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We present the identification of very low frequency g modes in the asymptotic regime and two important parameters that have long been waited for: the core rotation rate, and the asymptotic equidistant period spacing of these g modes. The…

Single-mode operation of coupled systems such as optical-fiber bundles, lattices of photonic waveguides, or laser arrays requires an efficient method to suppress unwanted super-modes. Here, we propose a systematic supersymmetry-based…

A new method to improve the accuracy and efficiency of characteristic mode (CM) decomposition for perfectly conducting bodies is presented. The method uses the expansion of the Green dyadic in spherical vector waves. This expansion is…

Computational Physics · Physics 2019-04-05 Doruk Tayli , Miloslav Capek , Lamyae Akrou , Vit Losenicky , Lukas Jelinek , Mats Gustafsson

We study temporal variations in the amplitudes and widths of high-degree acoustic modes in the quiet and active Sun by applying ring-diagram technique to the GONG+ and MDI Dopplergrams during the declining phase of cycle 23. The increase in…

Solar and Stellar Astrophysics · Physics 2015-05-20 Olga Burtseva , S. C. Tripathy , R. Howe , K. Jain , F. Hill , R. Bogart , M. C. Rabello-Soares

Context: Solar sectoral Rossby waves have only recently been unambiguously identified in Helioseimsic and Magnetic Imager (HMI) and Michelson Doppler Imager (MDI) maps of flows near the solar surface. So far this has not been done with the…

Solar and Stellar Astrophysics · Physics 2020-03-18 Chris S. Hanson , Laurent Gizon , Zhi-Chao Liang

Accurate determination of the rotation rate in the radiative zone of the sun from helioseismic observations requires rotational frequency splittings of exceptional quality as well as reliable inversion techniques. We present here inferences…

Astrophysics · Physics 2009-11-13 A. Eff-Darwich , S. G. Korzennik , S. J. Jimenez-Reyes , R. A. Garcia

Recent developments in instrumentation (e.g., in particular the Kepler and CoRoT satellites) provide a new opportunity to improve the models of stellar pulsations. Surface layers, rotation, and magnetic fields imprint erratic frequency…

Solar and Stellar Astrophysics · Physics 2015-06-04 M. Gruberbauer , D. B. Guenther , T. Kallinger

We present a comprehensive study of one method for measuring various parameters of global modes of oscillation of the Sun. Using velocity data taken by the Michelson Doppler Imager (MDI), we analyze spherical harmonic degrees l <= 300. Both…

Solar and Stellar Astrophysics · Physics 2015-11-18 Tim Larson , Jesper Schou

Short fixed-length inputs are the main bottleneck of deep learning methods in long time-series forecasting tasks. Prolonging input length causes overfitting, rapidly deteriorating accuracy. Our research indicates that the overfitting is a…

Machine Learning · Computer Science 2025-09-05 Chao Ma , Yikai Hou , Xiang Li , Yinggang Sun , Haining Yu

Time-series forecasting is crucial for numerous real-world applications including weather prediction and financial market modeling. While temporal-domain methods remain prevalent, frequency-domain approaches can effectively capture…

Machine Learning · Computer Science 2025-08-05 Zhixuan Li , Naipeng Chen , Seonghwa Choi , Sanghoon Lee , Weisi Lin

We used the m-averaged spectrum technique ("collapsogram") to extract the low-frequency solar p-mode parameters of low- and intermediate-angular degrees (l \leq 35) in long time series of GONG and MDI observations. Rotational splittings and…

Astrophysics · Physics 2008-11-12 D. Salabert , A. Eff-Darwich , R. Howe , S. G. Korzennik

We propose a probabilistic framework for performing simultaneous estimation of source structure and fringe-fitting parameters in Very Long Baseline Interferometry (VLBI) observations. As a first step, we demonstrate this technique through…

Instrumentation and Methods for Astrophysics · Physics 2020-06-10 Iniyan Natarajan , Roger Deane , Ilse van Bemmel , Huib Jan van Langevelde , Des Small , Mark Kettenis , Zsolt Paragi , Oleg Smirnov , Arpad Szomoru

Using a time series model to mimic an observed time series has a long history. However, with regard to this objective, conventional estimation methods for discrete-time dynamical models are frequently found to be wanting. In fact, they are…

Statistics Theory · Mathematics 2015-03-19 Yingcun Xia , Howell Tong

Time series play a fundamental role in many domains, capturing a plethora of information about the underlying data-generating processes. When a process generates multiple synchronized signals we are faced with multidimensional time series.…

Data Structures and Algorithms · Computer Science 2026-03-20 Matteo Ceccarello , Francesco Pio Monaco , Francesco Silvestri

The decomposition of the cosmic shear field into E- and B-mode is an important diagnostic in weak gravitational lensing. However, commonly used techniques to perform this separation suffer from mode-mixing on very small or very large…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Liping Fu , Martin Kilbinger

At high frequencies beyond the acoustic cut-off, a peak-like structure is visible in the solar power spectrum. Known as the pseudo-modes, their frequencies have been shown to vary in anti-phase with solar magnetic activity. In this work, we…

Solar and Stellar Astrophysics · Physics 2024-09-06 Laura Jade Millson , Anne-Marie Broomhall , Tishtrya Mehta

Guided mode resonance (GMR), the resonant coupling of free-space light into leaky waveguide modes, is traditionally achieved with periodic patterned structures. However, this approach makes its key properties such as quality factor…

Optics · Physics 2026-04-03 Youxiu Yu , Xiaofeng Xu , Yang Long , Gui-Geng Liu , Dongliang Gao , Xiao Lin , Hao Hu

We present a maximum likelihood method for fitting two-dimensional model distributions to stellar data in colour-magnitude space. This allows one to include (for example) binary stars in an isochronal population. The method also allows one…

Astrophysics · Physics 2009-11-11 Tim Naylor , Rob Jeffries

This paper provides an accurate theoretical defect energy database for pure and Bi-containing III-V (III-V:Bi) materials and investigates efficient methods for high-throughput defect calculations based on corrections of results obtained…

Materials Science · Physics 2021-12-07 Maciej P. Polak , Robert Kudrawiec , Ryan Jacobs , Izabela Szlufarska , Dane Morgan

Dynamic mode decomposition (DMD) provides a principled approach to extract physically interpretable spatial modes from time-resolved flow field data, along with a linear model for how the amplitudes of these modes evolve in time. Recently,…

Fluid Dynamics · Physics 2020-07-29 Aditya G. Nair , Benjamin Strom , Bingni W. Brunton , Steven L. Brunton