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 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 Galaxies in X-ray selected clusters and groups in Dark Energy Survey data – II. Hierarchical Bayesian modelling of the red-sequence galaxy luminosity function

2019 ◽  
Vol 488 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Y Zhang ◽  
C J Miller ◽  
P Rooney ◽  
A Bermeo ◽  
A K Romer ◽  
...  
Keyword(s):  
Dark Energy ◽  
Luminosity Function ◽  
Hierarchical Bayesian ◽  
Cluster Galaxy ◽  
X Ray ◽  
Cluster Mass ◽  
Dark Energy Survey ◽  
The Individual ◽  
Energy Survey ◽  
Red Sequence

Abstract Using ∼100 X-ray selected clusters in the Dark Energy Survey Science Verification data, we constrain the luminosity function (LF) of cluster red-sequence galaxies as a function of redshift. This is the first homogeneous optical/X-ray sample large enough to constrain the evolution of the LF simultaneously in redshift (0.1 < z < 1.05) and cluster mass ($13.5 \le \rm {log_{10}}(M_{200crit}) \sim \lt 15.0$). We pay particular attention to completeness issues and the detection limit of the galaxy sample. We then apply a hierarchical Bayesian model to fit the cluster galaxy LFs via a Schechter function, including its characteristic break (m*) to a faint end power-law slope (α). Our method enables us to avoid known issues in similar analyses based on stacking or binning the clusters. We find weak and statistically insignificant (∼1.9σ) evolution in the faint end slope α versus redshift. We also find no dependence in α or m* with the X-ray inferred cluster masses. However, the amplitude of the LF as a function of cluster mass is constrained to ${\sim } 20{{\ \rm per\ cent}}$ precision. As a by-product of our algorithm, we utilize the correlation between the LF and cluster mass to provide an improved estimate of the individual cluster masses as well as the scatter in true mass given the X-ray inferred masses. This technique can be applied to a larger sample of X-ray or optically selected clusters from the Dark Energy Survey, significantly improving the sensitivity of the analysis.

scholarly journals Dark Energy Survey Year 1 Results: Wide-field mass maps via forward fitting in harmonic space

2020 ◽  
Vol 493 (4) ◽  
pp. 5662-5679 ◽  
Author(s):  
B Mawdsley ◽  
D Bacon ◽  
C Chang ◽  
P Melchior ◽  
E Rozo ◽  
...  
Keyword(s):  
Dark Energy ◽  
Mapping Technique ◽  
Harmonic Space ◽  
Wide Field ◽  
Direct Inversion ◽  
Dark Energy Survey ◽  
Central Regions ◽  
Fitting In ◽  
Energy Survey ◽  
Good Agreement

ABSTRACT We present new wide-field weak lensing mass maps for the Year 1 Dark Energy Survey (DES) data, generated via a forward fitting approach. This method of producing maps does not impose any prior constraints on the mass distribution to be reconstructed. The technique is found to improve the map reconstruction on the edges of the field compared to the conventional Kaiser–Squires method, which applies a direct inversion on the data; our approach is in good agreement with the previous direct approach in the central regions of the footprint. The mapping technique is assessed and verified with tests on simulations; together with the Kaiser–Squires method, the technique is then applied to data from the DES Year 1 data and the differences between the two methods are compared. We also produce the first DES measurements of the convergence Minkowski functionals and compare them to those measured in simulations.

scholarly journals Wide-Field Lensing Mass Maps from Dark Energy Survey Science Verification Data

2015 ◽  
Vol 115 (5) ◽  
Author(s):  
C. Chang ◽  
V. Vikram ◽  
B. Jain ◽  
D. Bacon ◽  
A. Amara ◽  
...  
Keyword(s):  
Dark Energy ◽  
Wide Field ◽  
Dark Energy Survey ◽  
Energy Survey

scholarly journals Dark Energy Survey Year 1 results: validation of weak lensing cluster member contamination estimates from P(z) decomposition

2019 ◽  
Vol 489 (2) ◽  
pp. 2511-2524 ◽  
Author(s):  
T N Varga ◽  
J DeRose ◽  
D Gruen ◽  
T McClintock ◽  
S Seitz ◽  
...  
Keyword(s):  
Dark Energy ◽  
Decomposition Method ◽  
Weak Lensing ◽  
Cluster Member ◽  
Photometric Redshift ◽  
Cluster Mass ◽  
Dark Energy Survey ◽  
Mass Calibration ◽  
The Masses ◽  
Energy Survey

ABSTRACT Weak lensing source galaxy catalogues used in estimating the masses of galaxy clusters can be heavily contaminated by cluster members, prohibiting accurate mass calibration. In this study, we test the performance of an estimator for the extent of cluster member contamination based on decomposing the photometric redshift P(z) of source galaxies into contaminating and background components. We perform a full scale mock analysis on a simulated sky survey approximately mirroring the observational properties of the Dark Energy Survey Year One observations (DES Y1), and find excellent agreement between the true number profile of contaminating cluster member galaxies in the simulation and the estimated one. We further apply the method to estimate the cluster member contamination for the DES Y1 redMaPPer cluster mass calibration analysis, and compare the results to an alternative approach based on the angular correlation of weak lensing source galaxies. We find indications that the correlation based estimates are biased by the selection of the weak lensing sources in the cluster vicinity, which does not strongly impact the P(z) decomposition method. Collectively, these benchmarks demonstrate the strength of the P(z) decomposition method in alleviating membership contamination and enabling highly accurate cluster weak lensing studies without broad exclusion of source galaxies, thereby improving the total constraining power of cluster mass calibration via weak lensing.

scholarly journals Wide-field lensing mass maps from Dark Energy Survey science verification data: Methodology and detailed analysis

2015 ◽  
Vol 92 (2) ◽  
Author(s):  
V. Vikram ◽  
C. Chang ◽  
B. Jain ◽  
D. Bacon ◽  
A. Amara ◽  
...  
Keyword(s):  
Dark Energy ◽  
Detailed Analysis ◽  
Wide Field ◽  
Dark Energy Survey ◽  
Energy Survey

scholarly journals A general framework to test gravity using galaxy clusters III: Observable-mass scaling relations in f(R) gravity

2021 ◽  
Author(s):  
Myles A Mitchell ◽  
Christian Arnold ◽  
Baojiu Li
Keyword(s):  
Galaxy Formation ◽  
General Framework ◽  
Accurate Determination ◽  
Galaxy Cluster ◽  
Scaling Relations ◽  
Gas Temperature ◽  
Temperature Relation ◽  
X Ray ◽  
Mass Scaling ◽  
Cluster Mass

Abstract We test two methods, including one that is newly proposed in this work, for correcting for the effects of chameleon f(R) gravity on the scaling relations between the galaxy cluster mass and four observable proxies. Using the first suite of cosmological simulations that simultaneously incorporate both full physics of galaxy formation and Hu-Sawicki f(R) gravity, we find that these rescaling methods work with a very high accuracy for the gas temperature, the Compton Y-parameter of the Sunyaev-Zel’dovich (SZ) effect and the X-ray analogue of the Y-parameter. This allows the scaling relations in f(R) gravity to be mapped to their ΛCDM counterparts to within a few percent. We confirm that a simple analytical tanh formula for the ratio between the dynamical and true masses of haloes in chameleon f(R) gravity, proposed and calibrated using dark-matter-only simulations in a previous work, works equally well for haloes identified in simulations with two very different – full-physics and non-radiative – baryonic models. The mappings of scaling relations can be computed using this tanh formula, which depends on the halo mass, redshift and size of the background scalar field, also at a very good accuracy. Our results can be used for accurate determination of the cluster mass using SZ and X-ray observables, and will form part of a general framework for unbiased and self-consistent tests of gravity using data from present and upcoming galaxy cluster surveys. We also propose an alternative test of gravity, using the YX-temperature relation, which does not involve mass calibration.

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 host galaxies of 106 rapidly evolving transients discovered by the Dark Energy Survey

2020 ◽  
Vol 498 (2) ◽  
pp. 2575-2593 ◽  
Author(s):  
P Wiseman ◽  
M Pursiainen ◽  
M Childress ◽  
E Swann ◽  
M Smith ◽  
...  
Keyword(s):  
Dark Energy ◽  
Gamma Ray ◽  
Fast Time ◽  
Host Galaxies ◽  
Star Forming ◽  
Chemical Enrichment ◽  
Dark Energy Survey ◽  
Explosion Emission ◽  
Stellar Masses ◽  
Energy Survey

ABSTRACT Rapidly evolving transients (RETs), also termed fast blue optical transients, are a recently discovered group of astrophysical events that display rapid luminosity evolution. RETs typically rise to peak in less than 10 d and fade within 30, a time-scale unlikely to be compatible with the decay of Nickel-56 that drives conventional supernovae (SNe). Their peak luminosity spans a range of −15 < Mg < −22.5, with some events observed at redshifts greater than 1. Their evolution on fast time-scales has hindered high-quality follow-up observations, and thus their origin and explosion/emission mechanism remains unexplained. In this paper, we present the largest sample of RETs to date, comprising 106 objects discovered by the Dark Energy Survey, and perform the most comprehensive analysis of RET host galaxies. Using deep-stacked photometry and emission lines from OzDES spectroscopy, we derive stellar masses and star formation rates (SFRs) for 49 host galaxies, and metallicities ([O/H]) for 37. We find that RETs explode exclusively in star-forming galaxies and are thus likely associated with massive stars. Comparing RET hosts to samples of host galaxies of other explosive transients as well as field galaxies, we find that RETs prefer galaxies with high specific SFRs (〈log (sSFR)〉 ∼ −9.6), indicating a link to young stellar populations, similar to stripped-envelope SNe. RET hosts appear to show a lack of chemical enrichment, their metallicities akin to long-duration gamma-ray bursts and superluminous SN host galaxies (〈12 + log (O/H)〉 ∼ 9.4). There are no clear relationships between mass or SFR of the host galaxies and the peak magnitudes or decline rates of the transients themselves.

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