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 $10^{14} < {\rm M}_{\rm 500c} / M_\odot < 2 \times 10^{15}$ at $z=0$. We focus on the proposed classification of clusters into cool-core (CC) and non-cool-core (NCC) populations, the $z=0$ 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 $z=0$ and based on central cooling time, the strong CC fraction is $f_{\rm SCC} = 24\%$, compared to $f_{\rm WCC} = 60\%$ and $f_{\rm NCC} = 16\%$ 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 $z=0$ to $z=2$ 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 $z=0$. 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 $< 10\%$ 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

Chemical abundances in the outskirts of nearby galaxy groups measured with joint Suzaku and Chandra observations

We report results from deep Suzaku and mostly snapshot Chandra observations of four nearby galaxy groups: MKW4, Antlia, RXJ1159+5531, and ESO3060170. Their peak temperatures vary over 2-3 keV, making them the smallest systems with gas properties constrained to their viral radii. The average Fe abundance in the outskirts (R $>$ 0.25R$_{200}$) of their intragroup medium (IGrM) is $Z_{\rm Fe}=0.309\pm0.018$ $Z_\odot$ with $\chi^2$ = 14 for 12 degrees of freedom, which is remarkably uniform and strikingly similar to that of massive galaxy clusters, and is fully consistent with the numerical predictions from the IllustrisTNG cosmological simulation. Our results support an early-enrichment scenario among galactic systems over an order of magnitude in mass, even before their formation. When integrated out to R$_{200}$, we start to see a tension between the measured Fe content in ICM and what is expected from supernovae yields. We further constrain their O, Mg, Si, S, and Ni abundances. The abundance ratios of those elements relative to Fe are consistent with the predictions (if available) from IllustrisTNG. Their Type Ia supernovae fraction varies between 14%-21%. A pure core collapsed supernovae enrichment at group outskirts can be ruled out. Their cumulative iron-mass-to-light ratios within R$_{200}$ are half that of the Perseus cluster, which may imply that galaxy groups do not retain all of their enriched gas due to their shallower gravitational potential wells, or that groups and clusters may have different star formation histories.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Societ

Mass-Metallicity Relation from Cosmological Hydrodynamical Simulations and X-ray Observations of Galaxy Groups and Clusters

Recent X-ray observations of galaxy clusters show that the distribution of intra-cluster medium (ICM) metallicity is remarkably uniform in space and in time. In this paper, we analyse a large sample of simulated objects, from poor groups to rich clusters, to study the dependence of the metallicity and related quantities on the scale of systems. The simulations are performed with an improved version of the Smoothed-Particle-Hydrodynamics \texttt{GADGET-3} code and consider various astrophysical processes including radiative cooling, metal enrichment and feedback from stars and active galactic nuclei (AGN). The scaling between the metallicity and the temperature and its evolution obtained in the simulations agrees well with the observational results obtained from two data samples characterised by a wide range of masses and a large redshift coverage. We find that at present time ($z=0$) the iron abundance in the cluster core ($r<0.1R_{500}$) does not correlate with the temperature and does not present a significant evolution. The scale invariance is confirmed when the metallicity is related directly with the total mass. The slope of the best-fitting relations is shallow ($\beta\sim-0.1$) in the innermost regions ($r<0.5R_{500}$) and consistent with zero outside. We investigate the impact of the AGN feedback and find that it plays a key role in producing a constant value of the outskirts metallicity from groups to clusters. This finding additionally supports the picture of early enrichment

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

GC-MS analysis and cytotoxic activity of the n-hexane fraction from Curcuma sahuynhensis Škornick. & N.S.Lý leaves collected in Vietnam

Curcuma sahuynhensis Škornick. &amp; N.S.Lý is an endemic plant in Vietnam that has been used by the Sa Huynh people as a spice and medicine to cure illnesses linked to digestive disorders. Very little information is available so far about the chemical composition and biological effects of C. sahuynhensis. To find new pharmaceutical ingredients, the in vitro cytotoxic effect and the chemical profile of C. sahuynhensis leaf extract were investigated. In this study, the percolation method and liquid-liquid dispersion technique were used to extract dry sample powder. The chemical composition was detected by gas chromatography-mass spectrometry (GC-MS). The Sulforhodamine B and MTT methods were used to determine the cytotoxic activity. The chemical composition analysis showed that the leaf extract contained 14 components. The major components in the n-hexane extract were 6,10,14-trimethylpentadecan-2-one, phytol, 1-ethylbutyl hydroperoxide, isoborneol, 1-methylpentyl hydroperoxide, and neophytadiene. On human cancer cell lines, namely MFC-7, SK-LU-1, Hela, MKN-7, and HL-60, the leaf extract showed dose-dependent cytotoxic activity, with IC50 values ranging from 221.70±10.24 to 369.42±10.60 ?g/mL. The present study provides significant information on the chemical components and cytotoxic effects of the n-hexane extract from C. sahuynhensis leaves. The findings will continue to be crucial in future research on the evaluation of secondary metabolite compound analysis for cancer therapeutic effects

Students’ Perceptions on Blended Synchronous Learning in the Postcrisis Era

With the severe impacts of the Covid-19 pandemic, the educational systems have to be reformed and evolved. Blended synchronous learning has become an attractive tendency in education worldwide as the technology has mushroomed recently and attracts a vast number of users and researchers. Therefore, the current study was conducted to investigate students’ overall perceptions of blended synchronous learning as well as its benefits and challenges. 163 participants in the study have experienced ENT courses in a blended synchronous learning environment for 105 hours within 7 weeks. The instrument employed in the quantitative phase was 27 items adapted from studies by Rahman et al. (2015), López-Pérez et al. (2011), and Wu et al. (2010). Additionally, semi-structured interviews were used to have a deeper understanding of the research issues. Results indicate that more than half of participants had good perceptions about the blended synchronous learning environment and perceived various benefits as well as challenges of it. Moreover, these findings are supplemented with illustrative quotes from interview transcripts to compare and contrast with previous findings reported in the literature, and therefore this study contributes to the field by offering the learners\u27 voices

A nitrogen-doped carbon-coated silicon carbide as a robust and highly efficient metal-free catalyst for sour gas desulfurization in the presence of aromatics as contaminants

A mesoporous N-doped carbon coating for SiC extrudates shows excellent H2S desulfurization performance along with remarkably high resistance towards deactivation/fouling in the presence of aromatics as contaminant