scholarly journals Importance of Cluster Structural Evolution in Using X‐Ray and Sunyaev‐Zeldovich Effect Galaxy Cluster Surveys to Study Dark Energy

2003 ◽  
Vol 585 (2) ◽  
pp. 603-610 ◽  
Author(s):  
Subhabrata Majumdar ◽  
Joseph J. Mohr
Keyword(s):  
Dark Energy ◽  
Structural Evolution ◽  
Galaxy Cluster ◽  
X Ray

scholarly journals Constraining the dark energy with galaxy cluster x-ray data

2003 ◽  
Vol 68 (2) ◽  
Author(s):  
J. A. S. Lima ◽  
J. V. Cunha ◽  
J. S. Alcaniz
Keyword(s):  
Dark Energy ◽  
Galaxy Cluster ◽  
X Ray

scholarly journals Stellar mass as a galaxy cluster mass proxy: application to the Dark Energy Survey redMaPPer clusters

2020 ◽  
Vol 493 (4) ◽  
pp. 4591-4606 ◽  
Author(s):  
A Palmese ◽  
J Annis ◽  
J Burgad ◽  
A Farahi ◽  
M Soares-Santos ◽  
...  
Keyword(s):  
Dark Energy ◽  
Bayesian Model Averaging ◽  
Galaxy Cluster ◽  
Wide Field ◽  
X Ray ◽  
Mass Scaling ◽  
Cluster Mass ◽  
Dark Energy Survey ◽  
Stellar Masses ◽  
Energy Survey

Abstract We introduce a galaxy cluster mass observable, μ⋆, based on the stellar masses of cluster members, and we present results for the Dark Energy Survey (DES) Year 1 (Y1) observations. Stellar masses are computed using a Bayesian model averaging method, and are validated for DES data using simulations and COSMOS data. We show that μ⋆ works as a promising mass proxy by comparing our predictions to X-ray measurements. We measure the X-ray temperature–μ⋆ relation for a total of 129 clusters matched between the wide-field DES Y1 redMaPPer catalogue and Chandra and XMM archival observations, spanning the redshift range 0.1 < $z$ < 0.7. For a scaling relation that is linear in logarithmic space, we find a slope of α = 0.488 ± 0.043 and a scatter in the X-ray temperature at fixed μ⋆ of $\sigma _{{\rm ln} T_\mathrm{ X}|\mu _\star }= 0.266^{+0.019}_{-0.020}$ for the joint sample. By using the halo mass scaling relations of the X-ray temperature from the Weighing the Giants program, we further derive the μ⋆-conditioned scatter in mass, finding $\sigma _{{\rm ln} M|\mu _\star }= 0.26^{+ 0.15}_{- 0.10}$. These results are competitive with well-established cluster mass proxies used for cosmological analyses, showing that μ⋆ can be used as a reliable and physically motivated mass proxy to derive cosmological constraints.

scholarly journals Dark Energy Surveyed Year 1 results: calibration of cluster mis-centring in the redMaPPer catalogues

2019 ◽  
Vol 487 (2) ◽  
pp. 2578-2593 ◽  
Author(s):  
Y Zhang ◽  
T Jeltema ◽  
D L Hollowood ◽  
S Everett ◽  
E Rozo ◽  
...  
Keyword(s):  
Dark Energy ◽  
Gamma Distribution ◽  
Galaxy Cluster ◽  
Weak Lensing ◽  
Descriptive Model ◽  
X Ray ◽  
Projected Distance

Abstract The centre determination of a galaxy cluster from an optical cluster finding algorithm can be offset from theoretical prescriptions or N-body definitions of its host halo centre. These offsets impact the recovered cluster statistics, affecting both richness measurements and the weak lensing shear profile around the clusters. This paper models the centring performance of the redMaPPer cluster finding algorithm using archival X-ray observations of redMaPPer-selected clusters. Assuming the X-ray emission peaks as the fiducial halo centres, and through analysing their offsets to the redMaPPer centres, we find that ${\sim } 75\pm 8 {{\ \rm per\ cent}}$ of the redMaPPer clusters are well centred and the mis-centred offset follows a Gamma distribution in normalized, projected distance. These mis-centring offsets cause a systematic underestimation of cluster richness relative to the well-centred clusters, for which we propose a descriptive model. Our results enable the DES Y1 cluster cosmology analysis by characterizing the necessary corrections to both the weak lensing and richness abundance functions of the DES Y1 redMaPPer cluster catalogue.

scholarly journals Mass variance from archival X-ray properties of Dark Energy Survey Year-1 galaxy clusters

2019 ◽  
Vol 490 (3) ◽  
pp. 3341-3354 ◽  
Author(s):  
A Farahi ◽  
X Chen ◽  
A E Evrard ◽  
D L Hollowood ◽  
R Wilkinson ◽  
...  
Keyword(s):  
Dark Energy ◽  
Confidence Region ◽  
Galaxy Cluster ◽  
Mass Relation ◽  
X Ray ◽  
Dark Energy Survey ◽  
Two Samples ◽  
Scaling Parameters ◽  
Intrinsic Scatter ◽  
Energy Survey

ABSTRACT Using archival X-ray observations and a lognormal population model, we estimate constraints on the intrinsic scatter in halo mass at fixed optical richness for a galaxy cluster sample identified in Dark Energy Survey Year-One (DES-Y1) data with the redMaPPer algorithm. We examine the scaling behaviour of X-ray temperatures, TX, with optical richness, λRM, for clusters in the redshift range 0.2 < z < 0.7. X-ray temperatures are obtained from Chandra and XMM observations for 58 and 110 redMaPPer systems, respectively. Despite non-uniform sky coverage, the TX measurements are $\gt 50{{\ \rm per\ cent}}$ complete for clusters with λRM > 130. Regression analysis on the two samples produces consistent posterior scaling parameters, from which we derive a combined constraint on the residual scatter, $\sigma _{\ln T \, |\, \lambda }= 0.275 \pm 0.019$. Joined with constraints for TX scaling with halo mass from the Weighing the Giants program and richness–temperature covariance estimates from the LoCuSS sample, we derive the richness-conditioned scatter in mass, $\sigma _{\ln M \, |\, \lambda }= 0.30 \pm 0.04\, _{({\rm stat})} \pm 0.09\, _{({\rm sys})}$, at an optical richness of approximately 100. Uncertainties in external parameters, particularly the slope and variance of the TX–mass relation and the covariance of TX and λRM at fixed mass, dominate the systematic error. The $95{{\ \rm per\ cent}}$ confidence region from joint sample analysis is relatively broad, $\sigma _{\ln M \, |\, \lambda }\in [0.14, \, 0.55]$, or a factor 10 in variance.

scholarly journals Galaxy cluster cosmology from X-ray surveys of the hot and energetic Universe

2015 ◽  
Vol 11 (A29B) ◽  
pp. 79-90
Author(s):  
Nicolas Clerc ◽  
Barbara Sartoris ◽  
Klaus Dolag ◽  
Rukmani Vijayaraghavan ◽  
Veronica Biffi
Keyword(s):  
Dark Energy ◽  
Numerical Simulations ◽  
Galaxy Clusters ◽  
Galaxy Cluster ◽  
X Ray ◽  
Recent Advances ◽  
Evolution With Time

AbstractWe discuss recent advances and prospects in our understanding of the formation of structures on cosmic scales based on surveys of galaxy clusters in the X-ray bands. We highlight the interaction between observations and numerical simulations of the X-ray sky. We show how future surveys will unveil the nature of the dark energy and study its evolution with time.

STRUCTURAL EVOLUTION OF EXCEPTIONALLY IRON-DEFICIENT HEMATITE NANOCRYSTALS AS OBSERVED BY IN SITU SYNCHROTRON X-RAY DIFFRACTION

2019 ◽  
Author(s):  
Si Athena Chen ◽  
◽  
Peter Heaney ◽  
Jeffrey E. Post ◽  
Peter J. Eng ◽  
...  
Keyword(s):  
Structural Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Deficient

An X-Ray–Selected Galaxy Cluster at [CLC][ITAL]z[/ITAL][/CLC] = 1.26

1999 ◽  
Vol 118 (1) ◽  
pp. 76-85 ◽  
Author(s):  
Piero Rosati ◽  
S. A. Stanford ◽  
Peter R. Eisenhardt ◽  
Richard Elston ◽  
Hyron Spinrad ◽  
...  
Keyword(s):  
Galaxy Cluster ◽  
X Ray

scholarly journals The role of AGN activity in the building up of the BCG at z ∼ 1.6

2019 ◽  
Vol 15 (S356) ◽  
pp. 280-284
Author(s):  
Angela Bongiorno ◽  
Andrea Travascio
Keyword(s):  
Galaxy Cluster ◽  
Cluster Galaxy ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Star Forming ◽  
The Core ◽  
The Galaxy ◽  
Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

scholarly journals Effect of tungsten disulfide nanotubes on crystallization of polylactide under uniaxial deformation and annealing

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Fausta Loffredo ◽  
Loredana Tammaro ◽  
Tiziana Di Luccio ◽  
Carmela Borriello ◽  
Fulvia Villani ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Structural Evolution ◽  
Tungsten Disulfide ◽  
Fine Tuning ◽  
Nanocomposite Films ◽  
Uniaxial Deformation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering

AbstractTungsten disulfide (WS2) nanotubes (NTs) are examined here as a filler for polylactide (PLA) for their ability to accelerate PLA crystallization and for their promising biocompatibility in relevant to biomedical applications of PLA-WS2 nanocomposites. In this work, we have studied the structural and thermal properties of PLA-WS2 nanocomposite films varying the concentration of WS2 NTs from 0 (neat PLA) to 0.6 wt%. The films were uniaxially drawn at 90 °C and annealed at the same temperature for 3 and 10 min. Using wide angle x-ray scattering, Raman spectroscopy and differential scanning calorimetry, we probed the effects of WS2 NT addition on the structure of the PLA films at various stages of processing (unstretched, stretching, annealing). We found that 0.6 wt% of WS2 induces the same level of crystallinity in as stretched PLA-WS2 as annealing in neat PLA for 10 min. These data provide useful insights into the role of WS2 NTs on the structural evolution of PLA-WS2 composites under uniaxial deformation, and extend their applicability to situations where fine tuning of PLA crystallinity is desirable.

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