scholarly journals The Three Hundred Project: The evolution of galaxy cluster density profiles

2018 ◽  
Vol 483 (3) ◽  
pp. 3390-3403 ◽  
Author(s):  
Robert Mostoghiu ◽  
Alexander Knebe ◽  
Weiguang Cui ◽  
Frazer R Pearce ◽  
Gustavo Yepes ◽  
...  
Keyword(s):  
Galaxy Cluster ◽  
Density Profiles ◽  
Cluster Density

scholarly journals An analysis of galaxy cluster mis-centring using cosmological hydrodynamic simulations

2020 ◽  
Vol 493 (1) ◽  
pp. 1120-1129
Author(s):  
Z Yan ◽  
N Raza ◽  
L Van Waerbeke ◽  
A J Mead ◽  
I G McCarthy ◽  
...  
Keyword(s):  
Galaxy Cluster ◽  
Mass Range ◽  
Three Dimensions ◽  
Cumulative Distribution ◽  
Density Profiles ◽  
Hydrodynamic Simulations ◽  
The Galaxy ◽  
Cluster Density ◽  
Cluster Properties ◽  
Using Data

ABSTRACT The location of a galaxy cluster’s centroid is typically derived from observations of the galactic and/or gas component of the cluster, but these typically deviate from the true centre. This can produce bias when observations are combined to study average cluster properties. Using data from the BAryons and HAloes of MAssive Systems (BAHAMAS) cosmological hydrodynamic simulations, we study this bias in both two and three dimensions for 2000 clusters over the 1013–1015 M⊙ mass range. We quantify and model the offset distributions between observationally motivated centres and the ‘true’ centre of the cluster, which is taken to be the most gravitationally bound particle measured in the simulation. We fit the cumulative distribution function of offsets with an exponential distribution and a Gamma distribution fit well with most of the centroid definitions. The galaxy-based centres can be seen to be divided into a mis-centred group and a well-centred group, with the well-centred group making up about $60{{\ \rm per\ cent}}$ of all the clusters. Gas-based centres are overall less scattered than galaxy-based centres. We also find a cluster-mass dependence of the offset distribution of gas-based centres, with generally larger offsets for smaller mass clusters. We then measure cluster density profiles centred at each choice of the centres and fit them with empirical models. Stacked, mis-centred density profiles fit to the Navarro–Frenk–White dark matter profile and Komatsu–Seljak gas profile show that recovered shape and size parameters can significantly deviate from the true values. For the galaxy-based centres, this can lead to cluster masses being underestimated by up to $10{{\ \rm per\ cent}}$.

scholarly journals Cross-correlation Weak Lensing of SDSS galaxy Clusters II: Cluster Density Profiles and the Mass--Richness Relation

2007 ◽  
Author(s):  
David E. Johnston ◽  
Erin S. Sheldon ◽  
Risa H. Wechsler ◽  
Eduardo Rozo ◽  
Benjamin P. Koester ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Cross Correlation ◽  
Weak Lensing ◽  
Density Profiles ◽  
Cluster Density

scholarly journals Runaway merger shocks in galaxy cluster outskirts and radio relics

2019 ◽  
Vol 488 (4) ◽  
pp. 5259-5266 ◽  
Author(s):  
Congyao Zhang ◽  
Eugene Churazov ◽  
William R Forman ◽  
Natalia Lyskova
Keyword(s):  
Galaxy Cluster ◽  
Habitable Zone ◽  
Initial State ◽  
Density Profiles ◽  
Narrow Region ◽  
Main Cluster ◽  
Uniform Medium ◽  
Strong Compression ◽  
Relativistic Particles ◽  
Massive Cluster

ABSTRACT Moderately strong shocks arise naturally when two subclusters merge. For instance, when a smaller subcluster falls into the gravitational potential of a more massive cluster, a bow shock is formed and moves together with the subcluster. After pericentre passage, however, the subcluster is decelerated by the gravity of the main cluster, while the shock continues moving away from the cluster centre. These shocks are considered as promising candidates for powering radio relics found in many clusters. The aim of this paper is to explore the fate of such shocks when they travel to the cluster outskirts, far from the place where the shocks were initiated. In a uniform medium, such a ‘runaway’ shock should weaken with distance. However, as shocks move to large radii in galaxy clusters, the shock is moving down a steep density gradient that helps the shock to maintain its strength over a large distance. Observations and numerical simulations show that, beyond R500, gas density profiles are as steep as, or steeper than, ∼r−3, suggesting that there exists a ‘habitable zone’ for moderately strong shocks in cluster outskirts where the shock strength can be maintained or even amplified. A characteristic feature of runaway shocks is that the strong compression, relative to the initial state, is confined to a narrow region just behind the shock. Therefore, if such a shock runs over a region with a pre-existing population of relativistic particles, then the boost in radio emissivity, due to pure adiabatic compression, will also be confined to a narrow radial shell.

scholarly journals Convergence and scatter of cluster density profiles

2004 ◽  
Vol 353 (2) ◽  
pp. 624-632 ◽  
Author(s):  
Jürg Diemand ◽  
Ben Moore ◽  
Joachim Stadel
Keyword(s):  
Density Profiles ◽  
Cluster Density

scholarly journals Are the globular clusters with significant internal [Fe/H] spreads all former dwarf galaxy nuclei?

2015 ◽  
Vol 11 (S317) ◽  
pp. 110-115 ◽  
Author(s):  
G. S. Da Costa
Keyword(s):  
Distribution Function ◽  
Globular Clusters ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Density Profiles ◽  
Cluster Density ◽  
Galactic Globular Clusters ◽  
Metallicity Distribution

AbstractIn this contribution the hypothesis that the Galactic globular clusters with substantial internal [Fe/H] abundance ranges are the former nuclei of disrupted dwarf galaxies is discussed. Evidence considered includes the form of the metallicity distribution function, the occurrence of large diffuse outer envelopes in cluster density profiles, and the presence of ([s-process/Fe], [Fe/H]) correlations. The hypothesis is shown to be plausible but with the caveat that if significantly more than the current nine clusters known to have [Fe/H] spreads are found, then re-evaluation will be required.

scholarly journals Recovering galaxy cluster gas density profiles with XMM-Newton and Chandra

2017 ◽  
Vol 608 ◽  
pp. A88 ◽  
Author(s):  
I. Bartalucci ◽  
M. Arnaud ◽  
G. W. Pratt ◽  
A. Vikhlinin ◽  
E. Pointecouteau ◽  
...  
Keyword(s):  
Galaxy Cluster ◽  
Correction Method ◽  
Parametric Models ◽  
Quality Data ◽  
Gas Temperature ◽  
Radial Density ◽  
Density Profiles ◽  
X Ray ◽  
Cross Calibration ◽  
The Impact

We examined the reconstruction of galaxy cluster radial density profiles obtained from Chandra and XMM-Newton X-ray observations, using high quality data for a sample of twelve objects covering a range of morphologies and redshifts. By comparing the results obtained from the two observatories and by varying key aspects of the analysis procedure, we examined the impact of instrumental effects and of differences in the methodology used in the recovery of the density profiles. We find that the final density profile shape is particularly robust. We adapted the photon weighting vignetting correction method developed for XMM-Newton for use with Chandra data, and confirm that the resulting Chandra profiles are consistent with those corrected a posteriori for vignetting effects. Profiles obtained from direct deprojection and those derived using parametric models are consistent at the 1% level. At radii larger than ~6″, the agreement between Chandra and XMM-Newton is better than 1%, confirming an excellent understanding of the XMM-Newton PSF. Furthermore, we find no significant energy dependence. The impact of the well-known offset between Chandra and XMM-Newton gas temperature determinations on the density profiles is found to be negligible. However, we find an overall normalisation offset in density profiles of the order of ~2.5%, which is linked to absolute flux cross-calibration issues. As a final result, the weighted ratios of Chandra to XMM-Newton gas masses computed at R2500 and R500 are r = 1.03 ± 0.01 and r = 1.03 ± 0.03, respectively. Our study confirms that the radial density profiles are robustly recovered, and that any differences between Chandra and XMM-Newton can be constrained to the ~2.5% level, regardless of the exact data analysis details. These encouraging results open the way for the true combination of X-ray observations of galaxy clusters, fully leveraging the high resolution of Chandra and the high throughput of XMM-Newton.

scholarly journals The effects of ellipticity and substructure on estimates of cluster density profiles based on lensing and kinematics

2007 ◽  
Vol 381 (1) ◽  
pp. 171-186 ◽  
Author(s):  
Massimo Meneghetti ◽  
Matthias Bartelmann ◽  
Adrian Jenkins ◽  
Carlos Frenk
Keyword(s):  
Density Profiles ◽  
Cluster Density

scholarly journals Cluster density profiles as a test of modified gravity

2012 ◽  
Vol 85 (10) ◽  
Author(s):  
Lucas Lombriser ◽  
Fabian Schmidt ◽  
Tobias Baldauf ◽  
Rachel Mandelbaum ◽  
Uroš Seljak ◽  
...  
Keyword(s):  
Modified Gravity ◽  
Density Profiles ◽  
Cluster Density
Sign in / Sign up

Export Citation Format

Share Document