Analytische Methoden bei Gravitationslinsenphänomenen: Schatten Schwarzer Löcher

This doctoral thesis is about an analytic way to describe the shadow of black holes. As introduction, a survey of the attempts to observe the shadow of the black holes in our Galaxy near Sgr A* and in the neighbouring galaxy M87 is presented. Black holes are described by metrics of the general Plebanski-Demianski class of space-times. All these metrics are axially symmetric and stationary type D solutions to the Einstein-Maxwell equations with a cosmological constant. The space-times are characterized by seven parameters: mass, spin, electric and magnetic charge, gravitomagnetic NUT charge, a so-called acceleration parameter and the cosmological constant. Based on a detailed discussion of the metrics, analytical formulas are derived for the photon regions (regions that contain spherical lightlike geodesics) and for the boundary curve of the shadow as it is seen by an observer at given Boyer-Lindquist coordinates in the domain of outer communication. They make it possible to analyze the dependency of the shadow of a Kerr black hole on the motion of the observer. For all cases, the photon regions and shadows are visualized for various values of the parameters. The analytical formulas are used to find explicit expressions for the horizontal and vertical angular diameters of the shadow. Finally, these values are estimated for the black holes at the centers of our Galaxy and of M87

BOOST -- A Satellite Mission to Test Lorentz Invariance Using High-Performance Optical Frequency References

BOOST (BOOst Symmetry Test) is a proposed satellite mission to search for violations of Lorentz invariance by comparing two optical frequency references. One is based on a long-term stable optical resonator and the other on a hyperfine transition in molecular iodine. This mission will allow to determine several parameters of the standard model extension in the electron sector up to two orders of magnitude better than with the current best experiments. Here, we will give an overview of the mission, the science case and the payload.Comment: 11 pages, 2 figures, accepted for publication in Phys. Rev.

Analytical Methods for Gravitational Lensing Phenomena: Shadows of Black Holes

This doctoral thesis is about an analytic way to describe the shadow of black holes. As introduction, a survey of the attempts to observe the shadow of the black holes in our Galaxy near Sgr A* and in the neighbouring galaxy M87 is presented. Black holes are described by metrics of the general Plebanski-Demianski class of space-times. All these metrics are axially symmetric and stationary type D solutions to the Einstein-Maxwell equations with a cosmological constant. The space-times are characterized by seven parameters: mass, spin, electric and magnetic charge, gravitomagnetic NUT charge, a so-called acceleration parameter and the cosmological constant. Based on a detailed discussion of the metrics, analytical formulas are derived for the photon regions (regions that contain spherical lightlike geodesics) and for the boundary curve of the shadow as it is seen by an observer at given Boyer-Lindquist coordinates in the domain of outer communication. They make it possible to analyze the dependency of the shadow of a Kerr black hole on the motion of the observer. For all cases, the photon regions and shadows are visualized for various values of the parameters. The analytical formulas are used to find explicit expressions for the horizontal and vertical angular diameters of the shadow. Finally, these values are estimated for the black holes at the centers of our Galaxy and of M87

The shadow of black holes: an analytic description

This book introduces an analytic method to describe the shadow of black holes. As an introduction, it presents a survey of the attempts to observe the shadow of galactic black holes. Based on a detailed discussion of the Plebański–Demiański class of space-times, the book derives analytical formulas for the photon regions and for the boundary curve of the shadow as seen by an observer in the domain of outer communication. It also analyzes how the shadow depends on the motion of the observer. For all cases, the photon regions and shadows are visualized for various values of the parameters. Finally, it considers how the analytical formulas can be used for calculating the horizontal and vertical angular diameters of the shadow, and estimates values for the black holes at the centers of our Galaxy near Sgr A* and of the neighboring galaxy M87

BOOST: A Satellite Mission to Test Fundamental Physics

BOOST (BOOst Symmetry Test) is a proposed satellite mission to search for violations of Lorentz invariance using two frequency references. One is based on a long-term stable optical resonator and the other on a hyperfine Transition in molecular iodine. Here, we will give an overview of the mission and the payload