Learning the early universe: How 21cm cosmology leverages modern machine learning, Yannic Pietschke

by Mr Yannic Pietschke (Heidelberg University)

Tuesday 11 Nov 2025, 10:00 → 11:00 Europe/Vienna

Cosmic Dawn and the Epoch of Reionization mark the birth of the first stars and galaxies, whose radiation gradually ionized the intergalactic medium. These processes leave subtle imprints in the 21cm signal of neutral hydrogen, a direct tracer of the first cosmic structures. In this talk, I will introduce the physics behind the 21cm signal and why it is a key probe of this last phase transition.

I will then highlight how machine learning is transforming the way we study cosmic history. Using diffusion models, transformers, and normalizing flows, we can rapidly generate realistic 21cm data cubes, learn optimal data representations, and perform robust inference. This talk bridges physics and ML, showing how advanced data-driven methods are shedding light on the early Universe.

Zoom:

https://cern.zoom.us/j/65711657148?pwd=FeHu99rpPEJ3ScoxkP3apIEmgxSKyv.1

Meeting ID: 657 1165 7148
Passcode: 168650