Speaker
Description
In this talk, I will present a systematic investigation into the connection between galaxy morphology and the properties of their host dark-matter halos using the IllustrisTNG-50 simulations.
I will briefly introduce a novel kinematic decomposition method that builds upon existing algorithms but features simple yet physical identification of different morphological components. This new method enables robust separation of thin and thick galactic discs. Importantly, the circularity threshold defining thin discs and the energy threshold separating dynamically hotter and colder galaxy regions both depend systematically on halo mass and environment. Applying this method to TNG50, I revisit the question which halo structural parameters constitute the best predictor for disc size, and find that halo spin, halo concentration and accretion rate all impact disc size for a given halo mass, challenging widely used semi-analytical recipes that predict disk size solely on the spin parameter. Employing Random Forest and Symbolic Regression, I predict galaxy morphologies with additional halo parameters. Preliminary results reveal empirical formulae predicting disc mass fractions, half-mass radii, and half-mass heights, with accuracy higher than other commonly used relations, which is super promising in the future semi-analytical models.
