Frequency-dependent effects of gravitational lensing within plasma
By A. Rogers. 2015
154 citations recorded by the source corpus.
The interaction between refraction from a distribution of inhomogeneous plasma and gravitational lensing introduces novel effects to the paths of light rays passing by a massive object. The plasma contributes additional terms to the equations of motion, and the resulting ray trajectories are frequency–dependent. Lensing phenomena and circular orbits are investigated for plasma density distributions N / 1/r h with h � 0 in the Schwarzschild space–time. For rays passing by the mass near the plasma frequency refractive effects can dominate, effectively turning the gravitational lens into a mirror. We obtain the turning points, circular orbit radii, and angular momentum for general h. Previous results have shown that light rays behave like massive particles with an effective mass given by the plasma frequency for a constant density h = 0. We study the behaviour for general h and show that when h = 2 the plasma term acts like an additional contribution to the angular momentum of the passing ray. When h = 3 the potential and radii of circular orbits are analogous to those found in studies of massless scalar fields on the Schwarzschild background. As a physically motivated example we study the pulse profiles of a compact object with antipodal hotspots sheathed in a dense plasma, which shows dramatic frequency–dependent shifts from the behaviour in vacuum. Finally, we consider the potential observability and applications of such frequency–dependent plasma effects in general relativity for several types of neutron star.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/0eb69fa44fb5fc120737c1941362c03dea4fd766
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In Astronomy and Astrophysics
In Nuclear and High Energy Physics
Citations in the corpus
- Gravitational Lensing in Presence of Plasma: Strong Lens Systems, Black Hole Lensing and Shadow (2017, background): “As a relevant physical example the propagation of radiation emitted from a compact object sheathed in a dense plasma had been examined [49].”