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Related papers: Mg II h&k spectral line properties computed using …

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The Mg ii h&k lines are key diagnostics of the solar chromosphere. They are sensitive to the temperature, density, and non-thermal velocities in the chromosphere. The average Mg ii h&k line profiles arising from previous 3D chromospheric…

Solar and Stellar Astrophysics · Physics 2024-11-27 P. Ondratschek , D. Przybylski , H. N. Smitha , R. Cameron , S. K. Solanki , J. Leenaarts

NASA's Interface Region Imaging Spectrograph (IRIS) space mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h&k lines as well as a slit-jaw imager centered at Mg II k.…

Solar and Stellar Astrophysics · Physics 2015-06-16 J. Leenaarts , T. M. D. Pereira , M. Carlsson , H. Uitenbroek , B. de Pontieu

The Mg II h&k lines are amongst the best diagnostic tools of the upper solar chromosphere. This region of the atmosphere is of particular interest as it is the lowest region of the Sun's atmosphere where the magnetic field is dominant in…

Solar and Stellar Astrophysics · Physics 2023-03-01 Viggo Hansteen , Juan Martinez Sykora , Mats Carlsson , Bart De Pontieu , Milan Gosic , Souvik Bose

The Mg II h&k lines are powerful diagnostics for studying the solar chromosphere. They have become particularly popular with the launch of the IRIS satellite, and a number of studies that include these lines have lead to great progress in…

Solar and Stellar Astrophysics · Physics 2016-10-21 Jaime de la Cruz Rodríguez , Jorrit Leenaarts , Andrés Asensio Ramos

Resonance spectral lines such as H I Ly {\alpha}, Mg II h&k, and Ca II H&K that form in the solar chromosphere are influenced by the effects of 3D radiative transfer as well as partial redistribution (PRD). So far no one has modeled these…

Solar and Stellar Astrophysics · Physics 2016-12-28 Andrii V. Sukhorukov , Jorrit Leenaarts

NASA's Interface Region Imaging Spectrograph (IRIS) small explorer mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h&k lines as well as a slit-jaw imager centered at Mg…

Solar and Stellar Astrophysics · Physics 2015-06-16 J. Leenaarts , T. M. D. Pereira , M. Carlsson , H. Uitenbroek , B. de Pontieu

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…

A triplet of subordinate lines of Mg II exists in the region around the h&k lines. In solar spectra these lines are seen mostly in absorption, but in some cases can become emission lines. The aim of this work is to study the formation of…

Solar and Stellar Astrophysics · Physics 2015-08-19 Tiago M. D. Pereira , Mats Carlsson , Bart De Pontieu , Viggo Hansteen

The Interface Region Imaging Spectrograph (IRIS) has routinely observed the flaring Mg II NUV spectrum, offering excellent diagnostic potential and a window into the location of energy deposition. A number of studies have forward modelled…

Solar and Stellar Astrophysics · Physics 2019-10-02 G. S. Kerr , Joel C. Allred , Mats Carlsson

Radiative transfer (RT) studies of the linearly polarized spectrum of the Sun (the second solar spectrum) have generally focused on the line formation, with an aim to understand the vertical structure of the solar atmosphere using…

Solar and Stellar Astrophysics · Physics 2013-08-16 L. S. Anusha , K. N. Nagendra

We present results of non-LTE modeling of H-alpha 6563 A and Mg II k&h 2796 A and 2803 A lines. This modeling is important for interpretation of coordinated observations from the recently launched NASA's IRIS mission and from the New Solar…

Solar and Stellar Astrophysics · Physics 2014-12-02 Viacheslav M. Sadykov , Alexander G. Kosovichev

Observations from the \textit{Interface Region Imaging Spectrograph} (\textsl{IRIS}) often reveal significantly broadened and non-reversed profiles of the Mg II h, k and triplet lines at flare ribbons. To understand the formation of these…

Solar and Stellar Astrophysics · Physics 2019-07-10 Yingjie Zhu , Adam F. Kowalski , Hui Tian , Han Uitenbroek , Mats Carlsson , Joel C. Allred

The flare activity of the Sun has been studied for decades, using both space- and ground-based telescopes. In particular, the Interface Region Imaging Spectrograph (IRIS) provides unique diagnostics to investigate the thermodynamics of…

Solar and Stellar Astrophysics · Physics 2022-11-11 Alberto Sainz Dalda , Bart De Pontieu

Solar flares show highly unusual spectra, in which the thermodynamic conditions of the solar atmosphere are encoded. Current models are unable to fully reproduce the spectroscopic flare observations, especially the single-peaked spectral…

Solar and Stellar Astrophysics · Physics 2017-06-28 Fatima Rubio da Costa , Lucia Kleint

The Mg II h&k lines are the prime chromospheric diagnostics of NASA's Interface Region Imaging Spectrograph (IRIS). In the previous papers of this series we used a realistic three-dimensional radiative magnetohydrodynamics model to…

Solar and Stellar Astrophysics · Physics 2013-11-21 Tiago M. D. Pereira , Jorrit Leenaarts , Bart De Pontieu , Mats Carlsson , Han Uitenbroek

The bulk of the radiative output of a solar flare is emitted from the chromosphere, which produces enhancements in the optical and UV continuum, and in many lines, both optically thick and thin. We have, until very recently, lacked…

Solar and Stellar Astrophysics · Physics 2015-10-07 Graham S. Kerr , Paulo J. A. Simões , Jiong Qiu , Lyndsay Fletcher

The complex spectropolarimetric patterns around strong chromospheric lines, the result of subtle spectroscopic and transport mechanisms, are sensitive, sometimes in unexpected ways, to the presence of magnetic fields in the chromosphere,…

Solar and Stellar Astrophysics · Physics 2017-10-12 R. Manso Sainz , T. del Pino Alemán , R. Casini

Non-local thermodynamic equilibrium (NLTE) effects in diagnostically important solar Fe I lines are important due to the strong sensitivity of Fe I to ionizing UV radiation, which may lead to a considerable under-population of the Fe I…

Solar and Stellar Astrophysics · Physics 2015-10-21 René Holzreuter , Sami K. Solanki

We investigated the formation of the Mg II h-k doublet in a weakly magnetized atmosphere (20-100 G) using a newly developed numerical code for polarized RT in a plane-parallel geometry, which implements a recent formulation of partially…

Solar and Stellar Astrophysics · Physics 2016-10-19 Tanausú del Pino Alemán , Roberto Casini , Rafael Manso Sainz

Detailed numerical models of chromosphere and corona are required to understand the heating of the solar atmosphere. An accurate treatment of the solar chromosphere is complicated by the effects arising from Non Local Thermodynamic…

Solar and Stellar Astrophysics · Physics 2022-08-17 D. Przybylski , R. Cameron , S. K. Solanki , M. Rempel , J. Leenaarts , L. S. Anusha , V. Witzke , A. I. Shapiro
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