My name is Vojtěch Witzany and I work at Charles U. Prague. I used to contribute here more, and you will see both questions and answers starting from my graduate studies here.
My area of research is classical relativistic gravity and I also dabble in relativistic astrophysics. You can check out my research papers on ArXiv or my personal webpage if you are interested in details.
The profile picture is a snapshot of a magneto-hydrodynamic simulation of accretion onto a black hole from this paper.