Machine Learning to identify ICL and BCG in simulated galaxy clusters

Abstract

Nowadays, Machine Learning techniques offer fast and efficient solutions for classification problems that would require intensive computational resources via traditional methods. We examine the use of a supervised Random Forest to classify stars in simulated galaxy clusters after subtracting the member galaxies. These dynamically different components are interpreted as the individual properties of the stars in the Brightest Cluster Galaxy (BCG) and IntraCluster Light (ICL). We employ matched stellar catalogues (built from the different dynamical properties of BCG and ICL) of 29 simulated clusters from the DIANOGA set to train and test the classifier. The input features are cluster mass, normalized particle cluster-centric distance, and rest-frame velocity. The model is found to correctly identify most of the stars, while the larger errors are exhibited at the BCG outskirt, where the differences between the physical properties of the two components are less obvious. We investigate the robustness of the classifier to numerical resolution, redshift dependence (up to $z=1$), and included astrophysical models. We claim that our classifier provides consistent results in simulations for $z<1$, at different resolution levels and with significantly different subgrid models. The phase-space structure is examined to assess whether the general properties of the stellar components are recovered: (i) the transition radius between BCG-dominated and ICL-dominated region is identified at $0.04$ \r200; (ii) the BCG outskirt ($>0.1$ \r200) is significantly affected by uncertainties in the classification process. In conclusion, this work suggests the importance of employing Machine Learning to speed up a computationally expensive classification in simulations.

arXiv comment19 pages, accepted to MNRAS

References in corpus (36)

• A Universal Density Profile from Hierarchical Clustering
• The cosmological simulation code GADGET-2
• Populating a cluster of galaxies - I. Results at z=0
• Substructures in hydrodynamical cluster simulations
• The statistics of LCDM Halo Concentrations
• A Census of Baryons in Galaxy Clusters and Groups
• The Phase-Space Density Profiles of Cold Dark Matter Halos
• The Importance of Mergers for the Origin of Intracluster Stars in Cosmological Simulations of Galaxy Clusters
• On the nature of hydrostatic equilibrium in galaxy clusters
• CLASH-VLT: The mass, velocity-anisotropy, and pseudo-phase-space density profiles of the z=0.44 galaxy cluster MACS 1206.2-0847
• The Burrell Schmidt Deep Virgo Survey: Tidal Debris, Galaxy Halos, and Diffuse Intracluster Light in the Virgo Cluster
• The Fornax Deep Survey with VST. I. The extended and diffuse stellar halo of NGC~1399 out to 192 kpc
• The Diffuse Light in Simulations of Galaxy Clusters
• Dynamical insight into dark-matter haloes
• Intracluster stars in simulations with AGN feedback
• Intracluster light and the extended stellar envelopes of cD galaxies: An analytical description
• Intracluster light: a luminous tracer for dark matter in clusters of galaxies
• Intracluster Light at the Frontier II: The Frontier Fields Clusters
• Dark Energy Survey Year 1 results: Detection of Intra-cluster Light at Redshift $\sim$ 0.25
• Formation and Incidence of Shell Galaxies in the Illustris Simulation
• The Cluster Velocity Dispersion of the Abell 2199 cD Halo of NGC 6166
• Structure of Brightest Cluster Galaxies and Intracluster Light
• Dynamical difference between the cD galaxy and the stellar diffuse component in simulated galaxy clusters
• Brightest cluster galaxies in cosmological simulations: achievements and limitations of AGN feedback models
• The Fornax Deep Survey with VST. VIII. Connecting the accretion history with the cluster density
• The intra-cluster light as a tracer of the total matter density distribution: a view from simulations
• The buildup of the intracluster light of Abell 85 as seen by Subaru's Hyper Suprime-Cam
• The DIANOGA simulations of galaxy clusters: characterizing star formation in proto-clusters
• BCG Mass Evolution in Cosmological Hydro-Simulations
• The Outer Halos of Very Massive Galaxies: BCGs and their DSC in the Magneticum Simulations
• From Stellar Halos to Intracluster Light: the physics of the Intra-Halo Stellar Component in cosmological hydrodynamical simulations
• Discovery of a Possible Splashback Feature in the Intracluster Light of MACS J1149.5+2223
• The dynamics of z~1 clusters of galaxies from the GCLASS survey
• The Transition Region between Brightest Cluster Galaxies and Intra-Cluster Light in Galaxy Groups and Clusters
• Brightest Cluster Galaxies and Intra-Cluster Light: Their Mass Distribution in the Innermost Regions of Groups and Clusters
• On the phase-space structure of galaxy clusters from cosmological simulations

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• Characterising the intra-cluster light in The Three Hundred simulations
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• Tracing the evolution of brightest galaxies and diffuse light in galaxy groups
• The origin of the intra-cluster light in The Three Hundred simulations