Browsing by Author "Cui, Weiguang"
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Item Boundless baryons: how diffuse gas contributes to anisotropic tSZ signal around simulated three hundred clusters(Oxford University Press, 2023) Davé, Romeel; Lokken, Martine; Cui, WeiguangUpcoming advances in galaxy surveys and cosmic microwave background data will enable measurements of the anisotropic distribution of diffuse gas in filaments and superclusters at redshift z = 1 and beyond, observed through the thermal Sunyaev–Zel’dovich (tSZ) effect. These measurements will help distinguish between different astrophysical feedback models, account for baryons that appear to be ‘missing’ from the cosmic census, and present opportunities for using locally anisotropic tSZ statistics as cosmological probes. This study seeks to guide such future measurements by analysing whether diffuse intergalactic gas is a major contributor to anisotropic tSZ signal in THE THREE HUNDRED GIZMO-SIMBA hydrodynamic simulations. We apply multiple different halo boundary and temperature criteria to divide concentrated from diffuse gas at z = 1, then create mock Compton- y maps for the separated components. The maps from 98 simulation snapshots are centred on massive galaxy clusters, oriented by the most prominent filament axis in the galaxy distribution, and stacked. Results vary significantly depending on the definition used for diffuse gas, indicating that assumptions should be clearly defined when claiming observations of the warm-hot intergalactic medium. In all cases, the diffuse gas is important, contributing 25–60 per cent of the tSZ signal in the far field (>4 h−1 comoving Mpc) from the stacked clusters. The gas 1–2 virial radii from halo centres is especially key. Oriented stacking and environmental selections help to amplify the signal from the warm-hot intergalactic medium, which is aligned but less concentrated along the filament axis than the hot halo gas.Item nIFTy galaxy cluster simulations – V. Investigation of the cluster infall region(Oxford University Press, 2016) Arthur, Jake; Pearce, Frazer R.; Gray, Meghan E.; Elahi, Pascal J.; Knebe, Alexander; Beck, Alexander M.; Cui, Weiguang; Cunnama, Daniel; Dave, RomeelWe examine the properties of the galaxies and dark matter haloes residing in the cluster infall region surrounding the simulated cold dark matter galaxy cluster studied by Elahi et al. at z = 0. The 1.1 × 1015 h−1M galaxy cluster has been simulated with eight different hydrodynamical codes containing a variety of hydrodynamic solvers and sub-grid schemes. All models completed a dark-matter-only, non-radiative and full-physics run from the same initial conditions. The simulations contain dark matter and gas with mass resolution mDM = 9.01 × 108 h−1M and mgas = 1.9 × 108 h−1M , respectively. We find that the synthetic cluster is surrounded by clear filamentary structures that contain ∼60 per cent of haloes in the infall region with mass ∼1012.5–1014 h−1M , including 2–3 group-sized haloes (>1013 h−1M ). However, we find that only ∼10 per cent of objects in the infall region are sub-haloes residing in haloes, which may suggest that there is not much ongoing pre-processing occurring in the infall region at z = 0. By examining the baryonic content contained within the haloes, we also show that the code-to-code scatter in stellar fraction across all halo masses is typically ∼2 orders of magnitude between the two most extreme cases, and this is predominantly due to the differences in sub-grid schemes and calibration procedures that each model uses. Models that do not include active galactic nucleus feedback typically produce too high stellar fractions compared to observations by at least ∼1 order of magnitude.Item The three hundred project: The stellar and gas profiles(Oxford University Press, 2020) Dave, Romeel; Li, Qingyang; Cui, WeiguangUsing the catalogues of galaxy clusters from The Three Hundred project, modelled with both hydrodynamic simulations (GADGET-X and GADGET-MUSIC), and semi-analytical models (SAMs), we study the scatter and self-similarity of the profiles and distributions of the baryonic components of the clusters: the stellar and gas mass, metallicity, the stellar age, gas temperature, and the (specific) star formation rate. Through comparisons with observational results, we find that the shape and the scatter of the gas density profiles matches well the observed trends including the reduced scatter at large radii which is a signature of self-similarity suggested in previous studies. One of our simulated sets, GADGET-X, reproduces well the shape of the observed temperature profile, while GADGET-MUSIC has a higher and flatter profile in the cluster centre and a lower and steeper profile at large radii. The gas metallicity profiles from both simulation sets, despite following the observed trend, have a relatively lower normalization.