scholarly journals Relative distribution of dark matter and stellar mass in three massive galaxy clusters

2015 ◽  
Vol 575 ◽  
pp. A108 ◽  
Author(s):  
S. Andreon
2021 ◽  
Vol 504 (2) ◽  
pp. 1999-2013
Author(s):  
Syeda Lammim Ahad ◽  
Yannick M Bahé ◽  
Henk Hoekstra ◽  
Remco F J van der Burg ◽  
Adam Muzzin

ABSTRACT Galaxy clusters are excellent probes to study the effect of environment on galaxy formation and evolution. Along with high-quality observational data, accurate cosmological simulations are required to improve our understanding of galaxy evolution in these systems. In this work, we compare state-of-the-art observational data of massive galaxy clusters ($\gt 10^{14}\, \textrm {M}_{\odot }$) at different redshifts (0 < z < 1.5) with predictions from the Hydrangea suite of cosmological hydrodynamic simulations of 24 massive galaxy clusters ($\gt 10^{14}\, \textrm {M}_{\odot }$ at z = 0). We compare three fundamental observables of galaxy clusters: the total stellar mass-to-halo mass ratio, the stellar mass function, and the radial mass density profile of the cluster galaxies. In the first two of these, the simulations agree well with the observations, albeit with a slightly too high abundance of $M_\star \lesssim 10^{10} \, \mathrm{M}_\odot$ galaxies at z ≳ 1. The Navarro–Frenk–White concentrations of cluster galaxies increase with redshift, in contrast to the decreasing dark matter (DM) halo concentrations. This previously observed behaviour is therefore due to a qualitatively different assembly of the smooth DM halo compared to the satellite population. Quantitatively, we, however, find a discrepancy in that the simulations predict higher stellar concentrations than observed at lower redshifts (z < 0.3), by a factor of ≈2. This may be due to selection bias in the simulations, or stem from shortcomings in the build-up and stripping of their inner satellite halo.


2020 ◽  
Vol 496 (4) ◽  
pp. 4717-4733 ◽  
Author(s):  
Qiuhan He ◽  
Hongyu Li ◽  
Ran Li ◽  
Carlos S Frenk ◽  
Matthieu Schaller ◽  
...  

ABSTRACT We determine the inner density profiles of massive galaxy clusters (M200 > 5 × 1014 M⊙) in the Cluster-EAGLE (C-EAGLE) hydrodynamic simulations, and investigate whether the dark matter density profiles can be correctly estimated from a combination of mock stellar kinematical and gravitational lensing data. From fitting mock stellar kinematics and lensing data generated from the simulations, we find that the inner density slopes of both the total and the dark matter mass distributions can be inferred reasonably well. We compare the density slopes of C-EAGLE clusters with those derived by Newman et al. for seven massive galaxy clusters in the local Universe. We find that the asymptotic best-fitting inner slopes of ‘generalized’ Navarro–Frenk–White (gNFW) profiles, γgNFW, of the dark matter haloes of the C-EAGLE clusters are significantly steeper than those inferred by Newman et al. However, the mean mass-weighted dark matter density slopes of the simulated clusters are in good agreement with the Newman et al. estimates. We also find that the estimate of γgNFW is very sensitive to the constraints from weak lensing measurements in the outer parts of the cluster and a bias can lead to an underestimate of γgNFW.


2020 ◽  
Vol 494 (1) ◽  
pp. 804-818 ◽  
Author(s):  
Gurpreet Kaur Cheema ◽  
Marcin Sawicki ◽  
Liz Arcila-Osejo ◽  
Anneya Golob ◽  
Thibaud Moutard ◽  
...  

ABSTRACT We use a 27.6 deg2 survey to measure the clustering of gzKs-selected quiescent galaxies at z ∼ 1.6, focusing on ultramassive quiescent galaxies. We find that z ∼ 1.6 Ultra-Massive Passively Evolving Galaxies (UMPEGs), which have Ks(AB) < 19.75 (stellar masses of M⋆$\gtrsim10^{11.4}\,\mathrm{ M}_{\odot }$ and mean <M⋆>  = 1011.5 M⊙), cluster more strongly than any other known galaxy population at high redshift. Comparing their correlation length, r0 = 29.77 ± 2.75h−1Mpc, with the clustering of dark matter (DM) haloes in the Millennium XXL N-body simulation suggests that these z ∼ 1.6 UMPEGs reside in DM haloes of mass Mh ∼ 1014.1h−1M⊙. Such very massive z ∼ 1.6 haloes are associated with the ancestors of z ∼ 0 massive galaxy clusters such as the Virgo and Coma clusters. Given their extreme stellar masses and lack of companions with comparable mass, we surmise that these UMPEGs could be the already-quenched central massive galaxies of their (proto)clusters. We conclude that with only a modest amount of further growth in their stellar mass, z ∼ 1.6 UMPEGs could be the progenitors of some of the massive central galaxies of present-day massive galaxy clusters observed to be already very massive and quiescent near the peak epoch of the cosmic star formation.


2017 ◽  
Vol 473 (1) ◽  
pp. L69-L73 ◽  
Author(s):  
A M C Le Brun ◽  
M Arnaud ◽  
G W Pratt ◽  
R Teyssier

2021 ◽  
Vol 502 (2) ◽  
pp. 1785-1796
Author(s):  
R A Jackson ◽  
S Kaviraj ◽  
G Martin ◽  
J E G Devriendt ◽  
A Slyz ◽  
...  

ABSTRACT In the standard ΛCDM (Lambda cold dark matter) paradigm, dwarf galaxies are expected to be dark matter-rich, as baryonic feedback is thought to quickly drive gas out of their shallow potential wells and quench star formation at early epochs. Recent observations of local dwarfs with extremely low dark matter content appear to contradict this picture, potentially bringing the validity of the standard model into question. We use NewHorizon, a high-resolution cosmological simulation, to demonstrate that sustained stripping of dark matter, in tidal interactions between a massive galaxy and a dwarf satellite, naturally produces dwarfs that are dark matter-deficient, even though their initial dark matter fractions are normal. The process of dark matter stripping is responsible for the large scatter in the halo-to-stellar mass relation in the dwarf regime. The degree of stripping is driven by the closeness of the orbit of the dwarf around its massive companion and, in extreme cases, produces dwarfs with halo-to-stellar mass ratios as low as unity, consistent with the findings of recent observational studies. ∼30 per cent of dwarfs show some deviation from normal dark matter fractions due to dark matter stripping, with 10 per cent showing high levels of dark matter deficiency (Mhalo/M⋆ < 10). Given their close orbits, a significant fraction of dark matter-deficient dwarfs merge with their massive companions (e.g. ∼70 per cent merge over time-scales of ∼3.5 Gyr), with the dark matter-deficient population being constantly replenished by new interactions between dwarfs and massive companions. The creation of these galaxies is therefore a natural by-product of galaxy evolution and their existence is not in tension with the standard paradigm.


2019 ◽  
Vol 15 (S356) ◽  
pp. 226-226
Author(s):  
Viola Allevato

AbstractThe presence of a super massive BH in almost all galaxies in the Universe is an accepted paradigm in astronomy. How these BHs form and how they co-evolve with the host galaxy is one of the most intriguing unanswered problems in modern Cosmology and of extreme relevance to understand the issue of galaxy formation. Clustering measurements can powerfully test theoretical model predictions of BH triggering scenarios and put constraints on the typical environment where AGN live in, through the connection with their host dark matter halos. In this talk, I will present some recent results on the AGN clustering dependence on host galaxy properties, such as galaxy stellar mass, star formation rate and specific BH accretion rate, based on X-ray selected Chandra COSMOS Legacy Type 2 AGN. We found no significant AGN clustering dependence on galaxy stellar mass and specif BHAR for Type 2 COSMOS AGN at mean z ∼ 1.1, with a stellar - halo mass relation flatter than predicted for non active galaxies in the Mstar range probed by our sample. We also observed a negative clustering dependence on SFR, with AGN hosting halo mass increasing with decreasing SFR. Mock catalogs of active galaxies in hosting dark matter halos with logMh[Msun] > 12.5, matched to have the same X-ray luminosity, stellar mass and BHAR of COSMOS AGN predict the observed Mstar - Mh, BHAR - Mh and SFR-Mh relations, at z ∼ 1.


2001 ◽  
Vol 553 (2) ◽  
pp. 668-676 ◽  
Author(s):  
H. Ebeling ◽  
A. C. Edge ◽  
J. P. Henry

2020 ◽  
Vol 494 (4) ◽  
pp. 4706-4712 ◽  
Author(s):  
Andrew Robertson ◽  
Richard Massey ◽  
Vincent Eke

ABSTRACT We assess a claim that observed galaxy clusters with mass ${\sim}10^{14} \mathrm{\, M_\odot }$ are more centrally concentrated than predicted in lambda cold dark matter (ΛCDM). We generate mock strong gravitational lensing observations, taking the lenses from a cosmological hydrodynamical simulation, and analyse them in the same way as the real Universe. The observed and simulated lensing arcs are consistent with one another, with three main effects responsible for the previously claimed inconsistency. First, galaxy clusters containing baryonic matter have higher central densities than their counterparts simulated with only dark matter. Secondly, a sample of clusters selected because of the presence of pronounced gravitational lensing arcs preferentially finds centrally concentrated clusters with large Einstein radii. Thirdly, lensed arcs are usually straighter than critical curves, and the chosen image analysis method (fitting circles through the arcs) overestimates the Einstein radii. After accounting for these three effects, ΛCDM predicts that galaxy clusters should produce giant lensing arcs that match those in the observed Universe.


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