scholarly journals AGN Triggering in the Infall Regions of Distant X-Ray Luminous Galaxy Clusters at0.9

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
R. Fassbender ◽  
R. Šuhada ◽  
A. Nastasi
Keyword(s):  
Point Source ◽  
Galaxy Clusters ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Point Sources ◽  
Cluster Radius ◽  
X Ray ◽  
Full Band ◽  
Triggering Mechanisms

Observational constraints on the average radial distribution profile of AGN in distant galaxy clusters can provide important clues on the triggering mechanisms of AGN activity in dense environments and are essential for a completeness evaluation of cluster selection techniques in the X-ray and mm wavebands. The aim of this work is a statistical study with XMM-Newtonof the presence and distribution of X-ray AGN in the large-scale structure environments of 22 X-ray luminous galaxy clusters in the redshift range0.9<z≲1.6compiled by the XMM-NewtonDistant Cluster Project (XDCP). To this end, the X-ray point source lists from detections in the soft band (0.35–2.4 keV) and full band (0.3–7.5 keV) were stacked in cluster-centric coordinates and compared to average background number counts extracted from three independent control fields in the same observations. A significant full-band (soft-band) excess of ∼78 (67) X-ray point sources is found in the cluster fields within an angular distance of8′(4 Mpc) at a statistical confidence level of 4.0σ (4.2σ), corresponding to an average number of detected excess AGN per cluster environment of 3.5 ± 0.9 (3.0 ± 0.7). The data point towards a rising radial profile in the cluster region (r<1 Mpc) of predominantly low-luminosity AGN with an average detected excess of about one point source per system, with a tentative preferred occurrence along the main cluster elongation axis. A second statistically significant overdensity of brighter soft-band-detected AGN is found at cluster-centric distances of 4′–6′(2-3 Mpc), corresponding to about three times the average cluster radiusR200of the systems. If confirmed, these results would support the idea of two different physical triggering mechanisms of X-ray AGN activity in dependence of the radially changing large-scale structure environment of the distant clusters. For high-zcluster studies at lower spatial resolution with the upcoming eROSITA all-sky X-ray survey, the results suggest that cluster-associated X-ray AGN may impose a bias in the spectral analysis of high-zsystems, while their detection and flux measurements in the soft band may not be significantly affected.

scholarly journals X-ray Cluster Large Scale Structure and Cosmology

2005 ◽  
Vol 216 ◽  
pp. 373-380
Author(s):  
Marguerite Pierre
Keyword(s):  
Dark Energy ◽  
Galaxy Clusters ◽  
Large Scale ◽  
Scaling Law ◽  
Large Scale Structure ◽  
Short Review ◽  
Scale Structure ◽  
X Ray ◽  
Recent Advances

We outline the main arguments in favor of cosmological X-ray surveys of galaxy clusters. We summarize recent advances in our understanding of cluster physics. After a short review of past surveys, we present the scientific motivations of the XMM Large Scale Structure survey. We further illustrate how such a survey can help constrain the nature of the dark energy as well as cluster scaling law evolution, i.e. non-gravitational physics.

X-ray galaxy clusters in the large-scale structure

2004 ◽  
Vol 2004 (IAUC195) ◽  
Author(s):  
H Böhringer ◽  
P Schuecker ◽  
N. Nowak ◽  
P. Popesso ◽  
M. Huber
Keyword(s):  
Galaxy Clusters ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
X Ray

scholarly journals The XMM-Large Scale Structure catalogue: X-ray sources and associated optical data. Version I

2007 ◽  
Vol 382 (1) ◽  
pp. 279-290 ◽  
Author(s):  
M. Pierre ◽  
L. Chiappetti ◽  
F. Pacaud ◽  
A. Gueguen ◽  
C. Libbrecht ◽  
...  
Keyword(s):  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Optical Data ◽  
X Ray

scholarly journals Constraints on neutrino masses from the study of the nearby large-scale structure and galaxy cluster counts

2016 ◽  
Vol 31 (21) ◽  
pp. 1640008 ◽  
Author(s):  
Hans Böhringer ◽  
Gayoung Chon
Keyword(s):  
Large Scale ◽  
Cosmological Parameters ◽  
Large Scale Structure ◽  
Matter Density ◽  
Density Fluctuations ◽  
Scale Structure ◽  
Neutrino Masses ◽  
Microwave Background ◽  
X Ray ◽  
Massive Neutrinos

The high precision measurements of the cosmic microwave background by the Planck survey yielded tight constraints on cosmological parameters and the statistics of the density fluctuations at the time of recombination. This provides the means for a critical study of structure formation in the Universe by comparing the microwave background results with present epoch measurements of the cosmic large-scale structure. It can reveal subtle effects such as how different forms of Dark Matter may modify structure growth. Currently most interesting is the damping effect of structure growth by massive neutrinos. Different observations of low redshift matter density fluctuations provided evidence for a signature of massive neutrinos. Here we discuss the study of the cosmic large-scale structure with a complete sample of nearby, X-ray luminous clusters from our REFLEX cluster survey. From the observed X-ray luminosity function and its reproduction for different cosmological models, we obtain tight constraints on the cosmological parameters describing the matter density, [Formula: see text], and the density fluctuation amplitude, [Formula: see text]. A comparison of these constraints with the Planck results shows a discrepancy in the framework of a pure [Formula: see text]CDM model, but the results can be reconciled, if we allow for a neutrino mass in the range of 0.17 eV to 0.7 eV. Also some others, but not all of the observations of the nearby large-scale structure provide evidence or trends for signatures of massive neutrinos. With further improvement in the systematics and future survey projects, these indications will develop into a definitive measurement of neutrino masses.

scholarly journals Planck intermediate results

2018 ◽  
Vol 617 ◽  
pp. A48 ◽  
Author(s):  
◽  
N. Aghanim ◽  
Y. Akrami ◽  
M. Ashdown ◽  
J. Aumont ◽  
...  
Keyword(s):  
Large Scale ◽  
Direct Evidence ◽  
Velocity Dispersion ◽  
Matched Filter ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
Statistical Homogeneity ◽  
Cross Correlations

Using the Planck full-mission data, we present a detection of the temperature (and therefore velocity) dispersion due to the kinetic Sunyaev-Zeldovich (kSZ) effect from clusters of galaxies. To suppress the primary CMB and instrumental noise we derive a matched filter and then convolve it with the Planck foreground-cleaned “2D-ILC” maps. By using the Meta Catalogue of X-ray detected Clusters of galaxies (MCXC), we determine the normalized rms dispersion of the temperature fluctuations at the positions of clusters, finding that this shows excess variance compared with the noise expectation. We then build an unbiased statistical estimator of the signal, determining that the normalized mean temperature dispersion of 1526 clusters is 〈(ΔT/T)2 〉 = (1.64 ± 0.48) × 10−11. However, comparison with analytic calculations and simulations suggest that around 0.7 σ of this result is due to cluster lensing rather than the kSZ effect. By correcting this, the temperature dispersion is measured to be 〈(ΔT/T)2〉 = (1.35 ± 0.48) × 10−11, which gives a detection at the 2.8 σ level. We further convert uniform-weight temperature dispersion into a measurement of the line-of-sight velocity dispersion, by using estimates of the optical depth of each cluster (which introduces additional uncertainty into the estimate). We find that the velocity dispersion is 〈υ2〉 = (123 000 ± 71 000) (km s−1)2, which is consistent with findings from other large-scale structure studies, and provides direct evidence of statistical homogeneity on scales of 600 h−1 Mpc. Our study shows the promise of using cross-correlations of the kSZ effect with large-scale structure in order to constrain the growth of structure.

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