The growth of brightest cluster galaxies in the TNG300 simulation:dissecting the contributions from mergers and in situ star formation

Abstract

We investigate the formation of brightest cluster galaxies (BCGs) in the TNG300 cosmological simulation of the IllustrisTNG project. Our cluster sample consists of 700 haloes with $M_{200}\ge 5\times 10^{13}{\mathrm{M}}_{\odot }$ at $z=0$, along with their progenitors at earlier epochs. This includes 280 systems with $M_{200}\ge 10^{14}{\mathrm{M}}_{\odot }$ at $z=0$, as well as three haloes with $M_{200}\ge 10^{15}{\mathrm{M}}_{\odot }$. We find that the stellar masses and star formation rates of our simulated BCGs are in good agreement with observations at $z\lesssim 0.4$, and that they have experienced, on average, $\sim$2 ($\sim$3) major mergers since $z=1$ ($z=2$). Separating the BCG from the intracluster light (ICL) by means of a fixed 30 kpc aperture, we find that the fraction of stellar mass contributed by ex situ (i.e. accreted) stars at $z=0$ is approximately 70, 80, and 90 per cent for the BCG, BCG+ICL, and ICL, respectively. Tracking our simulated BCGs back in time using the merger trees, we find that they became dominated by ex situ stars at $z\sim$1-2, and that half of the stars that are part of the BCG at $z=0$ formed early ($z\sim 3$) in other galaxies, but `assembled' onto the BCG until later times ($z\approx 0.8$ for the whole sample, $z\approx 0.5$ for BCGs in $M_{200}\ge 5\times 10^{14}{\mathrm{M}}_{\odot }$ haloes). Finally, we show that the stellar mass profiles of BCGs are often dominated by ex situ stars at all radii, with stars from major mergers being found closer to the centre, while stars that were tidally stripped from other galaxies dominate the outer regions.

19 pages, 11 figures. Accepted for publication in MNRAS

References in corpus (32)

• Cosmic Star Formation History
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• The hierarchical formation of the brightest cluster galaxies
• Properties of galaxies reproduced by a hydrodynamic simulation
• Simulating galaxy formation with black hole driven thermal and kinetic feedback
• Introducing the Illustris Project: the evolution of galaxy populations across cosmic time
• How special are Brightest Group and Cluster Galaxies?
• On the prevalence of radio-loud AGN in brightest cluster galaxies: implications for AGN heating of cooling flows
• The Size Evolution of Star-forming and Quenched Galaxies in the IllustrisTNG simulation
• The Importance of Mergers for the Origin of Intracluster Stars in Cosmological Simulations of Galaxy Clusters
• The role of mergers and halo spin in shaping galaxy morphology
• Ejective and preventative: the IllustrisTNG black hole feedback and its effects on the thermodynamics of the gas within and around galaxies
• A chronicle of galaxy mass assembly in the EAGLE simulation
• Building Late-Type Spiral Galaxies by In-Situ and Ex-Situ Star Formation
• Quenched fractions in the IllustrisTNG simulations: the roles of AGN feedback, environment, and pre-processing
• Quenched fractions in the IllustrisTNG simulations: comparison with observations and other theoretical models
• Brightest Cluster Galaxies at the Present Epoch
• Intracluster Light at the Frontier II: The Frontier Fields Clusters
• Lost but not Forgotten: Intracluster Light in Galaxy Groups and Clusters
• Spatially Resolved Star Formation and Inside-out Quenching in the TNG50 Simulation and 3D-HST Observations
• Intra Cluster Light properties in the CLASH-VLT cluster MACS J1206.2-0847
• The intra-cluster light as a tracer of the total matter density distribution: a view from simulations
• The DIANOGA simulations of galaxy clusters: characterizing star formation in proto-clusters
• Photometric dissection of Intracluster Light and its correlations with host cluster properties
• The Growth of Brightest Cluster Galaxies and Intracluster Light Over the Past Ten Billion Years
• The stellar halos of ETGs in the IllustrisTNG simulations: II. Accretion, merger history, and dark halo connection
• The Rarity of Star Formation in Brightest Cluster Galaxies as Measured by WISE
• Radio AGN in 13,240 galaxy clusters from the Sloan Digital Sky Survey
• Stellar and Weak Lensing Profiles of Massive Galaxies in the Hyper-Suprime Cam Survey and in Hydrodynamic Simulations
• Sunyaev-Zel'dovich effect and X-ray scaling relations of galaxies, groups and clusters in the IllustrisTNG simulations
• The Evolution of Brightest Cluster Galaxies in the Nearby Universe II: The star-formation activity and the Stellar Mass from Spectral Energy Distribution

Cited by in corpus (21)

• Galaxy Mergers in the Epoch of Reionization I: A JWST Study of Pair Fractions, Merger Rates, and Stellar Mass Accretion Rates at $z=4.5-11.5$
• Cosmic Vine: A z=3.44 large-scale structure hosting massive quiescent galaxies
• Characterising the intra-cluster light in The Three Hundred simulations
• Dianoga SIDM: galaxy cluster self-interacting dark matter simulations
• Minor Mergers are not enough: The importance of Major Mergers during Brightest Cluster Galaxy assembly
• Assembly of the Intracluster Light in the Horizon-AGN Simulation
• NOEMA formIng Cluster survEy (NICE): Characterizing eight massive galaxy groups at $1.5<z<4$ in the COSMOS field
• The impact of assembly history on the X-ray detectability of halos. From galaxy groups to galaxy clusters
• Intra-Cluster Light as a Dynamical Clock for Galaxy Clusters: Insights from the MAGNETICUM, IllustrisTNG, Hydrangea and Horizon-AGN Simulations
• Revealing the hidden cosmic feast: A z=4.3 galaxy group hosting two optically dark, efficiently star-forming galaxies
• Growth of Ex-situ Diffuse Intragroup Light in Simulated Galaxy Groups
• Memoirs of mass accretion: probing the edges of intracluster light in simulated galaxy clusters
• Cosmic Vine: High abundance of massive galaxies and dark matter halos in a forming cluster at z=3.44
• On the Origin of Intracluster Light based on the High-resolution Simulation, NewCluster
• The Outskirt Stellar Mass of Low-Redshift Massive Galaxies is an Excellent Halo Mass Proxy in Illustris/IllustrisTNG Simulations
• Selecting Clusters and Protoclusters via Stellar Mass Density: I. Method and tests on Mock HSC-SSP catalogs
• Euclid: A blue galaxy population and a brightest cluster galaxy in the making in a $z\sim 1.74$ MaDCoWS2 galaxy cluster candidate
• The origin of the intra-cluster light in The Three Hundred simulations
• The History of Galaxy Mergers in IllustrisTNG
• Stellar halos of bright central galaxies II: Scaling relations, colors and metallicity evolution with redshift
• Tracing the evolution of brightest galaxies and diffuse light in galaxy groups