The Colloquium takes place every Wednesday at 11:15 AM - Warsaw Copernicus Astronomical Centre online by means of Zoom platform. The Colloquium is given in English and chaired by dr Stanisław Bajtlik (bajtlik@camk.edu.pl). People from outside of the Copernicus Center are very welcome to participate. For technical detailes please contact Dr. Stanislaw Bajtlik.
Oliver Porth (University of Amsterdam)
The time-variable (in particular pulsed-) emission from black holes and neutron stars holds key information on the nature of curved spacetime and ultra dense nuclear matter. However, due to the complex plasma dynamics at play, the interpretation of the observed signals is difficult. I will present some of our recent work on modeling general relativistic magnetohydrodynamic processes around black holes and accreting neutron stars. I will first discuss the dynamics of strongly perturbed black hole magnetospheres as they can occur for example during binary neutron star merger events. The simulations have revealed an intriguing rapid alignment of the magnetic moment and black hole spin which can uniquely imprint the high energy emission of the current sheet. I will further discuss the dynamics of multipolar black hole magnetospheres (Selvi et al. in prep). Switching gears, I will then discuss our recent 3D simulations of accreting neutron stars with oblique magnetospheres, focusing on the questions of jet formation and pulsed emission. The obtained X-ray pulse profiles are consistent in amplitude and harmonic content with the observations of AMXPs, however they also exhibit significant and rapid variability in hotspot temperature and shape due to the turbulent accretion flow.
Journal Club takes place on Mondays at 11:00 AM in the Seminar Room. The seminar is given in English and is chaired by Angelos Karakonstantakis, Gergely Hajdu, and Fatemeh Kayanikhoo.
