scholarly journals Stellar mass to halo mass scaling relation for X-ray-selected low-mass galaxy clusters and groups out to redshiftz≈ 1

2016 ◽  
Vol 458 (1) ◽  
pp. 379-393 ◽  
Author(s):  
I. Chiu ◽  
A. Saro ◽  
J. Mohr ◽  
S. Desai ◽  
S. Bocquet ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Stellar Mass ◽  
Scaling Relation ◽  
X Ray ◽  
Mass Scaling ◽  
Low Mass

scholarly journals THE STELLAR MASS–HALO MASS RELATION FOR LOW-MASS X-RAY GROUPS AT 0.5< z < 1 IN THE CDFS WITH CSI

2015 ◽  
Vol 799 (2) ◽  
pp. L17 ◽  
Author(s):  
Shannon G. Patel ◽  
Daniel D. Kelson ◽  
Rik J. Williams ◽  
John S. Mulchaey ◽  
Alan Dressler ◽  
...  
Keyword(s):  
Stellar Mass ◽  
Mass Relation ◽  
X Ray ◽  
Low Mass

The AGN dependence on cluster mass

2018 ◽  
Vol 14 (S342) ◽  
pp. 145-148
Author(s):  
Elias Koulouridis ◽  
Keyword(s):  
Galaxy Clusters ◽  
High Velocity ◽  
High Redshift ◽  
High Mass ◽  
X Ray ◽  
Cluster Galaxies ◽  
Cluster Mass ◽  
Bona Fide ◽  
Low Mass ◽  
Velocity Dispersions

AbstractWe present the results of a study of the AGN density in a homogeneous and well studied sample of 167 bona-fide X-ray galaxy clusters (0.1<z<0.5). Our aim is to study the AGN activity in 167 XXL X-ray galaxy clusters as a function of the cluster mass and the location of the AGN in the cluster. We report a significant AGN excess in our low-mass cluster sub-sample between 0.5r500 and 2r500. In contrast, the high-mass sub-sample presents no AGN excess. The AGN excess in poor clusters indicates AGN triggering, supporting previous studies that reported enhanced galaxy merging in the cluster outskirts. This effect is probably prevented by high velocity dispersions in high-mass clusters. Comparing also with previous studies of massive or high-redshift clusters, we conclude that the AGN fraction in cluster galaxies anti-correlates strongly with cluster mass.

scholarly journals Covariance in the thermal SZ–weak lensing mass scaling relation of galaxy clusters

2016 ◽  
Vol 460 (4) ◽  
pp. 3913-3924 ◽  
Author(s):  
Masato Shirasaki ◽  
Daisuke Nagai ◽  
Erwin T. Lau
Keyword(s):  
Galaxy Clusters ◽  
Weak Lensing ◽  
Scaling Relation ◽  
Mass Scaling

scholarly journals Manufacturing cosmic rays in the evolving dynamical states of galaxy clusters

2019 ◽  
Vol 488 (1) ◽  
pp. 1301-1319 ◽  
Author(s):  
Reju Sam John ◽  
Surajit Paul ◽  
Luigi Iapichino ◽  
Karl Mannheim ◽  
Harish Kumar
Keyword(s):  
Cosmic Rays ◽  
Galaxy Clusters ◽  
Theoretical Calculations ◽  
Shock Acceleration ◽  
Diffusive Shock Acceleration ◽  
X Ray ◽  
Mass Scaling ◽  
Dynamical Phase ◽  
The Galaxy ◽  
High Mach

ABSTRACT Galaxy clusters are known to be reservoirs of cosmic rays (CRs), as inferred from theoretical calculations or detection of CR-derived observables. CR acceleration in clusters is mostly attributed to the dynamical activity that produces shocks. Shocks in clusters emerge out of merger or accretion, but which one is more effective in producing CRs? at which dynamical phase? and why? To this aim, we study the production or injection of CRs through shocks and its evolution in the galaxy clusters using cosmological simulations with the enzo code. Particle acceleration model considered here is primarily the Diffusive Shock Acceleration (DSA) of thermal particles, but we also report a tentative study with pre-existing CRs. Defining appropriate dynamical states using the concept of virialization, we studied a sample of merging and non-merging clusters. We report that the merger shocks (with Mach number $\mathcal {M}\sim 2-5$) are the most effective CR producers, while high-Mach peripheral shocks (i.e. $\mathcal {M}\gt 5$) are mainly responsible for the brightest phase of CR injection in clusters. Clusters once merged, permanently deviate from CR and X-ray mass scaling of non-merging systems, enabling us to use it as a tool to determine the state of merger. Through a temporal and spatial evolution study, we found a strong correlation between cluster merger dynamics and CR injection. We observed that the brightest phase of X-ray and CR injection from clusters occurs, respectively, at about 1.0 and 1.5 Gyr after every mergers, and CR injection peaks near to the cluster virial radius (i.e r200). Delayed CR injection peaks found in this study deserve further investigation for possible impact on the evolution of CR-derived observables from galaxy clusters.

scholarly journals Mass calibration of the CODEX cluster sample using SPIDERS spectroscopy – I. The richness–mass relation

2019 ◽  
Vol 486 (2) ◽  
pp. 1594-1607 ◽  
Author(s):  
R Capasso ◽  
J J Mohr ◽  
A Saro ◽  
A Biviano ◽  
N Clerc ◽  
...  
Keyword(s):  
Matched Filter ◽  
Mass Relation ◽  
Scaling Relation ◽  
Cluster Galaxy ◽  
X Ray ◽  
Mass Scaling ◽  
Sky Survey ◽  
The Impact ◽  
Parameter Constraints ◽  
Red Sequence

Abstract We use galaxy dynamical information to calibrate the richness–mass scaling relation of a sample of 428 galaxy clusters that are members of the CODEX sample with redshifts up to z ∼ 0.7. These clusters were X-ray selected using the ROSAT All-Sky Survey (RASS) and then cross-matched to associated systems in the redMaPPer (the red sequence Matched-filter Probabilistic Percolation) catalogue from the Sloan Digital Sky Survey. The spectroscopic sample we analyse was obtained in the SPIDERS program and contains ∼7800 red member galaxies. Adopting NFW mass and galaxy density profiles and a broad range of orbital anisotropy profiles, we use the Jeans equation to calculate halo masses. Modelling the scaling relation as $\lambda \propto \text{A}_{\lambda } {M_{\text{200c}}}^{\text{B}_{\lambda }} ({1+z})^{\gamma _{\lambda }}$, we find the parameter constraints $\text{A}_{\lambda }=38.6^{+3.1}_{-4.1}\pm 3.9$, $\text{B}_{\lambda }=0.99^{+0.06}_{-0.07}\pm 0.04$, and $\gamma _{\lambda }=-1.13^{+0.32}_{-0.34}\pm 0.49$, where we present systematic uncertainties as a second component. We find good agreement with previously published mass trends with the exception of those from stacked weak lensing analyses. We note that although the lensing analyses failed to account for the Eddington bias, this is not enough to explain the differences. We suggest that differences in the levels of contamination between pure redMaPPer and RASS + redMaPPer samples could well contribute to these differences. The redshift trend we measure is more negative than but statistically consistent with previous results. We suggest that our measured redshift trend reflects a change in the cluster galaxy red sequence (RS) fraction with redshift, noting that the trend we measure is consistent with but somewhat stronger than an independently measured redshift trend in the RS fraction. We also examine the impact of a plausible model of correlated scatter in X-ray luminosity and optical richness, showing it has negligible impact on our results.

scholarly journals ON THE BLACK HOLE MASS—X-RAY EXCESS VARIANCE SCALING RELATION FOR ACTIVE GALACTIC NUCLEI IN THE LOW-MASS REGIME

2015 ◽  
Vol 808 (2) ◽  
pp. 163 ◽  
Author(s):  
Hai-Wu Pan ◽  
Weimin Yuan ◽  
Xin-Lin Zhou ◽  
Xiao-Bo Dong ◽  
Bifang Liu
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Scaling Relation ◽  
Black Hole Mass ◽  
X Ray ◽  
Low Mass

scholarly journals Why are some galaxy clusters underluminous?

2019 ◽  
Vol 630 ◽  
pp. A78 ◽  
Author(s):  
S. Andreon ◽  
A. Moretti ◽  
G. Trinchieri ◽  
C. H. Ishwara-Chandra
Keyword(s):  
Electron Density ◽  
Galaxy Clusters ◽  
Stellar Mass ◽  
Electron Density Profile ◽  
Sloan Digital Sky Survey ◽  
Radial Dependence ◽  
X Ray ◽  
Low Concentration ◽  
Electron Density Profiles ◽  
Low X

Our knowledge of the variety of galaxy clusters has been increasing in the last few years thanks to our progress in understanding the severity of selection effects on samples. To understand the reason for the observed variety, we study CL2015, a cluster (log M500/M⊙ = 14.39) easily missed in X-ray selected observational samples. Its core-excised X-ray luminosity is low for its mass M500, well below the mean relation for an X-ray selected sample, but only ∼1.5σ below that derived for an X-ray unbiased sample. We derived thermodynamic profiles and hydrostatic masses with the acquired deep Swift X-ray data, and we used archival Einstein, Planck, and Sloan Digital Sky Survey data to derive additional measurements, such as integrated Compton parameter, total mass, and stellar mass. The pressure and the electron density profiles of CL2015 are systematically outside the ±2σ range of the universal profiles; in particular the electron density profile is even lower than the one derived from Planck-selected clusters. CL2015 also turns out to be fairly different in the X-ray luminosity vs. integrated pressure scaling compared to an X-ray selected sample, but it is a normal object in terms of stellar mass fraction. CL2015’s hydrostatic mass profile, by itself or when is considered together with dynamical masses, shows that the cluster has an unusual low concentration and an unusual sparsity compared to clusters in X-ray selected samples. The different behavior of CL2015 is caused by its low concentration. When concentration differences are accounted for, the properties of CL2015 become consistent with comparison samples. CL2015 is perhaps the first known cluster with a remarkably low mass concentration for which high quality X-ray data exist. Objects similar to CL2015 fail to enter observational X-ray selected samples because of their low X-ray luminosity relative to their mass. The different radial dependence of various observables is a promising way to collect other examples of low concentration clusters.

scholarly journals Do Magnetic Fields Actually Inflate Low-Mass Stars?

2013 ◽  
Vol 9 (S302) ◽  
pp. 150-153
Author(s):  
Gregory A. Feiden ◽  
Brian Chaboyer
Keyword(s):  
Magnetic Fields ◽  
Eclipsing Binaries ◽  
Scaling Relation ◽  
Model Surface ◽  
Outer Envelope ◽  
Low Mass Stars ◽  
Convective Boundary ◽  
X Ray ◽  
Surface Magnetic Field ◽  
Low Mass

AbstractMagnetic fields have been hypothesized to inflate the radii of low-mass stars—defined as less than 0.8 M⊙–in detached eclipsing binaries (DEBs). We evaluate this hypothesis using the magnetic Dartmouth stellar evolution code. Results suggest that magnetic suppression of thermal convection can inflate low-mass stars that possess a radiative core and convective outer envelope. A scaling relation between X-ray luminosity and surface magnetic flux indicates that model surface magnetic field strength predictions are consistent with observations. This supports the notion that magnetic fields may be inflating these stars. However, magnetic models are unable to reproduce radii of fully convective stars in DEBs. Instead, we propose that model discrepancies below the fully convective boundary are related to metallicity.

scholarly journals Validation of selection function, sample contamination and mass calibration in galaxy cluster samples

2020 ◽  
Vol 498 (1) ◽  
pp. 771-798
Author(s):  
S Grandis ◽  
M Klein ◽  
J J Mohr ◽  
S Bocquet ◽  
M Paulus ◽  
...  
Keyword(s):  
Cosmological Parameters ◽  
Galaxy Cluster ◽  
Selection Function ◽  
Scaling Relation ◽  
X Ray ◽  
Mass Scaling ◽  
Dark Energy Survey ◽  
Cross Calibration ◽  
Number Counts

ABSTRACT We construct and validate the selection function of the MARD-Y3 galaxy cluster sample. This sample was selected through optical follow-up of the 2nd ROSAT faint source catalogue with Dark Energy Survey year 3 data. The selection function is modelled by combining an empirically constructed X-ray selection function with an incompleteness model for the optical follow-up. We validate the joint selection function by testing the consistency of the constraints on the X-ray flux–mass and richness–mass scaling relation parameters derived from different sources of mass information: (1) cross-calibration using South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) clusters, (2) calibration using number counts in X-ray, in optical and in both X-ray and optical while marginalizing over cosmological parameters, and (3) other published analyses. We find that the constraints on the scaling relation from the number counts and SPT-SZ cross-calibration agree, indicating that our modelling of the selection function is adequate. Furthermore, we apply a largely cosmology independent method to validate selection functions via the computation of the probability of finding each cluster in the SPT-SZ sample in the MARD-Y3 sample and vice versa. This test reveals no clear evidence for MARD-Y3 contamination, SPT-SZ incompleteness or outlier fraction. Finally, we discuss the prospects of the techniques presented here to limit systematic selection effects in future cluster cosmological studies.

scholarly journals The redshift evolution of X-ray and Sunyaev–Zel’dovich scaling relations in the fable simulations

2019 ◽  
Vol 489 (2) ◽  
pp. 2439-2470 ◽  
Author(s):  
Nicholas A Henden ◽  
Ewald Puchwein ◽  
Debora Sijacki
Keyword(s):  
High Redshift ◽  
Scaling Relations ◽  
Observational Constraints ◽  
Lower Mass ◽  
X Ray ◽  
Galaxy Groups ◽  
Mass Scaling ◽  
Low Mass ◽  
Hydrodynamical Simulations ◽  
Intrinsic Scatter

Abstract We study the redshift evolution of the X-ray and Sunyaev–Zel’dovich (SZ) scaling relations for galaxy groups and clusters in the fable suite of cosmological hydrodynamical simulations. Using an expanded sample of 27 high-resolution zoom-in simulations, together with a uniformly sampled cosmological volume to sample low-mass systems, we find very good agreement with the majority of observational constraints up to z ∼ 1. We predict significant deviations of all examined scaling relations from the simple self-similar expectations. While the slopes are approximately independent of redshift, the normalizations evolve positively with respect to self-similarity, even for commonly used mass proxies such as the YX parameter. These deviations are due to a combination of factors, including more effective active galactic nuclei feedback in lower mass haloes, larger binding energy of gas at a given halo mass at higher redshifts, and larger non-thermal pressure support from kinetic motions at higher redshifts. Our results have important implications for cluster cosmology from upcoming SZ surveys such as SPT-3G, ACTpol, and CMB-S4, as relatively small changes in the observable–mass scaling relations (within theoretical uncertainties) have a large impact on the predicted number of high-redshift clusters and hence on our ability to constrain cosmology using cluster abundances. In addition, we find that the intrinsic scatter of the relations, which agrees well with most observational constraints, increases at lower redshifts and for lower mass systems. This calls for a more complex parametrization than adopted in current observational studies to be able to accurately account for selection biases.

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