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Related papers: Optimal spectral lines for measuring chromospheric…

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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

Magnetic fields are the primary driver of the plasma thermodynamics in the upper solar atmosphere, especially in the corona. However, magnetic field measurements in the solar corona are sporadic, thereby limiting us from the complete…

Solar and Stellar Astrophysics · Physics 2024-06-12 Raveena Khan , Sarah E. Gibson , Roberto Casini , K. Nagaraju

We present joint observations of the Sun by the Atacama Large Millimeter/submillimeter Array (ALMA) and the Interface Region Imaging Spectrograph (IRIS). The observations were made of a solar active region on 2015 December 18 as part of the…

Solar and Stellar Astrophysics · Physics 2017-08-30 T. S. Bastian , G. Chintzoglou , B. De Pontieu , M. Shimojo , D. Schmit , J. Leenaarts , M. Loukitcheva

We tested whether simultaneous spectropolarimetric imaging in two magnetically sensitive optical spectral lines, which probe two different layers of the solar atmosphere (the photosphere and the temperature minimum), can help constrain the…

The critical need to study the magnetic field in the solar corona is highlighted by recent observational facilities, such as DKIST and Aditya-L1. A powerful tool for probing the magnetism of the solar corona is forward modeling of the…

The study of magnetars is of particular relevance since these objects are the only laboratories where the physics in ultra-strong magnetic fields can be directly tested. Until now, spectroscopic and timing measurements at X-ray energies in…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Roberto Taverna , Fabio Muleri , Roberto Turolla , Paolo Soffitta , Sergio Fabiani , Luciano Nobili

We demonstrate that the combination of Zeeman, polarimetry and ion-to-neutral molecular line width ratio measurements permits the determination of the magnitude and orientation of the magnetic field in the weakly ionized parts of molecular…

Observations of the Sun in the visible spectral range belong to standard measurements obtained by instruments both on the ground and in the space. Nowadays, both nearly continuous full-disc observations with medium resolution and dedicated…

Solar and Stellar Astrophysics · Physics 2020-06-30 Michal Švanda , Jan Jurčák , David Korda , Jana Kašparová

In solar physics, it is a big challenge to measure the magnetic fields directly from observations in the upper solar atmosphere, including the chromosphere and corona. Radio observations are regarded as the most feasible approach to…

Solar and Stellar Astrophysics · Physics 2022-06-22 Baolin Tan

We highlight the main results of a radiative transfer investigation on the magnetic sensitivity of the solar Mg ii k resonance line at 2795.5 angstrom, accounting for the joint action of the Hanle and Zeeman effects as well as partial…

Solar and Stellar Astrophysics · Physics 2016-11-09 Ernest Alsina Ballester , Luca Belluzzi , Javier Trujillo Bueno

Aims. We analyze observational data from 4 instruments to study the correlations between chromospheric emission, spanning the heights from the temperature minimum region to the middle chromosphere, and photospheric magnetic field. Methods:…

Solar and Stellar Astrophysics · Physics 2014-11-20 Maria A. Loukitcheva , Sami K. Solanki , Stephen M. White

Magnetic fields in the solar corona are responsible for a wide range of phenomena. However, any direct measurements of the coronal magnetic fields are very difficult due to lack of suitable spectral lines, weak magnetic fields, and high…

Solar and Stellar Astrophysics · Physics 2013-10-28 P. Vemareddy , A. Ambastha , T. Wiegelmann

We present a novel technique that uses the autocorrelation of the spectrum of a star to measure the line broadening caused by the modulus of its average surface magnetic field. The advantage of the autocorrelation comes from the fact that…

Solar and Stellar Astrophysics · Physics 2015-10-21 Ermanno F. Borra , David Deschatelets

X-ray line fluorescence is ubiquitous around powerful accretion sources, namely active galactic nuclei and X-ray binaries. The brightest and best-studied line is the Fe K$\alpha$ line at $\lambda = 1.937$\AA (6.4\,keV). This paper presents…

High Energy Astrophysical Phenomena · Physics 2020-11-25 Roi Rahin , Ehud Behar

Magnetic field couples the solar interior to the solar atmosphere, known as the corona. The coronal magnetic field is one of the crucial parameters which determines the coronal structures and regulates the space weather phenomena like…

Solar and Stellar Astrophysics · Physics 2022-07-26 Devojyoti Kansabanik , Divya Oberoi , Surajit Mondal

With this work, we have conducted an extensive search for magnetic fields in the photosphere of $\alpha$~And. We have acquired new circular polarisation spectra with the MuSiCoS and ESPaDOnS sp ectropolarimeters. We have also obtained FORS1…

The magnetic field plays a major role in governing the dynamics of the sun. Many interesting features like sunspots, flares, prominences, and Coronal Mass Ejections (CMEs) occur on its surface due to the dynamics associated with the…

Instrumentation and Methods for Astrophysics · Physics 2016-12-14 Souvik Bose

Observations of the upper chromosphere shows an enormous amount of intricate fine structure. Much of this comes in the form of linear features which are most often assumed to be well aligned with the direction of the magnetic field in the…

Solar and Stellar Astrophysics · Physics 2017-10-23 Juan Martínez-Sykora , Bart De Pontieu , Mats Carlsson , Viggo Hansteen

The magnetic field permeating the solar atmosphere is generally thought to provide the energy for much of the activity seen in the solar corona, such as flares, coronal mass ejections (CMEs), etc. To overcome the unavailability of coronal…

Solar and Stellar Astrophysics · Physics 2015-06-17 Tilaye Tadesse , T. Wiegelmann , S. Gosain , P. MacNeice , Alexei A. Pevtsov

Model atmospheres of A and B stars are computed taking into account magnetic line blanketing. These calculations are based on the new stellar model atmosphere code LLModels which implements direct treatment of the opacities due to the…

Astrophysics · Physics 2009-11-10 O. Kochukhov , S. Khan , D. Shulyak
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