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We use a 3D Monte Carlo radiative transfer code to study the polarimetric and photometric variability from stationary corotating interaction regions (CIR) in the wind of massive stars. Our CIRs are approximated by Archimedean spirals of…

Solar and Stellar Astrophysics · Physics 2019-09-25 Danny Carlos-Leblanc , Nicole St-Louis , Jon Bjorkman , Richard Ignace

Magnetic fields in turbulent, convective high-$\beta$ plasma naturally develop highly tangled and complex topologies---the solar photosphere being the paradigmatic example. These fields are mostly undetectable by standard diagnostic…

Using Monte-Carlo simulations of X-ray flare distributions across the accretion disk of active galactic nuclei (AGN), we obtain modeling results for the energy-dependent fractional variability amplitude. Referring to previous results of…

Astrophysics · Physics 2007-05-23 R. W. Goosmann , M. Dovciak , V. Karas , B. Czerny , M. Mouchet , G. Ponti

The coplete analysis of the model-independent leading radiative corrections to cross-section and polarization observables in semi-inclusive deep-inelastic electron-nucleus scattering with detection of a proton and scattered electron in…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. V. Afanas'ev , I. Akushevich , G. I. Gakh , N. P. Merenkov

Optical spectropolarimetry and broadband polarimetry in other wavebands has been a key to understanding many diverse aspects of AGN. In some cases polarization is due to synchrotron radiation, and in other cases it's due to scattering.…

Astrophysics · Physics 2007-05-23 R. R. J. Antonucci

We present results of radiative transfer calculations of Compton scattering of polarized radiation in a corona above an accretion disk. The corona has a plane-parallel geometry and is assumed to be homogeneous with a fixed temperature. We…

Astrophysics · Physics 2009-10-30 Chia-ming Hsu , Omer Blaes

We performed a least-square fit analysis to reproduce the elastic angular distributions for $\alpha$ scattering on various nuclei form $^{12}$C to $^{208}$Pb for incident energies in the range 18 - 70 MeV using a velocity-dependent optical…

Nuclear Theory · Physics 2024-04-16 A. Saleh , M. I. Jaghoub

Polars (or AM Her systems) are cataclysmic variables without a disc due to the strong magnetic field of the white dwarf. Most of their emission comes from the region where the accretion column impacts the white dwarf and cools through…

Solar and Stellar Astrophysics · Physics 2009-09-08 J. E. R. Costa , C. V. Rodrigues

We model the expected X-ray polarisation induced by complex reprocessing in the active nucleus of the Seyfert-2 galaxy NGC 1068. Recent analysis of infrared interferometry observations suggests that the ionised outflows ejected by the…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Rene W. Goosmann , Giorgio Matt

Light scattered off particles can become linearly polarized. Stars surrounded by oblique, co-rotating envelopes are therefore expected to manifest periodic linear polarimetric variations. The electron scattering magnetospheres of magnetic…

Solar and Stellar Astrophysics · Physics 2022-01-05 M. S. Munoz , G. A. Wade , D. M. Faes , A. C. Carciofi , J. Labadie-Bartz

In this first research note of a series of two, we conduct optical/UV investigations of the spectropolarimetric signatures emerging from the structure of quasars (Elvis 2000) applied to a purely theoretical, dusty model. We aim to explore…

High Energy Astrophysical Phenomena · Physics 2013-10-08 F. Marin , R. W. Goosmann

We present the results of our spectropolarimetric observations for a number of active galactic nuclei (AGNs) carried out at the 6-m telescope with the SCORPIO focal reducer. The derived wavelength dependences of the polarization have been…

Astrophysics of Galaxies · Physics 2011-04-20 V. L. Afanasiev , N. V. Borisov , Yu. N. Gnedin , T. M. Natsvlishvili , M. Yu. Piotrovich , S. D. Buliga

We examine manifestations of neutron electromagnetic polarizabilities in coherent Compton scattering from the Helium-3 nucleus. We calculate $\gamma ^3$He elastic scattering observables using chiral perturbation theory to next-to-leading…

Nuclear Theory · Physics 2018-04-06 Deepshikha Choudhury , Andreas Nogga , Daniel R. Phillips

To explain the broad-band spectral energy distributions (SED) of Seyfert nuclei and QSOs, we study the emission spectrum emerging from a vertical disk-corona structure composed of a two-temperature plasma by solving hydrostatic equilibrium…

Astrophysics · Physics 2009-10-31 T. Kawaguchi , T. Shimura , S. Mineshige

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

Neutron stars serve as unique laboratories for studying ultra-dense nuclear matter. The equation of state of neutron star matter can be effectively constrained by their masses and radii. Particular attention has been paid to rapidly…

High Energy Astrophysical Phenomena · Physics 2026-03-24 Wenda Zhang , Wenfei Yu

The central regions of galaxies harbouring active galactic nuclei (AGNs) can be quite complex, especially at high activity, presenting, besides variability, a variety of phenomena related, e.g. to ionization/excitation mechanisms. A…

In these notes we present a detailed and complete scheme for the calculation of polarization phenomena in elastic electron-nucleon scattering. The longitudinal and transversal components of the polarization for the scattered nucleon,…

Nuclear Theory · Physics 2007-05-23 Michail P. Rekalo , Egle Tomasi-Gustafsson

Even when the direct view toward the active nucleus is obscured, nuclear emission propagating along other directions can scatter off surrounding material, become polarized and reach the observer. Spectropolarimetry can thus be an important…

Astrophysics of Galaxies · Physics 2023-09-06 Nadia L. Zakamska , Rachael M. Alexandroff

Aims: Main goal of this work is to study the potential of He II Ly-alpha wavelength-integrated scattering polarisation for probing the magnetism of the solar upper chromosphere. Methods: Radiative transfer calculations are performed in…

Solar and Stellar Astrophysics · Physics 2024-08-14 F. Riva , G. Janett , L. Belluzzi
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