Galaxy cluster mass accretion rates from IllustrisTNG

Abstract

We use simulated cluster member galaxies from Illustris TNG300-1 to develop a technique for measuring the galaxy cluster mass accretion rate (MAR) that can be applied directly to observations. We analyze 1318 IllustrisTNG clusters of galaxies with $M_{200c}>10^{14}$M${}_{\odot }$ and $0.01\le z\le 1.04$. The MAR we derive is the ratio between the mass of a spherical shell located in the infall region and the time for the infalling shell to accrete onto the virialized region of the cluster. At fixed redshift, an $\sim 1$ order of magnitude increase in $M_{200c}$ results in a comparable increase in MAR. At fixed mass, the MAR increases by a factor of $\sim 5$ from $z=0.01$ to $z=1.04$. The MAR estimates derived from the caustic technique are unbiased and lie within 20% of the MARs based on the true mass profiles. This agreement is crucial for observational derivation of the MAR. The IllustrisTNG results are also consistent with (i) previous merger tree approaches based on N-body dark matter only simulations and with (ii) previously determined MARs of real clusters based on the caustic method. Future spectroscopic and photometric surveys will provide MARs of enormous cluster samples with mass profiles derived from both spectroscopy and weak lensing. Combined with future larger volume hydrodynamical simulations that extend to higher redshift, the MAR promises important insights into evolution of massive systems of galaxies.

14 pagers, 13 figures, 4 tables. Accepted for publication in A&A

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Cited by in corpus (5)

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• Caustic and hydrostatic mass bias: Implications for modified gravity
• Effects of Environment on the Size Evolution of Quiescent Galaxies: Comparing Galaxies in Clusters and in the Field at Two Rest-frame Wavelengths
• Differences in baryonic and dark matter scaling relations of galaxy clusters: A comparison between IllustrisTNG simulations and observations
• Predicting the Scaling Relations between the Dark Matter Halo Mass and Observables from Generalised Profiles II: Intracluster Gas Emission