Central matter distributions in rich clusters of galaxies   from 
${z\sim{0}}$ 
to ${z\sim {0.5}}$

Adami, C.; Mazure, A.; Ulmer, M. P.; Savine, C.

doi:10.1051/0004-6361:20010344

Cited by 13 publications

(15 citation statements)

References 16 publications

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“…In the case of a cusped model, the best fit values are β = 0.49 ± 0.10 and r c = 3.4 ± 0.3 arcmin (0.72 ± 0.07 Mpc). The values of β are, within the errors, in agreement with those found by Adami et al (2001) from a sample of nearby clusters (β beta model = 1.0 ± 0.02 and β cusped = 0.56 ± 0.01), while the values of r c are significantly higher (the values in Adami et al 2001, when converted to our cosmology, are r c = 0.13 ± 0.07 Mpc for the beta model and r c = 0.45 ± 0.05 Mpc for the cusped model). For comparison, the values for the gas profile are r c = 1.2 arcmin and β = 0.62 (Elbaz et al 1995).…”

Section: Density Profilessupporting

confidence: 89%

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A 2163: Merger events in the hottest Abell galaxy cluster

Maurogordato¹,

Cappi

Ferrari

et al. 2008

A&A

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Context. A 2163 is among the richest and most distant Abell clusters, presenting outstanding properties in different wavelength domains. X-ray observations have revealed a distorted gas morphology and strong features have been detected in the temperature map, suggesting that merging processes are important in this cluster. However, the merging scenario is not yet well-defined. Aims. We have undertaken a complementary optical analysis, aiming to understand the dynamics of the system, to constrain the merging scenario and to test its effect on the properties of galaxies. Methods. We present a detailed optical analysis of A 2163 based on new multicolor wide-field imaging and medium-to-high resolution spectroscopy of several hundred galaxies. Results. The projected galaxy density distribution shows strong subclustering with two dominant structures: a main central component (A), and a northern component (B), visible both in optical and in X-ray, with two other substructures detected at high significance in the optical. At magnitudes fainter than R = 19, the galaxy distribution shows a clear elongation approximately with the east-west axis extending over 4 h −1 70 Mpc, while a nearly perpendicular bridge of galaxies along the north-south axis appears to connect (B) to (A). The (A) component shows a bimodal morphology, and the positions of its two density peaks depend on galaxy luminosity: at magnitudes fainter than R = 19, the axis joining the peaks shows a counterclockwise rotation (from NE/SW to E-W) centered on the position of the X-ray maximum. Our final spectroscopic catalog of 512 objects includes 476 new galaxy redshifts. We have identified 361 galaxies as cluster members; among them, 326 have high precision redshift measurements, which allow us to perform a detailed dynamical analysis of unprecedented accuracy. The cluster mean redshift and velocity dispersion are respectively z = 0.2005 ± 0.0003 and 1434 ± 60 km s −1 . We spectroscopically confirm that the northern and western components (A 2163-B and A 2163-C) belong to the A 2163 complex. The velocity distribution shows multi-modality, with an overall bimodal structure peaking at ∼59 200 km s −1 and ∼60 500 km s −1 . A significant velocity gradient (∼1250 km s −1 ) is detected along the NE/SW axis of the cluster, which partially explains the detected bimodality. A 2163 appears to be exceptionally massive: the cluster virial mass is M vir = 3.8± 0.4× 10 15 M h −1 70 . Conclusions. Our analysis of the optical data, combined with the available information from X-ray observations and predictions of numerical simulations, supports a scenario in which A 2163-A has undergone a recent (t ∼ 0.5 Gyr) merger along a NE/SW (or E-W) axis, and A 2163-B is connected to the main complex, and is probably infalling on A 2163-A.

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Section: Density Profilessupporting

confidence: 89%

“…2 )) β , as defined in Adami et al (2001), using a Levenverg-Marquardt χ 2 algorithm, which gives simultaneously the three parameters σ 0 , r c and β.…”

Section: Density Profilesmentioning

confidence: 99%

A 2163: Merger events in the hottest Abell galaxy cluster

Maurogordato¹,

Cappi

Ferrari

et al. 2008

A&A

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“…The profile of the low-mass objects displays a core, and is less centrally concentrated than that of the high-mass clusters which is in fact rather cuspy. As expected, due to the presence of the Brightest Cluster Galaxies at the center of the systems, the luminosity profiles are generally more cuspy than the density profiles in the same cluster mass bins (Adami et al 2001).…”

Section: Number Density Profiles and Projection Effectssupporting

confidence: 74%

RASS-SDSS galaxy cluster survey

Popesso¹,

Biviano

Böhringer

et al. 2006

A&A

135

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Aims. We explore the mass-to-light ratio in galaxy clusters and its relation to the cluster mass. Methods. We study the relations among the optical luminosity (L op ), the cluster mass (M 200 ) and the number of cluster galaxies within r 200 (N gal ) in a sample of 217 galaxy clusters with confirmed 3D overdensity. We correct for projection effect, by determining the galaxy surface number density profile in our cluster sample. This is best fitted by a cored King profile in low and intermediate mass systems. The core radius decreases with cluster mass, and, for the highest mass clusters, the profile is better represented by a generalized King profile or a cuspy Navarro, Frenk & White profile. Results. We find a very tight proportionality between L op and N gal , which, in turn, links the cluster mass-to-light ratio to the Halo Occupation Distribution N gal vs. M 200 . After correcting for projection effects, the slope of the L op −M 200 and N gal −M 200 relations is found to be 0.92 ± 0.03, close, but still significantly less than unity. We show that the non-linearity of these relations cannot be explained by variations of the galaxy luminosity distributions and of the galaxy M/L with the cluster mass. Conclusions. We suggest that the nonlinear relation between number of galaxies and cluster mass reflects an underlying nonlinear relation between number of subhaloes and halo mass.

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“…We adopt their average value of r s = 0.26 Mpc among the 41 clusters whose velocity dispersions are observationally determined. The recent work based on a sample of 77 composite ENACS clusters gives the similar result, r s = 0.318 Mpc (Adami et al 2001).…”

Section: Samplesupporting

confidence: 62%

Observational tests of the $\delta_{\mathsf{c}}{-}$ $\vec M$ $_{\mathsf{vir}}$ relation in hierarchical clustering models

Cheng

2001

A&A

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Abstract. Observational determinations of the correlation between the characteristic density δc and the virial mass Mvir of dark halos constitute a critical test for models of hierarchical structure formation. Using the dynamical properties of dark halos reconstructed from the galaxy distributions in massive systems (groups/clusters) and the rotation curves in less massive systems (dwarf, low surface brightness and spiral galaxies) drawn from the literature, we confirm the existence of the δc-Mvir relation over a broad mass range from 10 10 M to 10 15 M , which is in gross consistency with the prediction of a flat cosmological model with ΩM = 0.3 and ΩΛ = 0.7. It is pointed out that previous analyses based on the measurements of X-ray emitting gas and the hydrostatic equilibrium hypothesis, which claimed a shallower scale-free spectrum of n ≈ −1 for initial density fluctuations, may suffer from nongravitational heating influence especially in low-mass systems.

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Central matter distributions in rich clusters of galaxies from ${z\sim{0}}$ to ${z\sim {0.5}}$

Cited by 13 publications

References 16 publications

A 2163: Merger events in the hottest Abell galaxy cluster

A 2163: Merger events in the hottest Abell galaxy cluster

RASS-SDSS galaxy cluster survey

Observational tests of the $\delta_{\mathsf{c}}{-}$ $\vec M$ $_{\mathsf{vir}}$ relation in hierarchical clustering models

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