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If stars at the lower end of the main sequence are responsible for the microlensing events observed in the Galactic bulge, then light from the lensing star contributes to the observed brightness. The background and lensing stars generally…

Astrophysics · Physics 2009-10-22 Marc Kamionkowski

Here, we revisit the polarization signal in caustic-crossing binary microlensing and introduce the maps of the polarization signals of the source star as a function of its position projected on the lens plane. The behavior of these maps…

Instrumentation and Methods for Astrophysics · Physics 2019-06-05 Sedighe Sajadian

We investigate the microlensing effects on a source star surrounded by a circumstellar disk, as a function of wavelength. The microlensing light curve of the system encodes the geometry and surface brightness profile of the disk. In the…

Astrophysics · Physics 2009-11-13 Zheng Zheng , Brice Ménard

We calculate the degree of linear polarization of radiation from stars having planets that may not be resolved spatially. We assume single scattering by water and silicate particulates in the planetary atmosphere. The dilution of the…

Astrophysics · Physics 2009-11-13 Sujan Sengupta , Malay Maiti

During some gravitational lensing events, the lens transits the face of the star. This causes a shift in the apparent radial velocity of the star which is proportional to its rotation speed. It also changes the magnification relative to…

Astrophysics · Physics 2009-10-28 Andrew Gould

A fraction of the light observed from edge-on disk galaxies is polarized due to two physical effects: selective extinction by dust grains aligned with the magnetic field, and scattering of the anisotropic starlight field. Since the…

Instrumentation and Methods for Astrophysics · Physics 2021-01-20 Chien-Hao Lin , Brent Tan , Rachel Mandelbaum , Christopher M. Hirata

We estimate the effects of weak lensing by large-scale density inhomogeneities and long-wavelength gravitational waves upon the polarization properties of electromagnetic radiation as it propagates from cosmologically distant sources.…

Astrophysics · Physics 2009-10-30 Gabriela C. Surpi , Diego D. Harari

We present a quantitative analysis of the effect of microlensing caused by random motion of individual stars in the galaxy which is lensing a background quasar. We calculate a large number of magnification patterns for positions of the…

Astrophysics · Physics 2016-08-30 Joachim Wambsganss , Tomislav Kundic

Polarization observations of radio pulsars show that abrupt transitions in the polarization vector's position angle can be accompanied by large excursions in the vector's ellipticity angle, suggesting the vector passes near the right or…

High Energy Astrophysical Phenomena · Physics 2024-08-20 M. M. McKinnon

We simulate the astrometric observations of stars moving close to the black hole in the Galactic Center. We show, that for orbits =<1000 AU and position measurements with the accuracy of the Keck Interferometer, the periastron motion of…

Astrophysics · Physics 2007-05-23 M. Jaroszynski

Polarization in stars was first predicted by Chandrasekhar [1] who calculated a substantial linear polarization at the stellar limb for a pure electron-scattering atmosphere. This polarization will average to zero when integrated over a…

Solar and Stellar Astrophysics · Physics 2018-04-19 Daniel V. Cotton , Jeremy Bailey , Ian D. Howarth , Kimberly Bott , Lucyna Kedziora-Chudczer , P. W. Lucas , J. H. Hough

We consider the effects induced by the presence of hot and cold spots on the source star in the light curves of simulated microlensing events due to either single or binary lenses taking into account the rotation of the source star and the…

Solar and Stellar Astrophysics · Physics 2017-03-23 Mosè Giordano , Achille A. Nucita , Francesco De Paolis , Gabriele Ingrosso

The high gradient of magnification across the source during both small impact parameter events and caustic crossings offers a unique opportunity for determining the surface brightness profile of the source. Furthermore, models indicate that…

Astrophysics · Physics 2010-04-08 R. Ignace , J. E. Bjorkman , H. M. Bryce

We consider the polarization arising from scattering in an envelope illuminated by a central anisotropic source. Spherical harmonics are used to describe both the light source anisotropy and the envelope density distribution functions of…

Astrophysics · Physics 2008-12-16 R Ignace , M Al-Malki , J Simmons , J C Brown , D Clarke , J Carson

Polarization is a basic property of light and is fundamentally linked to the internal geometry of a source of radiation. Polarimetry complements photometric, spectroscopic, and imaging analyses of sources of radiation and has made possible…

Instrumentation and Methods for Astrophysics · Physics 2017-01-18 S. Trippe

This study investigates the polarization characteristics of solitonic boson stars surrounded by a thin accretion disk. By comparing their polarization images with corresponding optical images, we find a positive correlation between the…

General Relativity and Quantum Cosmology · Physics 2025-08-19 Xiao-Xiong Zeng , Chen-Yu Yang , Hao Yu , Ke-Jian He

The integrated spectrum of OH emission from late-type stars is often circularly polarized, by as much as 50% in some cases. While the spectra are partially polarized, the individual maser components revealed by VLBI are much more so. Using…

Astrophysics · Physics 2009-10-31 Stacy Palen

I model the effect of rapid stellar rotation on a planet's insolation. Fast-rotating stars have induced pole-to-equator temperature gradients (known as gravity-darkening) of up to several thousand Kelvin that affect the star's luminosity…

Earth and Planetary Astrophysics · Physics 2016-12-07 John P. Ahlers

The effect of stars on the lensing properties of the supermassive black hole in the Galactic Center is similar to the effect of planets on microlensing by a star. We show that the dense stellar cluster around SgrA* increases by factors of a…

Astrophysics · Physics 2009-10-31 Tal Alexander , Abraham Loeb

Extended source size effects have been detected in photometric monitoring of gravitational microlensing events. We study similar effects in the centroid motion of an extended source lensed by a point mass. We show that the centroid motion…

Astrophysics · Physics 2015-06-24 Shude Mao , Hans J. Witt