Theoretical astrophysics uses fundamental laws of physics, ranging from particle physics to gravitational theory, to investigate a wide variety of observable astronomical phenomena.
Professor Cowsik's research interest include astro-particle physics, mainly galactic dynamics of dark matter and itsdetection, especially at the interface of particle physics and cosmology,astrophysics of cosmic- ray, radio, x-ray, gamma-ray and neutrinosources like accreting neutron stars and black holes, supernova remnants,galaxies, active galactic nuclei and gamma ray bursts.
Professor Katz's work centers on gama-ray bursts, the most energetic explosions in the universe. These events appear to release as much energy as is contained in 1% of the rest mass of the Sun, and produce streams of matter moving outward at between 99.99% and 99.9999% of the speed of light.
Investigating the shocks that result when this fast and energetic stream collides with surrounding matter, or with other streams, Professor Katz was able to predict the low frequency asymptotic spectrum of the emitted radiation and the occurrence of radio and visible "after-glows" to gamma-ray bursts. The predicted spectrum has a spectral density proportional to the 1/3 power of the frequency, a result familiar from laboratory synchrotrons but never before seen in astronomical objects.
Professor Krawczynski studies the properties of the X-ray and gamma-ray emission from relativistic outflows (jets) from stellar mass and supermassive black holes. The work aims at understanding of how astrophysical black holes grow by accreting matter and how they impact their environment. More recently, Krawczynski evaluated tests of the theory of General Relativity in the strong gravity regime based on X-ray observations. Observations with current and upcoming NASA missions can be used to test General Relativity's No-Hair-Theorem that predicts that astrophysical black holes are described by the Kerr metric.