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Related papers: Accretion Stream Mapping

200 papers

Field-channelled accretion flows occur in a variety of astrophysical objects, including T Tauri stars,magnetic cataclysmic variables and X-ray pulsars. We consider a curvilinear coordinate system and derive a general hydrodynamic…

Astrophysics · Physics 2009-11-10 Joao B. G. Canalle , Curtis J. Saxton , Kinwah Wu , Mark Cropper , Gavin Ramsay

We introduce a new mathematical tool (a direction-dependent probe) to analyse the randomness of purported isotropic Gaussian random fields on the sphere. We apply the probe to assess the full-sky cosmic microwave background (CMB)…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-29 J. Hamann , Q. T. Le Gia , I. H. Sloan , Y. G. Wang , R. S. Womersley

In the present study, two schemes named face discernment and flux correction are proposed to achieve single-phase transportation of free charge in multiphase electrohydrodynamic(EHD) problems. Many EHD phenomena occur between air and…

Fluid Dynamics · Physics 2022-07-19 Qiang Liu , Jie Zhang , Jian Wu

We use an Autoregressive (AR) approach combined with a Maximum Entropy Method (MEM) to estimate radial surface currents from coastal High-Frequency Radar (HFR) complex voltage time series. The performances of this combined AR-MEM model are…

Signal Processing · Electrical Eng. & Systems 2020-12-22 Baptiste Domps , Dylan Dumas , Charles-Antoine Guérin , Julien Marmain

We discuss spatially and temporally adaptive implicit-explicit (IMEX) methods for parallel simulations of three-dimensional fluid streamer discharges in atmospheric air. We examine strategies for advancing the fluid equations and elliptic…

Plasma Physics · Physics 2019-01-25 Robert Marskar

We present synthetic Doppler maps of gaseous flows in binary IP Peg based on the results of 3D gasdynamical simulations. Using of gasdynamical calculations alongside with the Doppler tomography technique permits us to identify the main…

Boundary detection of irregular and translucent objects is an important problem with applications in medical imaging, environmental monitoring and manufacturing, where many of these applications are plagued with scarce labeled data and low…

Computer Vision and Pattern Recognition · Computer Science 2026-04-14 Fei Yu Guan , Ian Keefe , Sophie Wilkinson , Daniel D. B. Perrakis , Steven Waslander

We calibrated a technique to measure dust attenuation in star-forming galaxies. The technique utilizes the stellar-wind lines in Wolf-Rayet stars, which are widely observed in galaxy spectra. The He II 1640 and 4686 features are…

Astrophysics of Galaxies · Physics 2019-11-06 Claus Leitherer , Janice C. Lee , Andreas Faisst

We present DualMat, a novel dual-path diffusion framework for estimating Physically Based Rendering (PBR) materials from single images under complex lighting conditions. Our approach operates in two distinct latent spaces: an…

Computer Vision and Pattern Recognition · Computer Science 2025-08-08 Yifeng Huang , Zhang Chen , Yi Xu , Minh Hoai , Zhong Li

We study AGN emission line profiles combining an improved version of the accretion disc-wind model of Murray & Chiang with the magneto-hydrodynamic model of Emmering et al. (1992). Here we extend our previous work to consider central…

Astrophysics of Galaxies · Physics 2016-11-04 L. S. Chajet , P. B. Hall

We introduce a new algorithm to solve a regularized spatial-spectral image estimation problem. Our approach is based on the linearized alternating directions method of multipliers (LADMM), which is a variation of the popular ADMM algorithm.…

Signal Processing · Electrical Eng. & Systems 2025-02-25 Yunsong Liu , Debdut Mandal , Congyu Liao , Kawin Setsompop , Justin P. Haldar

Low-resolution spectra from 3000-9000 AA of young low-mass stars and brown dwarfs were obtained with LRIS on Keck I. The excess UV and optical emission arising in the Balmer and Paschen continua yields mass accretion rates ranging from…

Astrophysics · Physics 2009-06-23 Gregory J. Herczeg , Lynne A. Hillenbrand

We have followed up on our observations of the ~ 40-Myr, and still accreting, PMC Delorme 1 (AB)b. We used high-resolution spectroscopy to characterise the accretion process further by accessing the wealth of emission lines in the near-UV.…

Earth and Planetary Astrophysics · Physics 2023-03-27 Simon C. Ringqvist , Gayathri Viswanath , Yuhiko Aoyama , Markus Janson , Gabriel-Dominique Marleau , Alexis Brandeker

High resolution spectra are necessary to distinguish and correctly measure the Balmer emission lines due to the presence of strong metal and Balmer absorption features in the stellar continuum. This accurate measurement is necessary for use…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 Brent Groves , Jarle Brinchmann , Carl Jakob Walcher

A two dimensional numerical model in the axisymmetric approximation that describes the flow structure in the magnetosphere of the white dwarf in the EX Hya system has been developed. Results of simulations show that the accretion in EX Hya…

Solar and Stellar Astrophysics · Physics 2019-12-23 P. B. Isakova , A. G. Zhilkin , D. V. Bisikalo , A. N. Semena , M. G. Revnivtsev

Wavefront shaping enables targeted delivery of coherent light into random-scattering media, such as biological tissue, by constructive interference of scattered waves. However, broadband waves have short coherence times, weakening the…

The dimer method is a Hessian-free algorithm for computing saddle points. We augment the method with a linesearch mechanism for automatic step size selection as well as preconditioning capabilities. We prove local linear convergence. A…

Optimization and Control · Mathematics 2014-07-30 N. Gould , C. Ortner , D. Packwood

We present a new method, the Coupled Escape Probability (CEP), for exact calculation of line emission from multi-level systems, solving only algebraic equations for the level populations. The CEP formulation of the classical two-level…

Astrophysics · Physics 2009-11-13 Moshe Elitzur , Andres Asensio Ramos

Aims. We present a new list of thorium and argon emission lines in the visible obtained by analyzing high-resolution (R=110,000) spectra of a ThAr hollow cathode lamp. The aim of this new line list is to allow significant improvements in…

Astrophysics · Physics 2009-11-13 C. Lovis , F. Pepe

In this paper we study the joint determination of source and background flux for point sources as observed by digital array detectors. We explicitly compute the two-dimensional Cram\'er-Rao absolute lower bound (CRLB) as well as the…

Instrumentation and Methods for Astrophysics · Physics 2023-11-22 Mario L. Vicuña , Jorge F. Silva , Rene A. Mendez , Marcos E. Orchard , Sebastian Espinosa , Jeremy Tregloan-Reed