Populating Galaxies Into Halos Via Machine Learning on the Simba Simulation

Fuente: arXiv
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Autores principales: Das, Pratyush Kumar, Davé, Romeel, Cui, Weiguang
Formato: Preprint
Publicado: 2024
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author Das, Pratyush Kumar
Davé, Romeel
Cui, Weiguang
author_facet Das, Pratyush Kumar
Davé, Romeel
Cui, Weiguang
contents We present a machine-learning framework, Machine Inferred Galaxy (MIG), to populate dark-matter haloes with galaxies in N-body simulations. MIG predicts stellar mass ($M_\ast$), star-formation rate (SFR), atomic and molecular gas masses ($M_{\mathrm{HI}}$ and $M_{\mathrm{H_2}}$), and metallicity, and can be extended to other properties and simulations. The pipeline first separates haloes into centrals and satellites, then uses classifiers to distinguish star-forming (SF) from quenched (Q) systems, followed by regressors trained on the SF subsets for both centrals and satellites. Trained on the $(100,h^{-1},\mathrm{Mpc})^3$ SIMBA galaxy-formation simulation at $z=0$, MIG achieves high accuracy for key baryonic properties (e.g. $R^2 \approx 0.9$ for $M_{\mathrm{HI}}$ of central galaxies), and remains robust at $z=1$ and $z=2$. Training on fractional quantities (e.g. $M_{\mathrm{HI}}/M_\ast$) and rescaling by predicted $M_\ast$ improves performance over direct predictions across properties and redshifts. MIG also reproduces galaxy mass distribution functions with higher fidelity, enabling accurate predictions of integrated tracers such as H I intensity maps. MIG therefore provides an efficient, physically consistent route to generate mock galaxy catalogues and baryonic tracers in large cosmological volumes for upcoming surveys.
format Preprint
id arxiv_https___arxiv_org_abs_2406_16103
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Populating Galaxies Into Halos Via Machine Learning on the Simba Simulation
Das, Pratyush Kumar
Davé, Romeel
Cui, Weiguang
Astrophysics of Galaxies
We present a machine-learning framework, Machine Inferred Galaxy (MIG), to populate dark-matter haloes with galaxies in N-body simulations. MIG predicts stellar mass ($M_\ast$), star-formation rate (SFR), atomic and molecular gas masses ($M_{\mathrm{HI}}$ and $M_{\mathrm{H_2}}$), and metallicity, and can be extended to other properties and simulations. The pipeline first separates haloes into centrals and satellites, then uses classifiers to distinguish star-forming (SF) from quenched (Q) systems, followed by regressors trained on the SF subsets for both centrals and satellites. Trained on the $(100,h^{-1},\mathrm{Mpc})^3$ SIMBA galaxy-formation simulation at $z=0$, MIG achieves high accuracy for key baryonic properties (e.g. $R^2 \approx 0.9$ for $M_{\mathrm{HI}}$ of central galaxies), and remains robust at $z=1$ and $z=2$. Training on fractional quantities (e.g. $M_{\mathrm{HI}}/M_\ast$) and rescaling by predicted $M_\ast$ improves performance over direct predictions across properties and redshifts. MIG also reproduces galaxy mass distribution functions with higher fidelity, enabling accurate predictions of integrated tracers such as H I intensity maps. MIG therefore provides an efficient, physically consistent route to generate mock galaxy catalogues and baryonic tracers in large cosmological volumes for upcoming surveys.
title Populating Galaxies Into Halos Via Machine Learning on the Simba Simulation
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2406.16103