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Related papers: Comparative clustering analysis of Ca II 854.2 nm …

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CHROMIS, a new imaging spectrometer at the Swedish 1-m Solar Telescope (SST), can observe the chromosphere in the H and K lines of Ca II at high spatial and spectral resolution. Accurate modeling as well as an understanding of the formation…

The new CRISP filter at the Swedish 1-m Solar Telescope provides opportunities for observing the solar atmosphere with unprecedented spatial resolution and cadence. In order to benefit from the high quality of observational data from this…

Solar and Stellar Astrophysics · Physics 2012-04-23 Jaime de la Cruz Rodríguez

Context. The wings of the Ca II H and K lines provide excellent photospheric temperature diagnostics. At the Swedish 1-meter Solar Telescope the blue wing of Ca II H is scanned with a narrowband interference filter mounted on a rotation…

Solar and Stellar Astrophysics · Physics 2012-12-18 V. M. J. Henriques

The Ca ii 854.2 nm line is widely used to study the chromosphere of the Sun. In the quiet Sun, the spatially averaged line profile shows a red asymmetry and a redshift of the line center. It is known that the effect of isotopic splitting…

Solar and Stellar Astrophysics · Physics 2026-03-25 P. A. Ondratschek , D. Przybylski , H. N. Smitha , R. H. Cameron , S. K. Solanki

The shapes of Stokes profiles contain much information about the atmospheric conditions that produced them. However, a variety of different atmospheric structures can produce very similar profiles. Thus, it is important for proper…

Solar and Stellar Astrophysics · Physics 2023-07-12 Thore Espedal Moe , Tiago M. D. Pereira , Flavio Calvo , Jorrit Leenaarts

The heating of the Sun's chromosphere remains poorly understood. While progress has been made on understanding what drives the quiet Sun internetwork chromosphere, chromospheric heating in strong magnetic field regions continues to present…

Solar and Stellar Astrophysics · Physics 2013-02-07 J. de la Cruz Rodríguez , B. De Pontieu , M. Carlsson , L. H. M. Rouppe van der Voort

Interpreting the Stokes profiles observed in quiet regions of the solar chromosphere is a challenging task. The Stokes Q and U profiles are dominated by the scattering polarisation and the Hanle effect, and these processes can only be…

Solar and Stellar Astrophysics · Physics 2018-11-07 Jan Jurcak , Jiri Stepan , Javier Trujillo Bueno , Michele Bianda

Imaging spectrographs are popular instruments used to obtain solar data. They record quasi-monochromatic images at selected wavelength positions. By scanning the spectral range of the line, it is possible to obtain bidimensional maps of the…

Solar and Stellar Astrophysics · Physics 2019-12-04 T. Felipe , S. Esteban Pozuelo

In the present work, we introduce and explain a method of solution of the radiative transfer equation based on a thin cloud model. The efficiency of this method to retrieve dynamical chromospheric parameters from Stokes I profiles of Ca II…

Solar and Stellar Astrophysics · Physics 2016-12-21 H. Hamedivafa , M. Sobotka , L. Bellot Rubio , S. Esteban Pozuelo

We use 3D radiation magnetohydrodynamic models to investigate how the thermodynamic quantities in the simulation are encoded in observable quantities, thus exploring the diagnostic potential of the 133.5 nm lines. We find that the line core…

Solar and Stellar Astrophysics · Physics 2015-09-30 Bhavna Rathore , Mats Carlsson , Jorrit Leenaarts , Bart De Pontieu

Studying the emergence of magnetic fields is essential for understanding the physical mechanisms behind various phenomena in the solar atmosphere. Most importantly, the emerging fields offer valuable insights into how energy and mass are…

Solar and Stellar Astrophysics · Physics 2025-08-28 Milan Gošić , Viggo H. Hansteen , Alberto Sainz Dalda , Bart De Pontieu , Luc H. M. Rouppe van der Voort

The Ca II infrared triplet around 8540 A is a good candidate for observing chromospheric magnetism. We show results from combining a radiation hydrodynamic simulation with a Stokes synthesis code. The simulation shows interesting…

Astrophysics · Physics 2009-11-13 A. Pietarila , H. Socas-Navarro , T. Bogdan , M. Carlsson , R. F. Stein

We study chromospheric emission to understand the temperature stratification in the solar chromosphere. We observed the intensity profile of the CaIIH line in a quiet Sun region close to the disk center at the German Vacuum Tower Telescope.…

Astrophysics · Physics 2009-11-13 R. Rezaei , J. H. M. J. Bruls , W. Schmidt , C. Beck , W. Kalkofen , R. Schlichenmaier

The Mg I b$_2$ line at 5173 \r{A} is primarily magnetically sensitive to heights between the mid photosphere and the low chromosphere, a region that has not been sufficiently explored in the solar atmosphere but is crucial for understanding…

Solar and Stellar Astrophysics · Physics 2025-03-18 A. L. Siu-Tapia , L. R. Bellot Rubio , D. Orozco Suárez , R. Gafeira

Flare loops form an integral part of eruptive events, being detected in the range of temperatures from X-rays down to cool chromospheric-like plasmas. While the hot loops are routinely observed by the Solar Dynamics Observatory's…

Solar and Stellar Astrophysics · Physics 2020-01-08 Július Koza , David Kuridze , Petr Heinzel , Sonja Jejčič , Huw Morgan , Maciej Zapiór

The sunspot umbra harbors the coolest plasma on the solar surface due to the presence of strong magnetic fields. The routinely used atomic lines to observe the photosphere have weak signals in the umbra and are often swamped by molecular…

Solar and Stellar Astrophysics · Physics 2021-09-15 H. N. Smitha , J. S. Castellanos Durán , S. K. Solanki , S. K. Tiwari

(Abridged) Aims: In this paper, we seek to establish the suitability of imaging spectroscopy performed in the Ca II 854.2 nm line as a means to investigate the solar chromosphere at high resolution. Methods: We utilize monochromatic images…

We analysed state-of-the-art observations of the solar atmosphere to investigate the dependence of the \ca brightness of several solar features on spectral bandwidth and spatial resolution of the data. Specifically, we study data obtained…

Solar and Stellar Astrophysics · Physics 2023-04-20 M. Murabito , I. Ermolli , T. Chatzistergos , S. Jafarzadeh , F. Giorgi , L. Rouppe van der Voort

Aims. We measure, as far out as possible, radial temperature profiles for a sample of ~50 hot, intermediate redshift galaxy clusters, selected from the XMM-Newton archive, keeping systematic errors under control. Methods. Our work is…

Astrophysics · Physics 2009-11-13 A. Leccardi , S. Molendi

We study non-LTE inversions of the Ca II infrared triplet lines as a tool for inferring physical properties of the quiet Sun. The inversion code is successful in recovering the temperature, velocity and longitudinal magnetic flux density in…

Astrophysics · Physics 2011-02-11 A. Pietarila , H. Socas-Navarro , T. Bogdan
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