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We study the broadband polarization of hydrogen lines produced by scattering of radiation, in the presence of isotropic electric fields. In this paper, we focus on two distinct problems: a) the possibility of detecting the presence of…

Astrophysics · Physics 2024-09-04 R. Casini , R. Manso Sainz

Here we report on the first detection of circular polarization in molecular lines formed in cool magnetic regions (starspots) and in chromospheric emission lines formed in hot plages on the surfaces of active stars. Our survey of G-K-M…

Astrophysics · Physics 2007-05-23 S. V. Berdyugina , D. M. Fluri , N. Afram , F. Suwald , P. Petit , J. Arnaud , D. M. Harrington , J. R. Kuhn

The physical interpretation of the spectral line polarization produced by the joint action of the Hanle and Zeeman effects offers a unique opportunity to obtain empirical information about hidden aspects of solar and stellar magnetism. To…

Astrophysics · Physics 2009-06-23 Luca Belluzzi , Javier Trujillo Bueno , Egidio Landi Degl'Innocenti

Magnetic fields play essential roles in protoplanetary disks. Magnetic fields in the disk atmosphere are of particular interest, as they are connected to the wind-launching mechanism. In this work, we study the polarization of the light…

Earth and Planetary Astrophysics · Physics 2022-08-24 Haifeng Yang , Zhi-Yun Li

We explain the linear polarization of the Ca II infrared triplet observed close to the edge of the solar disk. In particular, we demonstrate that the physical origin of the enigmatic polarizations of the 866.2 nm and 854.2 nm lines lies in…

Astrophysics · Physics 2009-11-10 R. Manso Sainz , J. Trujillo Bueno

{Magnetic fields exist on all scales in our Galaxy. There is a controversy about whether the magnetic fields in molecular clouds are preserved from the permeated magnetic fields in the interstellar medium (ISM) during cloud formation. We…

Astrophysics · Physics 2008-08-14 J. L. Han , J. S. Zhang

Observational studies of magnetic fields are crucial. We introduce a process "ground state alignment" as a new way to determine the magnetic field direction in diffuse medium. The alignment is due to anisotropic radiation impinging on the…

Astrophysics of Galaxies · Physics 2013-02-15 Huirong Yan , A. Lazarian

We present a method for parametric modelling of the physical components of the Galaxy's magnetised interstellar medium, simulating the observables, and mapping out the likelihood space using a Markov Chain Monte-Carlo analysis. We then…

Astrophysics of Galaxies · Physics 2010-01-29 T. R. Jaffe , J. P. Leahy , A. J. Banday , S. M. Leach , S. R. Lowe , A. Wilkinson

The chromosphere of the quiet Sun is an important stellar atmospheric region whose thermal and magnetic structure we need to decipher for unlocking new discoveries in solar and stellar physics. To this end, we must identify and exploit…

Solar and Stellar Astrophysics · Physics 2015-05-19 R. Manso Sainz , J. Trujillo Bueno

We present the first self-consistent theoretical models of magnetar spectra that take into account the combined effects of the stellar atmosphere and its magnetosphere. We find that the proton cyclotron lines that are already weakened by…

Astrophysics · Physics 2007-05-23 Tolga Guver , Feryal Ozel , Maxim Lyutikov

This paper presents a detailed study of the scattering polarization profiles formed under partial frequency redistribution (PRD) in two thermal models of the solar atmosphere. Particular attention is given to understanding the influence of…

Solar and Stellar Astrophysics · Physics 2010-10-12 M. Sampoorna , J. Trujillo Bueno , E. Landi Degl'Innocenti

This paper shows the first synthetic tomography of the quiet solar chromosphere formed by spatial maps of scattering polarization. It has been calculated for the CaII 8498, 8542 and 3934 A lines by solving the NLTE (non-local…

Solar and Stellar Astrophysics · Physics 2015-06-23 E. S. Carlin , A Asensio Ramos

Within four nearby (d < 160 pc) molecular clouds, we statistically evaluate the structure of the interstellar magnetic field, projected on the plane of the sky and integrated along the line of sight, as inferred from the polarized thermal…

We performed a highly sensitive search for magnetic fields on a large set of HgMn stars. With the aid of a new polarimeter attached to the HARPS spectrometer at the ESO 3.6m-telescope, we obtained high-quality circular polarization spectra…

This paper provides testable predictions about starlight polarizations to constrain the geometry of the Galactic magnetic field, in particular the nature of the poloidal component. Galactic dynamo simulations and Galactic dust distributions…

Astrophysics of Galaxies · Physics 2012-02-07 Michael D. Pavel

The strengths of magnetic fields in interstellar gas clouds are obtained through observations of the circular polarization of spectral line radiation. Irregularities in this magnetic field may be present due to turbulence, waves or perhaps…

Astrophysics · Physics 2009-10-31 W. D. Watson , D. S. Wiebe , R. M. Crutcher

Solar chromospheric fibrils, as observed in the core of strong chromospheric spectral lines, extend from photospheric field concentrations suggesting that they trace magnetic field lines. These images have been historically used as proxies…

Solar and Stellar Astrophysics · Physics 2017-03-15 A. Asensio Ramos , J. de la Cruz Rodriguez , M. J. Martinez Gonzalez , H. Socas-Navarro

Observational studies of magnetic fields are vital as magnetic fields play a crucial role in various astrophysical processes, including star formation, accretion of matter, transport processes (e.g., transport of heat), and cosmic rays. We…

Astrophysics of Galaxies · Physics 2015-06-04 Huirong Yan , A. Lazarian

We investigate the possibility of measuring magnetic field strength in G-band bright points through the analysis of Zeeman polarization in molecular CH lines. To this end we solve the equations of polarized radiative transfer in the G band…

Astrophysics · Physics 2009-11-10 H. Uitenbroek , E. Miller-Ricci , A. Asensio Ramos , J. Trujillo Bueno

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…

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