Insights into the dependence of galaxy properties on the environment with explainable machine learning models

Abstract

Galaxies reside within dark matter halos, but their properties are influenced not only by their halo properties but also by the surrounding environment. We construct an interpretable neural network framework to characterize the surrounding environment of galaxies and investigate the extent to which their properties are affected by neighboring galaxies in IllustrisTNG300 data ($z=0$). Our models predict galaxy properties (stellar mass and star formation rate) given dark matter subhalo properties of both host subhalo and of surrounding galaxies, which serve as an explainable, flexible galaxy-halo connection model. We find that prediction accuracy peaks when incorporating only the nearest neighboring galaxy for stellar mass prediction, while star formation rate prediction benefits from information from up to the third-nearest neighbor. We determine that environmental influence follows a clear hierarchical pattern, with the nearest neighbor providing the dominant contribution that diminishes rapidly with additional neighbors. We confirm that central and satellite galaxies, as well as different galaxy categories based on mass and star-forming activity, exhibit distinct environmental dependencies. Environmental dependence for low-mass galaxies ($\log (M_{\ast }/M_{\odot })<10$) shows 35-50% environmental contribution compared to just 8-30% for massive centrals, while satellite galaxies experience consistently stronger environmental effects than centrals across all populations. Furthermore, we find that the most significant attribute from neighboring subhalos for predicting target galaxy properties is its distance to the nearest neighboring galaxy. These quantitative results offer guidance for constructing more sophisticated empirical and semi-analytic models of galaxy formation that explicitly include environmental dependence as a function of galaxy type and mass.

accepted to MNRAS

References in corpus (25)

• Array Programming with NumPy
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Mass and environment as drivers of galaxy evolution in SDSS and zCOSMOS and the origin of the Schechter function
• The Herschel view of the dominant mode of galaxy growth from z=4 to the present day
• Strangulation as the primary mechanism for shutting down star formation in galaxies
• Halo assembly bias and its effects on galaxy clustering
• The CAMELS project: Cosmology and Astrophysics with MachinE Learning Simulations
• Dependence of Galaxy Quenching on Halo Mass and Distance from its Centre
• Satellite abundances around bright isolated galaxies
• Environmental Dependence of Cold Dark Matter Halo Formation
• Void Statistics in Large Galaxy Redshift Surveys: Does Halo Occupation of Field Galaxies Depend on Environment?
• On the influence of halo mass accretion history on galaxy properties and assembly bias
• Relative distribution of dark matter, gas, and stars around cosmic filaments in the IllustrisTNG simulation
• $\text{Mangrove}$: Learning Galaxy Properties from Merger Trees
• From Dark Matter to Galaxies with Convolutional Networks
• Using Galaxy Pairs to Probe Star Formation During Major Halo Mergers
• The Physical Origin of Galactic Conformity: From Theory to Observation
• On the environmental influence of groups and clusters of galaxies beyond the virial radius: Galactic conformity at few Mpc scales
• The SAGA Survey. V. Modeling Satellite Systems around Milky Way-mass Galaxies with Updated UniverseMachine
• Identification, mass and age of primary red clump stars from spectral features derived with the LAMOST DR7
• Star Formation Histories from SEDs and CMDs Agree: Evidence for Synchronized Star Formation in Local Volume Dwarf Galaxies over the Past 3 Gyr
• How the Galaxy-Halo Connection Depends on Large-Scale Environment
• The Beyond-Halo Mass Effects of the Cosmic Web Environment on Galaxies
• A Study on the Baryon Acoustic Oscillation with Topological Data Analysis
• Searching for Conformity Across Cosmic Time with Local Group and Local Volume Star Formation Histories