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Full disk vector magnetic fields are used widely for developing better understanding of large-scale structure, morphology, and patterns of the solar magnetic field. The data are also important for modeling various solar phenomena. However,…

Solar and Stellar Astrophysics · Physics 2021-01-19 Alexei A. Pevtsov , Yang Liu , Ilpo Virtanen , Luca Bertello , Kalevi Mursula , K. D. Leka , Anna L. H. Hughes

We investigate theoretically the circular polarization signals induced by the Zeeman effect in the Fe II lines of the 279.3-280.7 nm spectral range of the CLASP2 space experiment and their suitability to infer solar magnetic fields. To this…

Solar and Stellar Astrophysics · Physics 2023-07-06 David Afonso Delgado , Tanausú del Pino Alemán , Javier Trujillo Bueno

Inferring magnetic and thermodynamic information from spectropolarimetric observations relies on the assumption of a parameterized model atmosphere whose parameters are tuned by comparison with observations. Often, the choice of the…

Solar and Stellar Astrophysics · Physics 2015-06-03 A. Asensio Ramos , R. Manso Sainz , M. J. Martinez Gonzalez , B. Viticchie , D. Orozco Suarez , H. Socas-Navarro

We deal with the analysis of on-off measurements designed for the confirmation of a weak source of events whose presence is hypothesized, based on former observations. The problem of a small number of source events that are masked by an…

Instrumentation and Methods for Astrophysics · Physics 2017-08-23 Dalibor Nosek , Jana Nosková

With the recent advent of circular polarization capabilities at the Atacama Large Millimeter/submillimeter Array (ALMA), Zeeman effect measurements of spectral lines are now possible as a means to directly probe line-of-sight magnetic…

Solar and Stellar Astrophysics · Physics 2020-11-04 Renato Mazzei , L. Ilsedore Cleeves , Zhi-Yun Li

Bayesian model selection is a tool to decide whether the introduction of a new parameter is warranted by data. I argue that the usual sampling statistic significance tests for a null hypothesis can be misleading, since they do not take into…

Astrophysics · Physics 2008-11-26 Roberto Trotta

Zeeman-Doppler imaging (ZDI) is used to study the surface magnetic field topology of stars, based on high-resolution spectropolarimetric time series observations. Multiple ZDI inversions have been conducted for the early B-type star tau…

Solar and Stellar Astrophysics · Physics 2025-07-02 Jennifer Rosina Andersson , Oleg Kochukhov , Zheng Zhao , Jens Sjölund

High resolution observations have permitted to resolve the solar prominences/filaments as sets of threads/fibrils. However, the values of the physical parameters of these threads and their structuring remain poorly constrained. We use…

Solar and Stellar Astrophysics · Physics 2019-02-06 M. Montes-Solís , I. Arregui

We present a general radiative transfer model which allows the Zeeman diagnostics of complex and unresolved solar magnetic fields. Present modeling techniques still rely to a large extent on a-priori assumptions about the geometry of the…

Astrophysics · Physics 2009-11-13 T. A. Carroll , M. Kopf

We study the quiet Sun magnetic fields using spectropolarimetric observations of the infrared and visible Fe I lines at 6301.5, 6302.5, 15648 and 15653 A. Magnetic field strengths and filling factors are inferred by the simultaneous fit of…

Astrophysics · Physics 2008-11-26 Itahiza Dominguez Cerdena , Jorge Sanchez Almeida , Franz Kneer

The relationship between the magnetic field and the circular polarization of astrophysical maser radiation due to the Zeeman effect under idealized conditions is investigated when the Zeeman splitting is much smaller than the spectral…

Astrophysics · Physics 2009-11-07 W. D. Watson , H. W. Wyld

Recent comparisons of magnetic field directions derived from maser Zeeman splitting with those derived from continuum source rotation measures have prompted new analysis of the propagation of the Zeeman split components, and the inferred…

Astrophysics of Galaxies · Physics 2015-06-19 J. A. Green , M. D. Gray , T. Robishaw , J. L. Caswell , N. M. McClure-Griffiths

Some recent investigations of spectropolarimetric observations of the Zeeman effect in the Fe I lines at 630 nm carried out with the Hinode solar space telescope have concluded that the strength of the magnetic field vector in the…

Solar and Stellar Astrophysics · Physics 2009-08-05 A. Asensio Ramos

The measurement of solar magnetic fields using the Zeeman effect diagnostics has a fundamental 180 degree ambiguity in the determination of the azimuth angle of the transverse field component. There are several methods that are used in the…

Solar and Stellar Astrophysics · Physics 2015-06-11 Sanjay Gosain , Alexei A. Pevtsov

The influence of a magnetic field on the broadening of spectral lines and transition arrays in complex spectra is investigated. The anomalous absorption or emission Zeeman pattern is a superposition of many profiles with different relative…

Atomic Physics · Physics 2019-04-30 Jean-Christophe Pain , Franck Gilleron

We present a field-based signal extraction of weak lensing from noisy observations on the curved and masked sky. We test the analysis on a simulated Euclid-like survey, using a Euclid-like mask and noise level. To make optimal use of the…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-09 A. Loureiro , L. Whiteway , E. Sellentin , J. S. Lafaurie , A. H. Jaffe , A. F. Heavens

A classic application of coronal seismology uses transverse oscillations of waveguides to obtain estimates of the magnetic field strength. The procedure requires information on the density of the structures. Often, it ignores the damping of…

Solar and Stellar Astrophysics · Physics 2019-05-08 I. Arregui , M. Montes-Solis , A. Asensio Ramos

Zeeman observations provide the only direct probe of line-of-sight (LOS) magnetic fields in the interstellar medium. To evaluate their accuracy and limitations, we generate synthetic HI Zeeman spectra from magnetohydrodynamic simulations…

Astrophysics of Galaxies · Physics 2026-02-24 Duo Xu , Peter Martin , Stella Offner , Robert Gutermuth , Michael Grudic , Joshua Speagle

Electric currents play an important role in the energy balance of the plasma in the solar atmosphere. They are also indicative of non-potential magnetic fields and magnetic reconnection. Unfortunately, the direct measuring of electric…

Solar and Stellar Astrophysics · Physics 2023-01-25 J. M. Borrero , A. Pastor Yabar

The topic of magnetic field diagnostics with the Zeeman effect is currently vividly discussed. There are some testable inversion codes available to the spectropolarimetry community and their application allowed for a better understanding of…

Solar and Stellar Astrophysics · Physics 2016-11-29 M. Derouich