Joonas Nättilä, Columbia University, CCA
When
Abstract: Space weather around neutron stars and black holes consists of spectacular fireworks---the most extreme plasma physics events in our universe. Neutron stars are compact stellar remnants with a radius of ~12km and a mass of ~1.5 times the mass of the Sun. They spin with periods from seconds to milliseconds and can sustain magnetic fields from 10^8 to 10^15 Gauss. Similarly, typical black holes have an event horizon radius of ~30km and a mass of ~10 times the mass of the Sun. They, too, have been measured to spin close to 95% of the speed of light and are surrounded by powerful magnetic fields of B > 10^6 Gauss. The dynamic magnetospheres around these compact objects are observed to generate intense millisecond-duration radio flashes and luminous X-ray flares. Understanding the physics of these cosmic bursts and flares is at the forefront of current research in plasma astrophysics.
In my talk, I will discuss the extreme plasma physics behind such fireworks and review our current efforts in modeling them. I will also discuss how our current first-principles radiative plasma physics simulations are finally starting to shed light on many of the phenomena mentioned above and how they can be used to constrain the plasm conditions around neutron stars and black holes in the near future.
Bio:
Dr. Joonas Nättilä is a computational astrophysicist studying cosmic plasmas around neutron stars and black holes. He is interested in all kinds of energetic, extreme, and explosive astrophysical phenomena. For his research, he uses both theoretical “pen-and paper work” and large-scale supercomputer simulations to understand the microphysics of astrophysical plasmas. He is the Principal Investigator of the European Research Council (ERC) funded 2.2MEUR research project ILLUMINATOR. The project aims to unravel how neutron stars generate their observed electromagnetic radiation. Nättilä is an Associate Professor of Astrophysics at the University of Helsinki. Before coming to Helsinki, he was an Associate Research Scientist at Columbia University in New
York and a Flatiron Research Fellow at the Center for Computational Astrophysics, Flatiron Institute. He obtained his Ph.D. from the University of Turku, Finland.
MEET THE SPEAKER: Contact the host, Mathieu Renzo or sign up on the invited speaker schedule
Reception: Refreshments at 3:00 PM, Kuiper Building, 3rd Floor Atrium
Live stream: Zoom Meeting ID: 417 674 3144 Passcode: 1985Astro
Watch later: TAP YouTube Channel