Machine Learning and Cosmological Simulations II: Hydrodynamical Simulations

TL;DR

This paper demonstrates that machine learning can efficiently and accurately model galaxy formation and evolution using hydrodynamical simulations, providing a fast alternative to traditional methods.

Contribution

It extends previous ML frameworks to hydrodynamical simulations, showing that ML can predict key galaxy properties with high robustness using minimal input data.

Findings

ML models predict galaxy properties accurately from dark matter halo data

ML reproduces galaxy populations consistent with hydrodynamical simulations

ML achieves these results in minutes, significantly faster than traditional simulations

Abstract

We extend a machine learning (ML) framework presented previously to model galaxy formation and evolution in a hierarchical universe using N-body + hydrodynamical simulations. In this work, we show that ML is a promising technique to study galaxy formation in the backdrop of a hydrodynamical simulation. We use the Illustris Simulation to train and test various sophisticated machine learning algorithms. By using only essential dark matter halo physical properties and no merger history, our model predicts the gas mass, stellar mass, black hole mass, star formation rate, $g-r$ color, and stellar metallicity fairly robustly. Our results provide a unique and powerful phenomenological framework to explore the galaxy-halo connection that is built upon a solid hydrodynamical simulation. The promising reproduction of the listed galaxy properties demonstrably place ML as a promising and a significantly more computationally efficient tool to study small-scale structure formation. We find that ML mimics a full-blown hydrodynamical simulation surprisingly well in a computation time of mere minutes. The population of galaxies simulated by ML, while not numerically identical to Illustris, is statistically and physically robust and follows the same fundamental observational constraints. Machine learning offers an intriguing and promising technique to create quick mock galaxy catalogs in the future.