February 21, 2023
Speaker: Christoph Pfrommer (Leibniz-Institute for Astrophysics Potsdam)
Contact Information: cpfrommer@aip.de
Title: Cosmic ray feedback and magnetic dynamos in galaxy formation
Abstract: Understanding the physics of galaxy formation is an outstanding problem in modern astrophysics. Recent cosmological simulations have demonstrated that feedback by star formation, supernovae and active galactic nuclei appears to be critical in obtaining realistic disk galaxies and to slow down star formation to the small observed rates. However the particular physical processes underlying these feedback processes still remain elusive. In particular, many of these simulations neglected magnetic fields and relativistic particle populations (so-called cosmic rays). Those are known to provide a pressure support comparable to the thermal gas in our Galaxy and couple dynamically and thermally to the gas, which seriously questions their neglect. After introducing the underlying physical concepts, I will present our recent efforts to model cosmic ray physics and magnetic fields in galaxy formation. In particular, I will explain how cosmic rays interact with and propagate through the magnetized plasma in the interstellar and circumgalactic media and how we can observationally test these theoretical considerations using new high-sensitivity MeerKAT observations. I will then demonstrate that cosmic rays play a decisive role in the formation and evolution of spiral galaxies by providing feedback that regulates star formation and drives gas out in galactic winds. Comparing cosmic ray spectra of electrons and protons to observational data and studying the correlation of the far-infrared emission with the gamma-ray and radio emission from galaxies enables us to test the cosmic ray feedback and dynamo models for the growth of galactic magnetic fields. This argues that a complete understanding of galaxy formation necessarily includes these non-thermal components.
Visitor's room: Room 111A
Visit Schedule:
Tuesday (21 Feb. 2023):
9:30 a.m.: Philipp Kempski
10:00 a.m: Matt Sampson
10:30 a.m.:
11:00 a.m.: Colloquium
11:30 a.m.: Colloquium
12:00 p.m.: Bahcall lunch
12:30 p.m.: Bahcall lunch
1:00 p.m.: Bahcall lunch
1:30 p.m.: Christopher Bambic
2:00 p.m.: Tea Time with Grad Students in Grand Central
2:30 p.m.:Tea Time with Grad Students in Grand Central
3:00 p.m.: Weekly discussion on Computational Astrophysics w/ Romain Teyssier [Sanghyuk Moon: Mon 10am]
3:30 p.m.: Weekly discussion on Computational Astrophysics w/ Romain Teyssier [Matthew Kunz: Thu 10am]
4:00 p.m.: Muni Zhou
4:30 p.m.: Arno Vanthieghem
5:00 p.m.: Eve Ostriker (Peyton 136)
Dinner Sign-up - add your name here:
Tuesday (21 Feb. 2023).
We have a reservation at Agricola for 6:15pm. We will walk from Peyton, leaving at 5:55.
Faculty Host: Eve Ostriker
Postdoc Host: Arno Vanthieghem
Jens Mahlmann
Nora Linzer
Muni Zhou
Matt Sampson
Christopher Bambic
Romain Teyssier
STUDENTS HAVE PRIORITY.
PLEASE NO MORE THAN 8 PEOPLE (it is more difficult to properly interact with the speaker in larger groups).