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Orthogonal time frequency and space (OTFS) modulation is a promising technology that satisfies high Doppler requirements for future mobile systems. OTFS modulation encodes information symbols and pilot symbols into the two-dimensional (2D)…

Information Theory · Computer Science 2021-01-22 Noriyuki Hashimoto , Noboru Osawa , Kosuke Yamazaki , Shinsuke Ibi

Optical coherence tomography (OCT) is a prevalent, interferometric, high-resolution imaging method with broad biomedical applications. Nonetheless, OCT images suffer from an artifact, called speckle which degrades the image quality. Digital…

Simulated images are essential in algorithm development and instrument testing for optical telescopes. During real observations, images obtained by optical telescopes are affected by spatially variable point spread functions (PSFs), a…

Instrumentation and Methods for Astrophysics · Physics 2025-02-17 Zeyu Bai , Peng Jia , Jiameng Lv , Xiang Zhang , Wennan Xiang , Lin Nie

Frequency-dependent/hybrid approaches for stellar irradiation are of primary importance in numerical simulations of massive star formation. We seek to compare outflow and accretion mechanisms in star formation simulations. We investigate…

Instrumentation and Methods for Astrophysics · Physics 2020-03-11 R. Mignon-Risse , M. González , B. Commerçon , J. Rosdahl

With the availability of multi-object spectrometers and the designing \& running of some large scale sky surveys, we are obtaining massive spectra. Therefore, it becomes more and more important to deal with the massive spectral data…

Instrumentation and Methods for Astrophysics · Physics 2023-12-27 Xiangru Li , Yangtao Lin , Kaibin Qiu

We examine star-formation and dust properties for a sample of 660 galaxies at $1.37\leq z\leq 2.61$ in the MOSDEF survey by dividing them into groups with similarly-shaped spectral energy distributions (SEDs). For each group, we combine the…

Atomic diffusion with radiative levitation is a major transport process to consider to explain abundance anomalies in Am stars. Radiative accelerations vary from one species to another, yielding different abundance anomalies at the stellar…

Solar and Stellar Astrophysics · Physics 2024-11-20 Alain Hui-Bon-Hoa

Optical phase curves have become one of the common probes of exoplanetary atmospheres, but the information they encode has not been fully elucidated. Building on a diverse body of work, we upgrade the Flexible Modeling System (FMS) to…

Earth and Planetary Astrophysics · Physics 2016-03-09 Maria Oreshenko , Kevin Heng , Brice-Olivier Demory

Doppler spectroscopy has uncovered or confirmed all the known planets orbiting nearby stars. Two main techniques are used to obtain precision Doppler measurements at optical wavelengths. The first approach is the gas cell method, which…

Earth and Planetary Astrophysics · Physics 2015-06-04 Guillem Anglada-Escudé , R. Paul Butler

Recent and upcoming stabilized spectrographs are pushing the frontier for Doppler spectroscopy to detect and characterize low-mass planets. Specifications for these instruments are so impressive that intrinsic stellar variability is…

Instrumentation and Methods for Astrophysics · Physics 2020-05-05 Christian Gilbertson , Eric B. Ford , Xavier Dumusque

Recent advances in diffusion and flow-based generative models have demonstrated remarkable success in image restoration tasks, achieving superior perceptual quality compared to traditional deep learning approaches. However, these methods…

Computer Vision and Pattern Recognition · Computer Science 2026-03-20 Yuanzhi Zhu , Ruiqing Wang , Shilin Lu , Junnan Li , Hanshu Yan , Kai Zhang

Radiative transfer calculations are essential for modeling planetary atmospheres. However, standard methods are computationally demanding and impose accuracy-speed trade-offs. High computational costs force numerical simplifications in…

Earth and Planetary Astrophysics · Physics 2025-11-03 Isaac Malsky , Tiffany Kataria , Natasha E. Batalha , Matthew Graham

We present a real-space formulation and higher-order finite-difference implementation of periodic Orbital-free Density Functional Theory (OF-DFT). Specifically, utilizing a local reformulation of the electrostatic and kernel terms, we…

Computational Physics · Physics 2015-12-23 Swarnava Ghosh , Phanish Suryanarayana

In our first paper [2] we explained why the Zak-OTFS input-output (I/O) relation is predictable and non-fading when the delay and Doppler periods are greater than the effective channel delay and Doppler spreads, a condition which we refer…

Signal Processing · Electrical Eng. & Systems 2023-10-03 Saif Khan Mohammed , Ronny Hadani , Ananthanarayanan Chockalingam , Robert Calderbank

The differential Optical Transfer Function (dOTF) is a focal plane wavefront sensing method that uses a diversity in the pupil plane to generate two different focal plane images. The difference of their Fourier transforms recovers the…

Instrumentation and Methods for Astrophysics · Physics 2016-08-17 Keira J. Brooks , Laure Catala , Matthew A. Kenworthy , Steven M. Crawford , Johanan L. Codona

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

Space-based direct imaging provides prospects for detection and spectral characterization of exoplanets at optical and near-infrared wavelengths. Integral field spectrographs (IFS) have been historically baselined for these mission…

Earth and Planetary Astrophysics · Physics 2024-03-26 Jingwen Zhang , Michael Bottom , Eugene Serabyn

The study of stellar surfaces can reveal information about the chemical composition, interior structure, and magnetic properties of stars. It is also critical to the detection and characterization of extrasolar planets, in particular those…

Solar and Stellar Astrophysics · Physics 2021-10-14 Rodrigo Luger , Megan Bedell , Daniel Foreman-Mackey , Ian J. M. Crossfield , Lily L. Zhao , David W. Hogg

The formation of optical fluorescent lines in moving media has not yet been studied in detail, so this work represents a first step in investigating the fluorescence process in different types of macroscopic velocity fields: (a) accelerated…

Solar and Stellar Astrophysics · Physics 2024-09-04 Claude Bertout

Observations of stellar surfaces - except for the Sun - are hampered by their tiny angular extent, while observed spectral lines are smeared by averaging over the stellar surface, and by stellar rotation. Exoplanet transits can be used to…

Solar and Stellar Astrophysics · Physics 2016-12-07 Dainis Dravins , Hans-Günter Ludwig , Erik Dahlén , Hiva Pazira
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