halogal
halogal is a public Python package for studying the connection between galaxies and their dark matter halos — a core topic of my research program. The code is openly available on GitHub and designed to be useful to the broader community.
Overview
The galaxy–halo connection is a central thread in modern extragalactic astrophysics: every galaxy forms and evolves within a dark matter halo, and understanding how baryonic properties map onto the underlying halo population is key to both galaxy formation physics and cosmological inference.
halogal provides tools to quantify and model this connection from observational data, with a focus on:
- Stellar-to-halo mass relations (SHMR)
- Halo occupation distributions (HOD)
- Abundance matching and related empirical techniques
- Integration with deep photometric survey catalogs (including COSMOS)
The package is written in Python and built with reproducibility and community reuse in mind.
Repository
Scientific Context
My work on galaxy–halo connection draws on deep photometric surveys such as COSMOS2020 and COSMOS2025 to build large statistical samples of galaxies with accurate photometric redshifts and stellar masses. By combining these with N-body simulations and halo catalogs, halogal enables constraints on how galaxies populate their halos across cosmic time.
Key results include measurements of the SHMR and its evolution with redshift, connecting back to fundamental questions about feedback, quenching, and the efficiency of star formation in halos of different masses.
Related Publications
For the science that motivates and uses this code, see the Publications page.
Contributions, issues, and pull requests are welcome on GitHub.