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Next-generation solar spectrographs increasingly record dense wavelength windows in which tens to hundreds of spectral lines are sampled at each spatial location and time step. This expands the scope for multi-line, multi-height diagnostics…

New improvements in the measurement of both the optical solar spectrum and laboratory wavelengths for lines of neutral iron are combined to extract central wavelength shifts for 1446 lines observed in the Sun. This provides the largest…

Astrophysics · Physics 2009-10-30 C. Allende Prieto , R. J. Garcia Lopez

Birmingham Solar Oscillations Network (BiSON) instruments use resonant scattering spectrometers to make unresolved Doppler velocity observations of the Sun. Unresolved measurements are not homogenous across the solar disc and so the…

Solar and Stellar Astrophysics · Physics 2015-05-13 A. M. Broomhall , W. J. Chaplin , Y. Elsworth , R. New

With an aim to examine how much information of solar rotation can be obtained purely spectroscopically by observing the sun-as-a-star during the 2012 May 21 eclipse at Okayama Astrophysical Observatory, we studied the variation of radial…

Solar and Stellar Astrophysics · Physics 2015-06-23 Yoichi Takeda , Osamu Ohshima , Eiji Kambe , Hiroyuki Toda , Hisashi Koyano , Bun'ei Sato , Yasuhisa Nakamura , Norio Narita , Takashi Sekii

The center-to-limb variations (CLV) of transition region line Gaussian fit parameters in solar plage are reported for the first time. The Si iv 1402.77 A line observed by Interface Region Imaging Spectrograph (IRIS) is used. The spectral…

Solar and Stellar Astrophysics · Physics 2024-11-05 Pradeep Kayshap , Peter R. Young

The measurements of the Doppler shifts of the Fraunhofer lines, scattered by the dust grains in the solar F-corona, provides the insight on the velocity field of the dust and hence on its origin. We report on such measurements obtained…

Solar and Stellar Astrophysics · Physics 2010-03-16 L. I. Shestakova , A. Chalabaev , B. I. Demchenko , F. K. Rspaev

The determination of solar wind outflow velocity is fundamental in order to probe the mechanisms of wind acceleration in the corona. We aim to study, via the Doppler dimming technique, the effects that the chromospheric Ly{\alpha} line…

Spatially averaged (> 50'') EUV spectral lines in the transition region of solar quiet regions are known to be redshifted. Because the mechanism underlying this phenomenon is unclear, we require additional physical information on the lower…

Solar and Stellar Astrophysics · Physics 2016-01-13 N. Kitagawa , H. Hara , T. Yokoyama

On March 20, 2015, we obtained 159 spectra of the Sun as a star with the solar telescope and the FTS at the Institut f\"ur Astrophysik G\"ottingen, 76 spectra were taken during partial solar eclipse. We obtained RVs using $I_2$ as…

Solar and Stellar Astrophysics · Physics 2016-10-26 Ansgar Reiners , Ulrike Lemke , Florian Bauer , Benjamin Beeck , Philipp Huke

The WISPR imager on Parker Solar Probe provides a unique view the young solar wind, flying through solar wind structures at high speed. It is of interest to use WISPR image sequences to measure the velocity of both large features (such as…

Solar and Stellar Astrophysics · Physics 2025-02-05 Samuel J. Van Kooten , Craig E. Deforest , Guillermo Stenborg , Kenny N. Kenny

The solar tachocline, located at the interface between the latitude-dependent rotation of the convection zone and the rigid radiative interior, presents high gradients of angular velocity which are of particular interest for the models of…

Astrophysics · Physics 2013-08-01 T. Corbard , S. J. Jiménez-Reyes , S. Tomczyk , M. Dikpati , P. Gilman

For many years various asymmetrical profiles of different spectral lines emitted from solar flares have been frequently observed. These asymmetries or line shifts are caused predominantly by vertical mass motions in flaring layers and they…

Astrophysics · Physics 2007-05-23 A. Berlicki

We present a method for determining surface flows from solar images based upon optical flow techniques. We apply the method to sets of images obtained by a variety of solar imagers to assess its performance. The {\tt opflow3d} procedure is…

Computer Vision and Pattern Recognition · Computer Science 2015-12-02 Neal Hurlburt , Steve Jaffey

The aim of this work is to give new observational constraints on solar surface flows by determining the horizontal scale dependence of the velocity and intensity fields, as represented by their power spectra, and to offer some theoretical…

Solar and Stellar Astrophysics · Physics 2015-05-14 M. Rieutord , T. Roudier , F. Rincon , J. -M. Malherbe , N. Meunier , T. Berger , Z. Frank

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

Correction due to finite speed of light is among the most inconsistent ones in absolute gravimetry. Formulas reported by different authors yield corrections scattered up to 8 $\mu$Gal with no obvious reasons. The problem, though noted…

Instrumentation and Detectors · Physics 2015-03-17 V D Nagornyi , Y M Zanimonskiy , Y Y Zanimonskiy

Studying the properties of the solar convection using high-resolution spectropolarimetry began in the early 90's with the focus on observations in the visible wavelength regions. Its extension to the infrared (IR) remains largely…

Solar and Stellar Astrophysics · Physics 2019-10-16 Ivan Milic , Smitha Narayanamurthy , Andreas Lagg

The center-to-limb variations (CLVs) of photospheric and chromospheric spectral lines were obtained in 2025 July and August using drift scans from the echelle spectrograph of the 0.7 m Vacuum Tower Telescope at the Observatorio del Teide…

Solar and Stellar Astrophysics · Physics 2025-11-10 Meetu Verma , Carsten Denker , Alexander G. M. Pietrow , Robert Kamlah , Dominique J. M. Petit dit de la Roche

We analyze in situ measurements of solar wind velocity obtained by Advanced Composition Explorer (ACE) spacecraft and Helios spacecraft during the years 1998-2012 and 1975-1983 respectively. The data belong to mainly solar cycle 23…

Solar and Stellar Astrophysics · Physics 2013-06-11 Vinita Suyal , Awadhesh Prasad , Harinder P. Singh

Ring diagram analysis of solar oscillation power spectra obtained from MDI data is carried out to study the velocity fields in the outer part of the solar convection zone. The three dimensional power spectra are fitted to a model which has…

Astrophysics · Physics 2009-10-30 Sarbani Basu , H. M. Antia , S. C. Tripathy