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arXiv · 1001.1957

Relativistic redshift effects and the Galactic-center stars

Raymond Angélil·Prasenjit Saha
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Abstract

The high pericenter velocities (up to a few percent of light) of the S stars around the Galactic-center black hole suggest that general relativistic effects may be detectable through the time variation of the redshift during pericenter passage. Previous work has computed post-Newtonian perturbations to the stellar orbits. We study the additional redshift effects due to perturbations of the light path (what one may call "post-Minkowskian'' effects), a calculation that can be elegantly formulated as a boundary-value problem. The post-Newtonian and post-Minkowskian redshift effects are comparable: both are O(beta^3) and amount to a few km/s at pericenter for the star S2. On the other hand, the post-Minkowskian redshift contribution of spin is O(beta^5) and much smaller than the O(beta^4) post-Newtonian effect, which would be approximately 0.1km/s for S2.

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Raymond Angélil, Prasenjit Saha. 2010-01-12. Relativistic redshift effects and the Galactic-center stars. https://doi.org/10.1088/0004-637x%2F711%2F1%2F157

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