Talks by Dimitrios Psaltis

GPU-accelerated Ray Tracing and a Null Hypothesis Test of GR with the EHT

Dimitrios Psaltis University of Arizona
The supermassive black hole in the centre of the Milky Way, Sgr A*, is an ideal target for testing the properties of black holes. A number of experiments are being prepared or conducted, such as the monitoring of stellar orbits, the search for radio pulsars or the recording of an image of the shadow of a event horizon. The talk puts these efforts in context with other tests of general relativity and its alternatives.

Exploiting the Strong Gravitational Fields of Neutron Stars to Measure their Properties

Dimitrios Psaltis University of Arizona
Neutron stars possess the strongest gravitational fields among stellar objects in the Universe that are not surrounded by a horizon. This causes the emission from their surfaces to be strongly lensed and deformed. Two upcoming space X-ray missions, ESA's LOFT and NASA's NICER, aim to use observations of lightcurves from spinning neutron stars to map their gravitational fields as well as measure their masses and radii. In this talk, I will discuss some unexpected strong-field phenomena that affect gravitational lensing in the vicinity of neutron stars.