4 research outputs found
The heart of galaxy clusters: demographics and physical properties of cool-core and non-cool-core halos in the TNG-Cluster simulation
We analyze the physical properties of the gaseous intracluster medium (ICM)
at the center of massive galaxy clusters with TNG-Cluster, a new cosmological
magnetohydrodynamical simulation. Our sample contains 352 simulated clusters
spanning a halo mass range of at . We focus on the proposed classification of clusters
into cool-core (CC) and non-cool-core (NCC) populations, the distribution
of cluster central ICM properties, and the redshift evolution of the CC cluster
population. We analyze resolved structure and radial profiles of entropy,
temperature, electron number density, and pressure. To distinguish between CC
and NCC clusters, we consider several criteria: central cooling time, central
entropy, central density, X-ray concentration parameter, and density profile
slope. According to TNG-Cluster and with no a-priori cluster selection, the
distributions of these properties are unimodal, whereby CCs and NCCs represent
the two extremes. Across the entire TNG-Cluster sample at and based on
central cooling time, the strong CC fraction is , compared
to and for weak and non-cool-cores,
respectively. However, the fraction of CCs depends strongly on both halo mass
and redshift, although the magnitude and even direction of the trends vary with
definition. The abundant statistics of simulated high-mass clusters in
TNG-Cluster enables us to match observational samples and make a comparison
with data. The CC fractions from to are in broad agreement with
observations, as are radial profiles of thermodynamical quantities, globally as
well as split for CC versus NCC halos. TNG-Cluster can therefore be used as a
laboratory to study the evolution and transformations of cluster cores due to
mergers, AGN feedback, and other physical processes.Comment: Submitted to A&A, comments welcome. See the TNG-Cluster website at
www.tng-project.org/cluster/ for more detail
X-ray inferred kinematics of the core ICM in Perseus-like clusters: insights from the TNG-Cluster simulation
The intracluster medium (ICM) of galaxy clusters encodes the impact of the
physical processes that shape these massive halos, including feedback from
central supermassive black holes (SMBHs). In this study we examine the gas
thermodynamics, kinematics, and the effects of SMBH feedback on the core of
Perseus-like galaxy clusters with a new simulation suite: TNG-Cluster. We first
make a selection of simulated clusters similar to Perseus based on total mass
and inner ICM properties, i.e. cool-core nature. We identify 30 Perseus-like
systems among the 352 TNG-Cluster halos at . Many exhibit thermodynamical
profiles and X-ray morphologies with disturbed features such as ripples,
bubbles and shock fronts that are qualitatively similar to X-ray observations
of Perseus. To study observable gas motions, we generate XRISM mock X-ray
observations and conduct a spectral analysis of the synthetic data. In
agreement with existing Hitomi measurements, TNG-Cluster predicts subsonic gas
turbulence in the central regions of Perseus-like clusters, with a typical
line-of-sight velocity dispersion of 200 km/s. This implies that turbulent
pressure contributes to the dominant thermal pressure. In TNG-Cluster,
such low (inferred) values of ICM velocity dispersion coexist with
high-velocity outflows and bulk motions of relatively small amounts of
super-virial hot gas, moving up to thousands of km/s. However, detecting these
outflows observationally may prove challenging due to their anisotropic nature
and projection effects. Driven by SMBH feedback, such outflows are responsible
for many morphological disturbances in the X-ray maps of cluster cores. They
also increase both the inferred, and intrinsic, ICM velocity dispersion. This
effect is somewhat stronger when velocity dispersion is measured from
higher-energy lines.Comment: 14 pages, 8 figures. Submitted to A&A, comments welcome. See the
TNG-Cluster website at www.tng-project.org/cluster
Introducing the TNG-Cluster Simulation: overview and physical properties of the gaseous intracluster medium
We introduce the new TNG-Cluster project, an addition to the IllustrisTNG
suite of cosmological magnetohydrodynamical simulations of galaxy formation.
Our objective is to significantly increase the statistical sampling of the most
massive and rare objects in the Universe: galaxy clusters with log(M_200c /
Msun) > 14.3 - 15.4 at z=0. To do so, we re-simulate 352 cluster regions drawn
from a 1 Gpc volume, thirty-six times larger than TNG300, keeping entirely
fixed the IllustrisTNG physical model as well as the numerical resolution. This
new sample of hundreds of massive galaxy clusters enables studies of the
assembly of high-mass ellipticals and their supermassive black holes (SMBHs),
brightest cluster galaxies (BCGs), satellite galaxy evolution and environmental
processes, jellyfish galaxies, intracluster medium (ICM) properties, cooling
and active galactic nuclei (AGN) feedback, mergers and relaxedness, magnetic
field amplification, chemical enrichment, and the galaxy-halo connection at the
high-mass end, with observables from the optical to radio synchrotron and the
Sunyaev-Zeldovich (SZ) effect, to X-ray emission, as well as their cosmological
applications. We present an overview of the simulation, the cluster sample,
selected comparisons to data, and a first look at the diversity and physical
properties of our simulated clusters and their hot ICM.Comment: Submitted to A&A. See companion papers today (Ayromlou, Lee, Lehle,
Rohr, Truong). Additional information and visuals are available on the
TNG-Cluster website at https://www.tng-project.org/cluster
An Atlas of Gas Motions in the TNG-Cluster Simulation: from Cluster Cores to the Outskirts
Galaxy clusters are unique laboratories for studying astrophysical processes
and their impact on gas kinematics. Despite their importance, the full
complexity of gas motion within and around clusters remains poorly known. This
paper is part of a series presenting first results from the new TNG-Cluster
simulation, a suite of 352 massive clusters including the full cosmological
context, mergers, accretion, baryonic processes, feedback, and magnetic fields.
Studying the dynamics and coherence of gas flows, we find that gas motions in
cluster cores and intermediate regions are largely balanced between inflows and
outflows, exhibiting a Gaussian distribution centered at zero velocity. In the
outskirts, even the net velocity distribution becomes asymmetric, featuring a
double peak where the second peak reflects cosmic accretion. Across all cluster
regions, the resulting net flow distribution reveals complex gas dynamics.
These are strongly correlated with halo properties: at a given total cluster
mass, unrelaxed, late-forming halos with less massive black holes and lower
accretion rates exhibit a more dynamic behavior. Our analysis shows no clear
relationship between line-of-sight and radial gas velocities, suggesting that
line-of-sight velocity alone is insufficient to distinguish between inflowing
and outflowing gas. Additional properties, such as temperature, can help break
this degeneracy. A velocity structure function (VSF) analysis indicates more
coherent gas motion in the outskirts and more disturbed kinematics towards halo
centers. In all cluster regions, the VSF shows a slope close to the theoretical
models of Kolmogorov (1/3), except within 50 kpc of the cluster cores, where
the slope is significantly steeper. The outcome of TNG-Cluster broadly aligns
with observations of the VSF of multiphase gas across different scales in
galaxy clusters, ranging from 1 kpc to Megaparsec scales.Comment: Submitted to A&A. See the TNG-Cluster website at
https://www.tng-project.org/cluster