Fakultät für Physik und Astronomie

Physikalisches Kolloquium am 18.12.2023: Vorträge zum Dissertationspreis

11.12.23 | Physikalisches Kolloquium, Veranstaltung

Am Montag (18.12.23) um 12.00 Uhr c.t. findet der nächste Termin unseres Physikalischen Kolloquiums statt.

An diesem Termin werden die beiden Kandidat*innen für den diesjährigen Dissertationspreis ihre Vorträge halten. Die Fakultät freut sich auf die Vorträge von Dr. Ancla Müller und Dr. Jan Luca van den Busch.

In the past decades, ram pressure has been found to be one of the most important mechanism to regulate the gas content of galaxies in the Universe. On larger scales of several hundred kiloparsecs, the outflows of active galactic nuclei can be bent. On smaller galaxy-size scales, the same effect can strip gas from individual galaxies and form debris downstream potentially showing in-situ star-formation. Despite the fact that galaxy star-formation is quenched over larger time-scales due to gas being removed by ram-pressure stripping, the galaxy can undergo a phase of very active star formation in between. On both scales, the role of magnetic fields and their influence on the physical processes have been barely studied.
In my PhD thesis, I have investigated for the very first time the magnetic field configuration in a ram-pressure stripped galaxy, where the derived parameters were used to restrict appropriate MHD-simulations. Observation and simulation agreed on a common model demonstrating the gas distribution of the multi-phase debris. On larger scales these unique observations are used to study the effect of ram pressure onto the lifetime of cosmic-ray particles by investigating re-acceleration processes.
On both scales the study of magnetic fields has revealed its importance with regard to the galaxy and galaxy cluster evolution and has opened a new field of research concerning the understanding of the gas and particle contribution in those environments.

Abstract Vortrag Dr. Ancla Müller


Modern cosmology depends heavily on studying the large scale distribution of matter, which allows us to get a better understanding of the physics of the universe. Most of the observations however consist of imaging data, which restricts us to a two-dimensional view. The reconstruction of the third dimension, the distance or redshift, is therefore a key challenge and potential systematic for cosmological studies. In this talk I present how we approached this issue for the gravitational lensing data of the Kilo-Degree Survey. We calibrate the redshift distribution of the observed galaxies with two independent methods and verify our results with realistic, simulated datasets. This allows us to confirm the previously reported tension between cosmological parameter constraints obtained from weak gravitational lensing and the early universe from measurements of the cosmic microwave background.

Abstract Vortrag Dr. Jan Luca van den Busch


Die Einführung erfolgt durch Prof. Dr. Hendrik Hildebrandt.

Die Fakultät lädt alle Interessierten herzlich ein. Die Veranstaltung findet im Hörsaal HZO 20 statt. Vor dem Kolloquium bieten wir Ihnen Kaffee und Kekse an.  

Alle Termine des Physikalischen Kolloquiums finden Sie hier.

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