PT2 - Theory of light propagation in gravitation fields |
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Speaker |
Tsupko, Oleg |
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Coauthors |
Bisnovatyi-Kogan, Gennady S. |
| Talk Title |
Gravitational Lensing In Presence Of Plasma: Chromatic Lensing Indeed |
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Abstract |
We consider an influence of plasma on gravitational lensing. In presence of both gravity and plasma the deflection angle is physically defined by mutual combination of different phenomena: gravity, dispersion, refraction. While effects of deflection by gravity in vacuum and the refractive deflection in non-homogeneous medium are well known, the new effect is that in case of homogeneous plasma, in absence of refractive deflection, the gravitational deflection differs from vacuum deflection and depends on the photon frequency. In presence of non-homogeneity in plasma the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. For strong lens systems with multiple images, the presence of plasma leads to difference in angular position of the same image if observed at different wavelengths. Shift of angular position can be significant for observation in radio band. Gravitational lensing in plasma beyond weak deflection approximation is also considered. |
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