412 citations · 3.1k across the 30 of their papers we have counts for
4 papers · 1 filter
A Metric for Testing the Nature of Black Holes
Tim Johannsen
In general relativity, astrophysical black holes are uniquely described by the Kerr metric. Observational tests of the Kerr nature of these compact objects and, hence, of general r…
Testing General Relativity in the Strong-Field Regime with Observations of Black Holes in the Electromagnetic Spectrum
Tim Johannsen
General relativity has been tested by many experiments, which, however, almost exclusively probe weak spacetime curvatures. In this thesis, I create two frameworks for testing gene…
Testing the No-Hair Theorem with Observations in the Electromagnetic Spectrum. IV. Relativistically Broadened Iron Lines
Tim Johannsen, Dimitrios Psaltis
According to the no-hair theorem, astrophysical black holes are fully characterized by their masses and spins and are described by the Kerr metric. This theorem can be tested obser…
Masses of Nearby Supermassive Black Holes with Very-Long Baseline Interferometry
Tim Johannsen, Dimitrios Psaltis, Stefan Gillessen +4
Dynamical mass measurements to date have allowed determinations of the mass M and the distance D of a number of nearby supermassive black holes. In the case of Sgr A*, these measur…