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We present a dataset of high resolution spectra of the Sun of many strongly polarized lines belonging to the second solar spectrum, i.e. the spectrum near the limb in linear polarization (scattering polarization). These solar spectra were…

Instrumentation and Methods for Astrophysics · Physics 2025-05-08 Jean-Marie Malherbe

We present the Cosmic Lyman-$\alpha$ Transfer code (COLT), a massively parallel Monte-Carlo radiative transfer code, to simulate Lyman-$\alpha$ (Ly$\alpha$) resonant scattering through neutral hydrogen as a probe of the first galaxies. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Aaron Smith , Chalence Safranek-Shrader , Volker Bromm , Miloš Milosavljević

The solar surface magnetic field is connected with and even controls most of the solar activity phenomena. Zeeman effect diagnostics allow for measuring only a small fraction of the fractal-like structured magnetic field. The remaining…

Solar and Stellar Astrophysics · Physics 2015-05-27 A. I. Shapiro , D. M. Fluri , S. V. Berdyugina , M. Bianda , R. Ramelli

Ellerman bombs are bright emission features observed in the wings of H$\alpha$, usually in the vicinity of magnetic concentrations. Here we show that they can also be detected in the Ca II infrared triplet lines, which are easier to…

The polarization of radiation by scattering on an atom embedded in combined external quadrupole electric and uniform magnetic fields is studied theoretically. Limiting cases of scattering under Zeeman effect and Hanle effect in weak…

Astrophysics · Physics 2015-06-24 Yee Yee Oo , M. Sampoorna , K. N. Nagendra , Sharath Ananthamurthy , G. Ramachandran

The hydrogen Lyman lines provide important diagnostic information about the dynamics of the chromosphere, but there have been few systematic studies of their variability during flares. We investigate Doppler shifts in these lines in several…

Solar and Stellar Astrophysics · Physics 2016-11-30 Stephen A Brown , Lyndsay Fletcher , Nicolas Labrosse

Background: Measurements of the polarization observables {\Sigma}, P, T, Ox, Oz for the reaction {\gamma}p {\rightarrow) KS0 {\Sigma}+ using a linearly polarized photon beam of energy 1.1 to 2.1 GeV are reported. Purpose: The measured data…

Nuclear Experiment · Physics 2024-05-01 CLAS Collaboration , L. Clark , B. McKinnon , D. G. Ireland , D. I. Glazier , K. Livingston , D. Rönchen

We investigate the diagnostic potential of the spectral lines at 850 nm for understanding the magnetism of the lower atmosphere. For that purpose, we use a newly developed 3D simulation of a chromospheric jet to check the sensitivity of the…

Hanle effect is ubiquitous in the study of spin-related phenomena and has been used to determine spin lifetime, precession and transport in semiconductors. Here, we report an experimental observation of anomalous Hanle effect in individual…

Mesoscale and Nanoscale Physics · Physics 2009-10-12 O. Krebs , P. Maletinsky , T. Amand , B. Urbaszek , A. Lemaître , P. Voisin , X. Marie , A. Imamoglu

The Lyman Continuum (LyC; $<911.12$\AA) forms at the top of the chromosphere in the quiet-Sun, making LyC a powerful tool for probing the chromospheric plasma during solar flares. To understand the effects of non-thermal energy deposition…

Solar and Stellar Astrophysics · Physics 2023-03-01 Shaun A. McLaughlin , Ryan O. Milligan , Graham S. Kerr , Aaron J. Monson , Paulo J. A. Simões , Mihalis Mathioudakis

We report measurements of electron-impact excitation cross sections for the strong K-shell n=2-1 transitions in S XV using the LLNL EBIT-I electron beam ion trap, two crystal spectrometers, and the EBIT Calorimeter Spectrometer. The cross…

Laser-induced breakdown spectroscopy (LIBS) is a well-established technique widely used in fundamental research and diverse practical fields. Polarization-resolved LIBS, a variant of this technique, aims to improve the sensitivity, which is…

Plasma Physics · Physics 2024-10-11 B. R. Geethika , Jinto Thomas , Renjith Kumar R , Janvi Dave , Hem Chandra Joshi

Low-lying loops have been discovered at the solar limb in transition region temperatures by the Interface Region Imaging Spectrograph (IRIS). They do not appear to reach coronal temperatures, and it has been suggested that they are the…

Solar and Stellar Astrophysics · Physics 2018-04-11 Tiago M. D. Pereira , Luc Rouppe van der Voort , Viggo H. Hansteen , Bart De Pontieu

Scattering polarization in the Sr I 4607.3 \AA \ line observed with high resolution is an important diagnostic of the Sun's atmosphere and magnetism at small spatial scales. At present, spatially resolved observations of this diagnostic are…

Solar and Stellar Astrophysics · Physics 2018-11-28 F. Zeuner , A. Feller , F. A. Iglesias , S. K. Solanki

We present the results from the first large (>100 source) 3.5 mm polarimetric survey of radio loud active galactic nuclei (AGN). The I, Q, U, and V Stokes parameter observations were performed with the XPOL polarimeter at the IRAM 30m…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 I. Agudo , C. Thum , H. Wiesemeyer , T. P. Krichbaum

The Chromospheric LAyer SpectroPolarimeter missions, CLASP2 and CLASP2.1, demonstrated that the near-UV spectral region between 279.30 and 280.68 nm is suitable for studying the magnetism of the solar chromosphere. In particular, the…

Calibration of radio interferometric observations becomes increasingly difficult towards lower frequencies. Below ~300 MHz, spatially variant refractions and propagation delays of radio waves traveling through the ionosphere cause phase…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 H. T. Intema , S. van der Tol , W. D. Cotton , A. S. Cohen , I. M. van Bemmel , H. J. A. Rottgering

We report on the detection of linear polarization of the forbidden [O i] 630.03 nm spectral line. The observations were carried out in the broader context of the determination of the solar oxygen abundance, an important problem in…

Solar and Stellar Astrophysics · Physics 2021-02-03 A. G. de Wijn , H. Socas-Navarro , N. Vitas

Due to the quick evolution of the solar chromosphere, its magnetic field cannot be inferred reliably without accounting for the temporal variations of its polarized light. This has been broadly overlooked in the modelling and interpretation…

Solar and Stellar Astrophysics · Physics 2017-07-19 E. S. Carlin , M. Bianda

Context. We present a theoretical review of the effect of impact polarization of a hydrogen H$\alpha$ line due to an expected proton beam bombardment in solar flares. Aims. Several observations indicate the presence of the linear…

Astrophysics · Physics 2008-11-26 Jiri Stepan , Petr Heinzel , Sylvie Sahal-Brechot