Time Dilation of Observers in Schwarzschild de Sitter Spacetime

Presenter

Allison Powell

Campus

UMass Amherst

Sponsor

Jennie Traschen, Department of Physics, UMass Amherst

Schedule

Session 4, 2:30 PM - 3:15 PM [Schedule by Time][Poster Grid for Time/Location]

Location

Poster Board A17, Campus Center Auditorium, Row 1 (A1-A20) [Poster Location Map]

Abstract

We analyze the timelike geodesics of circular and radial orbits in Schwarzschild de Sitter spacetime for zero, small, and large values of the cosmological constant as well as null geodesics for large cosmological constant.  We also find a static geodesic orbit which can happen in Schwarzschild de Sitter but not with zero cosmological constant.  The circular orbits are found by identifying local maxima and minima in the derivative of the potential which is calculated from setting the scalar product of the 4 velocity to -1 in the timelike case and zero in the null case.  We approximate the case of small cosmological constant as a perturbation of the Schwarzschild case to find an initial guess for the radius of circular orbits, and use the Newton-Raphson method to find a more accurate result.  We calculate the time dilation between infalling observers and orbiting as well as radial, geodesic observers. 

Keywords

astrophysics, black hole, Schwarzschild de Sitter space

Research Area

Astronomy, Cosmology, and Astrophysics

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