文章基本信息

标题：Capabilities of bisector analysis of the Si  I 10 827 Å line for estimating line-of-sight velocities in the quiet Sun
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作者：S. J. González Manrique ; C. Quintero Noda ; C. Kuckein 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2020
卷号：634
页码：1-7
DOI：10.1051/0004-6361/201937274
语种：English
出版社：EDP Sciences
摘要：We examine the capabilities of a fast and simple method to infer line-of-sight (LOS) velocities from observations of the photospheric Si I10 827 Å line. This spectral line is routinely observed together with the chromospheric He I10 830 Å triplet as it helps to constrain the atmospheric parameters. We study the accuracy of bisector analysis and a line core fit of Si I10 827 Å. We employ synthetic profiles starting from the Bifrost enhanced network simulation. The profiles are computed solving the radiative transfer equation, including non-local thermodynamic equilibrium effects on the determination of the atomic level populations of Si I. We found a good correlation between the inferred velocities from bisectors taken at different line profile intensities and the original simulation velocity at given optical depths. This good correlation means that we can associate bisectors taken at different line-profile percentages with atmospheric layers that linearly increase as we scan lower spectral line intensities. We also determined that a fit to the line-core intensity is robust and reliable, providing information about atmospheric layers that are above those accessible through bisectors. Therefore, by combining both methods on the Si I10 827 Å line, we can seamlessly trace the quiet-Sun LOS velocity stratification from the deep photosphere to higher layers until around logτ = −3.5 in a fast and straightforward way. This method is ideal for generating quick-look reference images for future missions like theDaniel K. InoueSolar Telescope and the European Solar Telescope, for example.
关键词：enSun: atmosphereSun: photosphereradiative transfertechniques: spectroscopicmethods: data analysis