Volumetric PTV is a state-of-the-art non-invasive flow measurement technique, which measures the…

Fluid Dynamics · Physics 2022-10-19 Sayantan Bhattacharya , Pavlos P. Vlachos

A review of various exactly solvable models on the determination of the energy spectra $E (k) $ of 3D-velocity field, induced by chaotic vortex lines is proposed. This problem is closely related to the sacramental question whether a chaotic…

Statistical Mechanics · Physics 2015-06-05 Sergey K. Nemirovskii

We discuss a recent experiment in which the spectrum of the vortex line density fluctuations has been measured in superfluid turbulence. The observed frequency dependence of the spectrum, $f^{-5/3}$, disagrees with classical vorticity…

Other Condensed Matter · Physics 2012-02-14 Philippe-Emmanuel P. -E. Roche , Carlo F. Barenghi

Measurements of intensity and polarization of diffuse Galactic synchrotron emission as well as starlight polarization reveal power law spectra of fluctuations. We show that these fluctuations can arise from magnetohydrodynamic (MHD)…

Astrophysics · Physics 2016-08-30 Jungyeon Cho , A. Lazarian

We have designed and built a new type of CCD that we call an orthogonal transfer CCD (OTCCD), which permits parallel clocking horizontally as well as vertically. The device has been used successfully to remove image motion caused by…

Astrophysics · Physics 2007-05-23 John L. Tonry , Barry E. Burke , Paul L. Schechter

Analyses of peculiar velocity surveys face several challenges, including low signal--to--noise in individual velocity measurements and the presence of small--scale, nonlinear flows. This is the second in a series of papers in which we…

Astrophysics · Physics 2009-11-07 Hume A. Feldman , Richard Watkins , Adrian L. Melott , Scott W. Chambers

Non-parametric change-point detection in streaming time series data is a long-standing challenge in signal processing. Recent advancements in statistics and machine learning have increasingly addressed this problem for data residing on…

Machine Learning · Computer Science 2025-08-26 Xiuheng Wang , Ricardo Borsoi , Arnaud Breloy , Cédric Richard

The majority of studies on multi-scale vortex motions employ a two-dimensional geometry by using a variety of observational and numerical data. This approach limits the understanding the nature of physical processes responsible for vortex…

Fluid Dynamics · Physics 2022-03-30 Yasir Aljohani , Viktor Fedun , Istvan Ballai , Suzana S. A. Silva , Sergiy Shelyag , Gary Verth
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