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This work aims to identify the relevant physical processes in shaping the intensity and polarization patterns of the solar K I D lines through spectral syntheses, placing particular emphasis on the D2 line. The theoretical Stokes profiles…
The magnetic field is known to play a crucial role in star formation. Dust polarization is an effective tool for probing the morphology of the field, yet it does not directly trace its strength. Several methods have been developed,…
[abridged] Inversion techniques are the most powerful methods to obtain information about the thermodynamical and magnetic properties of solar and stellar atmospheres. In the last years, we have witnessed the development of highly…
The study of polarized radiation transfer in the highly-magnetized surface locales of neutron stars is of great interest to the understanding of accreting X-ray pulsars, rotation-powered pulsars and magnetars. This paper explores scattering…
In this paper we study the feasibility of inferring the magnetic field from polarized multi-line spectra using two methods: The pseudo line approach and The PCA-ZDI approach. We use multi-line techniques, meaning that all the lines of a…
Regression methods based in Machine Learning Algorithms (MLA) have become an important tool for data analysis in many different disciplines. In this work, we use MLA in an astrophysical context; our goal is to measure the mean longitudinal…
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…
A number of polarization estimators have been developed for a variety of astrophysical applications to compensate measurements of linear polarization for a bias contributed by the instrumental noise. Most derivations of the estimators…
Magnetic fields on the surface of the Sun and stars in general imprint or modify the polarization state of the electromagnetic radiation that is leaving from the star. The inference of solar/stellar magnetic fields is performed by…
The Helioseismic and Magnetic Imager (HMI), on board the Solar Dynamics Observatory (SDO), will begin data acquisition in 2008. It will provide the first full disk, high temporal cadence observations of the full Stokes vector with a 0.5 arc…
The accuracy of Milne-Eddington (ME) inversions, used to retrieve the magnetic field vector, depends upon the signal-to-noise ratio (SNR) of the spectro-polarimetric observations. The SNR in real observations varies from pixel to pixel,…
The spectral line polarization encodes a wealth of information about the thermal and magnetic properties of the solar atmosphere. Modeling the Stokes profiles of strong resonance lines is, however, a complex problem both from the…
Magnetic fields have important or dominant effects in many areas of astrophysics, but have been very difficult to quantify. Spectropolarimetry from Ground State Alignment (GSA) has been suggested as a direct tracer of magnetic field in…
Microlensing is a powerful tool for studying stellar atmospheres because as the source crosses regions of formally infinite magnification (caustics) the surfaceof the star is resolved, thereby allowing one to measure the radial intensity…
On the basis of Stokes parameter calculations for the Fe I 524.7 and 525.0 nm lines and the Holweger-Muller model atmosphere, the effect of the anomalous dispersion on solar magnetic field measurements by the line-ratio method is analyzed.…
Linearly polarized emission is described, in general, in terms of the Stokes parameters $Q$ and $U$, from which the polarization intensity and polarization angle can be determined. Although the polarization intensity and polarization angle…
Based on the Meso-Structured Magnetic Atmosphere (MESMA) approximation, recently introduced by Carroll & Kopf (2007), we present first results of an inversion of spectropolarimetric observations obtained from solar internetwork regions. To…
The polarization of light is a critically under-utilized, rich source of information in astronomy. For stars in particular, surface magnetism polarization that can be detected and measured with spectro-polarimetry. Many questions about…
We study the statistical properties of interstellar dust polarization at high Galactic latitude, using the Stokes parameter Planck maps at 353 GHz. Our aim is to advance the understanding of the magnetized interstellar medium (ISM), and to…
The multislice method, which simulates the propagation of the incident electron wavefunction through a crystal, is a well-established method for analyzing the multiple scattering effects that an electron beam may undergo. The inclusion of…