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In a microlensing event, a large magnification occurs at caustic crossing and provides an opportunity to obtain a stronger signal associated with the object. In this paper we study the possibility of magnetic field detection in a…

Solar and Stellar Astrophysics · Physics 2015-08-04 Ahmad Mehrabi , Habib khosroshahi , Hadi Rahmani

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

In order to get a significant Zeeman signature in the polarised spectra of a magnetic star, we usually 'add' the contributions of numerous spectral lines; the ultimate goal is to recover the spectropolarimetric prints of the magnetic field…

An effective-medium theory is proposed for random weakly nonlinear dielectric media. It is based on a new gaussian approximation for the probability distributions of the electric field in each component of a multi-phase composite. These…

Materials Science · Physics 2008-04-17 Yves-Patrick Pellegrini

Given that dynamically significant magnetic fields in at least some massive stars have now been measured, our contribution addresses the question, to what extent can fields be directly detected in circumstellar gas? The question speaks…

Astrophysics · Physics 2007-08-20 Richard Ignace , Kenneth G. Gayley

An understanding of how input parameter uncertainty in the numerical simulation of physical models leads to simulation output uncertainty is a challenging task. Common methods for quantifying output uncertainty, such as performing a grid or…

Materials Science · Physics 2023-09-25 Samuel G. McCallum , James E. Lerpiniére , Kjeld O. Jensen , Alison B. Walker

The degree to which the formation and evolution of clouds and filaments in the interstellar medium is regulated by magnetic fields remains an open question. Yet the fundamental properties of the fields (strength and 3D morphology) are not…

Astrophysics of Galaxies · Physics 2020-10-21 Stefan Reissl , Amelia M. Stutz , Ralf S. Klessen , Daniel Seifried , Stefanie Walch

Multiline techniques assuming similar line profiles have become a standard tool in stellar astronomy for increasing the signal-to-noise ratio (SNR) of spectropolarimetric measurements. However, due to the widely-used weak field…

Solar and Stellar Astrophysics · Physics 2010-03-29 C. Sennhauser , S. V. Berdyugina

The real part of the weak value is identified as the conditional Bayes probability through the quantum analog of the Bayes relation. We present an explicit protocol to get the the weak values in a simple Mach-Zehnder interferometer model…

Quantum Physics · Physics 2015-09-25 Akio Hosoya

One of the difficulties with performing polarization analysis is that the mean polarization fraction of sub-divided data sets is larger than the polarization fraction for the integrated measurement. The resulting bias is one of the…

Instrumentation and Methods for Astrophysics · Physics 2018-07-18 Victor Mikhalev

Marginalization techniques are presented for the Bayesian filtering problem under the assumption of Gaussian priors and posteriors and a set of sequentially more constraining state space model assumptions. The techniques provide the…

Statistics Theory · Mathematics 2016-07-12 John-Olof Nilsson

Numerical simulations of magneto-convection and analysis of solar magnetogram data provide empirical probability density functions (PDFs) for the line-of-sight component of the magnetic field. In this paper, we theoretically explore effects…

Solar and Stellar Astrophysics · Physics 2010-03-24 M. Sampoorna

The application of Bayesian inference for the purpose of model selection is very popular nowadays. In this framework, models are compared through their marginal likelihoods, or their quotients, called Bayes factors. However, marginal…

Methodology · Statistics 2022-07-27 F. Llorente , L. Martino , E. Curbelo , J. Lopez-Santiago , D. Delgado

We study the gravitational lensing in the weak field approximation assuming the presence of a plasma and of a magnetic field around a compact gravitational source. The external magnetic field causes the split of the image, as the…

General Relativity and Quantum Cosmology · Physics 2020-02-19 Bobur Turimov , Bobomurat Ahmedov , Ahmadjon Abdujabbarov , Cosimo Bambi

The polarization observed in the spectral lines of the He I 10830 multiplet carries valuable information on the dynamical and magnetic properties of plasma structures in the solar chromosphere and corona, such as spicules, prominences,…

Astrophysics · Physics 2008-11-26 J. Trujillo Bueno , A. Asensio Ramos

The observation of the polarization emerging from a rotating star at different phases opens up the possibility to map the magnetic field in the stellar surface thanks to the well-known Zeeman Doppler Imaging. When the magnetic field is…

Solar and Stellar Astrophysics · Physics 2015-06-05 M. J. Martínez González , A. Asensio Ramos

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 weak field approximation (WFA) is a conceptually simple and computationally light method for inferring the magnetic field strength and its orientation in the Sun's atmosphere. In this work we study the validity and limitations of this…

Solar and Stellar Astrophysics · Physics 2018-11-09 Rebecca Centeno

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

We investigate solution methods for large-scale inverse problems governed by partial differential equations (PDEs) via Bayesian inference. The Bayesian framework provides a statistical setting to infer uncertain parameters from noisy…

Applications · Statistics 2023-02-08 Mina Karimi , Mehrdad Massoudi , Kaushik Dayal , Matteo Pozzi