Dr. Bilal Ramzan visited to Superior University to give a public seminar talk on “Outflows from Galaxies” hosted and organized by ORIC Superior on 30th May 2022. The highlight of the seminar talk was about the behavior of the outflows of cosmic rays and radiation from the center of the galaxies. The details of the talk are mentioned as follows
Topic: "Outflows from Galaxies"
Presenter: Dr Bilal Ramzan
Venue: Superior University Lahore Gold Campus Main Raiwind Road
Organizers: ORIC Superior
Date: 30th May 2022
Abstract: Plasma outflow against a gravitational potential is usually referred to as a thermal outflow in galaxies. If thermal gas comes under the influence of cosmic rays, then we refer to them as cosmic ray accompanied outflows. We present a very interesting dependence of the cosmic ray diffusion coefficient on waves (Alfven Waves) in the context of hydrodynamics. There are two possible classes of outflows depending upon the suitably defined sound speed. One is subsonic outflows and the other one is supersonic. In the given figure, we show how different velocity and pressure profiles behave under the same set of boundary conditions. Thermal outflow and cosmic ray accompanied outflow look very similar. Quasi-thermal outflow looks similar to the other two types near the base, but somewhere along the flow waves become decoupled from the thermal gas and the flow becomes pure thermal outflow. Furthermore, we add nonlinear Landau damping effects on the different outflow profiles. This result is published in Ramzan et al. (2020), ApJ, 905, 117.
