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We present a direct comparison between two different techniques time-distance helioseismology and a local correlation tracking method for measuring mass flows in the solar photosphere and in a near-surface layer: We applied both methods to…

Astrophysics · Physics 2009-11-13 Michal Svanda , Junwei Zhao , Alexander G. Kosovichev

We measure the axisymmetric transport of magnetic flux on the Sun by cross-correlating narrow strips of data from line-of-sight magnetograms obtained at a 96-minute cadence by the MDI instrument on the ESA/NASA SOHO spacecraft and then…

Solar and Stellar Astrophysics · Physics 2011-03-30 David H. Hathaway , Lisa Rightmire

The 3D structure of solar wind and its evolution in time is needed for heliospheric modeling and interpretation of energetic neutral atoms observations. We present a model to retrieve the solar wind structure in heliolatitude and time using…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. M. Sokol , M. Bzowski , M. Tokumaru , K. Fujiki , D. J. McComas

The HMI project recently started processing the continuum intensity images following global helioseismology procedures similar to those used to process the velocity images. The spatial decomposition of these images has produced time series…

Solar and Stellar Astrophysics · Physics 2017-08-01 Sylvain G. Korzennik

Today's picture of the internal solar rotation rate profile results essentially from helioseismic analyses of frequency splittings of resonant acoustic waves. Here we present another, complementary estimation of the internal solar rotation…

Solar and Stellar Astrophysics · Physics 2020-02-17 Ariane Schad , Markus Roth

To address the problem of the low accuracy of transverse velocity field measurements for small targets in high-resolution solar images, we proposed a novel velocity field measurement method for high-resolution solar images based on PWCNet.…

Solar and Stellar Astrophysics · Physics 2023-05-29 Z. -H. Shang , S. -Y. Mu , K. -H Ji , Z. -P. Qiang

The velocity function derived from large scale surveys can be compared with the predictions of LCDM cosmology, by matching the measured rotation velocities Vrot of galaxies to the maximum circular velocity of dark matter (DM) halos Vmax.…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-09 Chris Brook , Francesco Shankar

We employ the DAVE (differential affine velocity estimator, Schuck 2005; 2006) tracking technique on a time series of MDI/1m high spatial resolution line- of-sight magnetograms to measure the photospheric flow velocity for three newly…

Solar and Stellar Astrophysics · Physics 2015-05-20 Lirong Tian , Pascal Démoulin , David Alexander , Chunming Zhu

Recently, Karoff and Kjeldsen (2008) presented evidence of strong correlation between the energy in the high-frequency part (5.3<\nu<8.3 mHz) of the acoustic spectrum of the Sun and the solar X-ray flux. They have used disk-integrated…

Solar and Stellar Astrophysics · Physics 2015-05-18 Brajesh Kumar , Savita Mathur , R. A. Garcia , P. Venkatakrishnan

The high-quality, full-disk helioseismic observations continuously collected by the spectrophotometer GOLF and the three photometers VIRGO/SPMs onboard the SoHO spacecraft for 17 years now (since April 11, 1996, apart from the SoHO…

Solar and Stellar Astrophysics · Physics 2013-09-18 D. Salabert , R. A. Garcia , A. Jimenez

Flows on the solar surface are linked to solar activity, and LCT is one of the standard techniques for capturing the dynamics of these processes by cross-correlating solar images. However, the link between contrast variations in successive…

Solar and Stellar Astrophysics · Physics 2015-06-16 M. Verma , M. Steffen , C. Denker

We report our first results on comparing the variations of the solar internal rotation with solar activity, as predicted by non-linear solar dynamo modelling, with helioseismic measurements using the SOHO MDI data.

Astrophysics · Physics 2007-05-23 S. Vorontsov , R. Tavakol , E. Covas , D. Moss

Solar activity is usually caused by the evolution of solar magnetic fields. Magnetic field parameters derived from photospheric vector magnetograms of solar active regions have been used to analyze and forecast eruptive events such as solar…

Solar and Stellar Astrophysics · Physics 2023-07-26 Haodi Jiang , Qin Li , Zhihang Hu , Nian Liu , Yasser Abduallah , Ju Jing , Genwei Zhang , Yan Xu , Wynne Hsu , Jason T. L. Wang , Haimin Wang

Gravitational 3-body interaction among binary stars and the supermassive black hole (SMBH) at the center of the Milky Way occasionally ejects a hypervelocity star (HVS) with a velocity of ~1000 km/s. Due to the ejection location, such a HVS…

Astrophysics of Galaxies · Physics 2018-12-19 Kohei Hattori , Monica Valluri , Norberto Castro

Large-scale plasma flows in the Sun's convection zone likely play a major role in solar dynamics on decadal timescales. In particular, quantifying meridional motions is a critical ingredient for understanding the solar cycle and the…

Solar and Stellar Astrophysics · Physics 2015-06-19 Shukur Kholikov , Alexander Serebryanskiy , Jason Jackiewicz

A new approach to estimating the velocity of the pole moving is considered. The method uses the model-calculated spatial distribution of the (vector) horizontal component \textbf{H} for a given year and its change relative to the closest…

Geophysics · Physics 2023-01-18 S. A. Ivanov , S. A. Merkuryev , I. M. Demina

The solar corona is host to a continuous flow of propagating disturbances (PD). These are continuous and ubiquitous across broad regions of the corona, including the quiet Sun. The aim of this paper is to present an improved, efficient…

Solar and Stellar Astrophysics · Physics 2022-08-31 Huw Morgan , Marianna Korsos

We present the results of a statistical analysis of the Doppler shifts and the asymmetry parameters of V profiles of the Fe I 630.25 nm line produced by 2D MHD simulations of solar granulation. The realism of the simulations tested using…

Solar and Stellar Astrophysics · Physics 2010-07-21 V. A. Sheminova

Systematic effects on HI and Halpha long-slit observations make a measurement of the inner slope of the dark matter density distribution difficult to determine. Halos with constant density cores and ones with r^-1 profiles both appear…

Astrophysics · Physics 2007-05-23 R. A. Swaters , M. A. W. Verheijen , M. A. Bershady , D. R. Andersen