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Related papers: Diagnostics for the solar chromosphere using neutr…

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Context. The surface structures and dynamics of cool stars are characterized by the presence of convective motions and turbulent flows which shape the emergent spectrum. Aims. We used realistic three-dimensional radiative hydrodynamical…

Solar and Stellar Astrophysics · Physics 2018-03-14 A. Chiavassa , L. Casagrande , R. Collet , Z. Magic , L. Bigot , F. Thevenin , M. Asplund

The chromosphere in internetwork regions of the quiet Sun was regarded as a static and homogeneous layer for a long time. Thanks to advances in observations and numerical modelling, the wave nature of these atmospheric regions received…

Astrophysics · Physics 2015-06-24 Sven Wedemeyer-Böhm

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

During solar flares, spectral lines formed in the photosphere have been shown to exhibit changes to their profiles despite the challenges of energy transfer to these depths. Recent work has shown that deep-forming spectral lines are subject…

Solar and Stellar Astrophysics · Physics 2024-01-05 Aaron J. Monson , Mihalis Mathioudakis , Adam F. Kowalski

The specification of the upper atmosphere strongly relies on solar proxies that can properly reproduce the solar energetic input in the UV. Whilst the microwave flux at 10.7 cm (also called F10.7 index) has been routinely used as a solar…

Solar and Stellar Astrophysics · Physics 2014-02-18 Thierry Dudok de Wit , Sean Bruinsma , Kiyoto Shibasaki

We analyze the ultraviolet (UV) emission line and continuum properties of five low-redshift active galactic nuclei (four luminous quasars: PKS~0405$-$123, H1821+643, PG~0953+414, and 3C273, and one bright Seyfert 1 galaxy: Mrk~205). The HST…

The structure and energy balance of the solar chromosphere remain poorly known. We have used the imaging spectrometer IBIS at the Dunn Solar Telescope to obtain fast-cadence, multi-wavelength profile sampling of Halpha and Ca II 854.2 nm…

Solar and Stellar Astrophysics · Physics 2015-05-13 G. Cauzzi , K. P. Reardon , R. J. Rutten , A. Tritschler , H. Uitenbroek

Balmer lines are an important diagnostic of stellar atmospheric structure, since they are formed at a wide range of depths within the atmosphere. The different Balmer lines are formed at slightly different depths making them useful…

Astrophysics · Physics 2007-05-23 B. Smalley , F. Kupka

The reconstruction of the differential emission measure (DEM) from observations of spectral line intensities provides information on the temperature distribution of the emission measure in the region observed. The inversion process is known…

Solar and Stellar Astrophysics · Physics 2022-05-18 Kenneth P. Dere

We benchmark new atomic data against a selection of irradiances obtained from medium-resolution quiet Sun spectra in the EUV, from 60 to 1040 \AA. We use as a baseline the irradiances measured during solar minimum on 2008 April 14 by the…

Solar and Stellar Astrophysics · Physics 2019-04-03 G. Del Zanna

Present-day semi-empirical models of solar irradiance (SI) variations employ spectra computed on one-dimensional atmosphere models (1D models) representative of various solar surface features to reconstruct SI changes measured on timescales…

Solar and Stellar Astrophysics · Physics 2017-06-14 A. Cristaldi , I. Ermolli

Optical emission lines are used to categorize galaxies into three groups according to their dominant central radiation source: active galactic nuclei, star formation, or low-ionization (nuclear) emission regions [LI(N)ERs] that may trace…

Astrophysics of Galaxies · Physics 2020-07-07 Dhanesh Krishnarao , Robert A. Benjamin , L. Matthew Haffner

Rydberg atoms as versatile tools for quantum applications are extremely sensitive to electric fields. When utilizing these atoms, it becomes imperative to comprehensively characterize and mitigate any residual electric fields present in the…

In this work, we present a photospheric solar silicon abundance derived using CO5BOLD model atmospheres and the LINFOR3D spectral synthesis code. Previous works have differed in their choice of a spectral line sample and model atmosphere as…

Solar and Stellar Astrophysics · Physics 2022-12-16 S. A. Deshmukh , H. -G. Ludwig , A. Kučinskas , M. Steffen , P. S. Barklem , E. Caffau , V. Dobrovolskas , P. Bonifacio

This paper reviews some recent advances in the development and application of polarized radiation diagnostics to infer the mean magnetization of the quiet solar atmosphere, from the near equilibrium photosphere to the highly non-equilibrium…

Solar and Stellar Astrophysics · Physics 2010-02-15 J. Trujillo Bueno

Alfvenic waves are ubiquitous in the solar atmosphere and their dissipation may play an important role in atmospheric heating. In the partially ionized solar chromosphere, collisions between ions and neutrals are an efficient dissipative…

Solar and Stellar Astrophysics · Physics 2014-12-24 R. Soler , J. L. Ballester , T. V. Zaqarashvili

A major challenge in solar physics is to obtain empirical information on the magnetic field of the million-degree plasma of the solar corona. To this end, we need observables of the solar radiation sensitive to the coronal magnetic field.…

We investigate the thermal response of the atmosphere of a solar-type star to an electron beam injected from a hot Jupiter by performing a 1-dimensional magnetohydrodynamic numerical experiment with non-linear wave dissipation, radiative…

Solar and Stellar Astrophysics · Physics 2014-11-20 Pin-Gao Gu , Takeru K. Suzuki

We investigate the morphology and temporal variability of a quiet Sun network region in different solar layers. The emission in several EUV spectral lines through both raster and slot time series, recorded by EIS/Hinode is studied along…

Solar and Stellar Astrophysics · Physics 2018-03-26 Ioannis Kontogiannis , Costis Gontikakis , Georgia Tsiropoula , Kostas Tziotziou

Hidden photons, gauge bosons of a U(1) symmetry of a hidden sector, can constitute the dark matter of the universe and a smoking gun for large volume compactifications of string theory. In the sub-eV mass range, a possible discovery…

High Energy Physics - Phenomenology · Physics 2015-08-06 Javier Redondo