Welcome! 

The Section of Astrophysics, Astronomy and Mechanics of the Department of Physics of the National and Kapodistrian University of Athens offers a series of virtual Colloquia in Astrophysics that started in October 2020. 

For more information about the academic staff and the research activities of our Section, click here.

26ear friends,

We are happy to announce the 2024 Spring Astrophysics Seminars Series . Our seminars will start on April 3, 2024 and will continue till June 26, 2024. 

Date and Time:  26 June 2024, 4pm (9 am EST) *in person*

Speaker: Prof. Bart Ripperda (Canadian Institute for Theoretical Astrophysics at the University of Toronto, Canada)

Title: How black holes accrete and eject

Abstract:  Astrophysical black holes are surrounded by accretion disks, jets, and coronae consisting of magnetized relativistic plasma. They produce observable high-energy radiation from nearby the event horizon and it is currently unclear how this emission is exactly produced. The radiation typically has a non-thermal component, implying a power-law distribution of emitting relativistic electrons. Magnetic reconnection and plasma turbulence are viable mechanisms to tap the large reservoir of magnetic energy in these systems and accelerate electrons to extreme energies. The accelerated electrons can then emit high-energy photons that themselves may strongly interact with the plasma, rendering a highly nonlinear system. Modeling these systems necessitates a combination of magnetohydrodynamic models to capture the global dynamics of the formation of dissipation regions, and a kinetic treatment of plasma processes that are responsible for particle acceleration, quantum electrodynamics effects like pair creation and annihilation, and radiation. I will present novel studies of accreting black holes and how they radiate in regions close to black hole event horizon, using both first-principles general relativistic kinetic particle-in-cell simulations and global large-scale three-dimensional magnetohydrodynamics models. With a combination of models, I determine where and how dissipation of magnetic energy occurs, what kind of emission signatures are typically produced, and what they can teach us about the nature of black holes.

We are looking forward to your participation!

You can also follow us on Facebook at Astro UoA Colloquia.

Image credit: WallpaperDog © 2021

Wednesdays at 6:00 PM (EET) - 5:00 PM (CET) - 11:00 AM (EST)

Note: In person colloquia will take place at 4:00 PM (EET) at the Seminar room of the Section of Astrophysics at NKUA.
Connection information:  https://us02web.zoom.us/j/87407934599?pwd=Q0lVRk55NXB6U2VsNTc2Nk9rbkkrdz09