An accurate reconstruction of galaxy cluster masses is key to use this population of objects as a cosmological probe. In this work we present a study on the hydrostatic-to-lensing mass scaling ...relation for a sample of 53 clusters whose masses were reconstructed homogeneously in a redshift range between z = 0.05 and 1.07. The M 500 mass for each cluster was indeed inferred from the mass profiles extracted from the X-ray and lensing data, without using a priori observable-mass scaling relations. We assessed the systematic dispersion of the masses estimated with our reference analyses with respect to other published mass estimates. Accounting for this systematic scatter does not change our main results, but enables the propagation of the uncertainties related to the mass reconstruction method or used dataset. Our analysis gives a hydrostatic-to-lensing mass bias of (1− b ) = 0.739 −0.070 +0.075 and no evidence of evolution with redshift. These results are robust against possible subsample differences.
The “Cluster HEritage project with XMM-Newton : Mass Assembly and Thermodynamics at the End point of structure formation” (CHEX-MATE) is a multi-year heritage program to obtain homogeneous XMM-Newton ...observations of a representative sample of 118 galaxy clusters. The observations are tuned to reconstruct the distribution of the main thermodynamic quantities of the intra-cluster medium up to R 500 and to obtain individual mass measurements, via the hydrostatic-equilibrium equation, with a precision of 15−20%. Temperature profiles are a necessary ingredient for the scientific goals of the project and it is thus crucial to derive the best possible temperature measurements from our data. This is why we have built a new pipeline for spectral extraction and analysis of XMM-Newton data, based on a new physically motivated background model and on a Bayesian approach with Markov chain Monte Carlo methods, which we present in this paper for the first time. We applied this new method to a subset of 30 galaxy clusters representative of the CHEX-MATE sample and show that we can obtain reliable temperature measurements up to regions where the source intensity is as low as 20% of the background, keeping systematic errors below 10%. We compare the median profile of our sample and the best-fit slope at large radii with literature results and we find a good agreement with other measurements based on XMM-Newton data. Conversely, when we exclude the most contaminated regions, where the source intensity is below 20% of the background, we find significantly flatter profiles, in agreement with predictions from numerical simulations and independent measurements with a combination of Sunyaev–Zeldovich and X-ray imaging data.
We study the substructure statistics of a representative sample of galaxy clusters by means of two currently popular substructure characterisation methods, power ratios and centroid shifts. We use ...the 31 clusters from the REXCESS sample, compiled from the southern ROSAT All-Sky cluster survey (REFLEX) with a morphologically unbiased selection in X-ray luminosity and redshift, all of which have been reobserved with XMM-Newton. The main goals of this work are to study the relationship between cluster morphology and other bulk properties, and the comparison of the morphology statistics between observations and numerical simulations. We investigate the uncertainties of the substructure parameters via newly-developed Monte Carlo methods, and examine the dependence of the results on projection effects (via the viewing angle of simulated clusters), finding that the uncertainties of the parameters can be quite substantial. Thus while the quantification of the dynamical state of individual clusters with these parameters should be treated with extreme caution, these substructure measures provide powerful statistical tools to characterise trends of properties in large cluster samples. The centre shift parameter, w, is found to be more sensitive in general and offers a larger dynamic range than the power ratios. For the REXCESS sample neither the occurence of substructure nor the presence of cool cores depends on cluster mass; however a weak correlation with X-ray luminosity is present, which is interpreted as selection effect. There is a significant anti-correlation between the existence of substantial substructure and cool cores. The simulated clusters show on average larger substructure parameters than the observed clusters, a trend that is traced to the fact that cool regions are more pronounced in the simulated clusters, leading to stronger substructure measures in merging clusters and clusters with offset cores. Moreover, the frequency of cool regions is higher in the simulations than in the observations, implying that the description of the physical processes shaping cluster formation in the simulations requires further improvement.
Context.A study of the structural and scaling properties of the temperature distribution of the hot, X-ray emitting intra-cluster medium of galaxy clusters, and its dependence on dynamical state, can ...give insights into the physical processes governing the formation and evolution of structure. Aims.Accurate temperature measurements are a pre-requisite for a precise knowledge of the thermodynamic properties of the intra-cluster medium. Methods.We analyse the X-ray temperature profiles from XMM-Newton observations of 15 nearby ($z<0.2$) clusters, drawn from a statistically representative sample. The clusters cover a temperature range from 2.5 keV to 8.5 keV, and present a variety of X-ray morphologies. We derive accurate projected temperature profiles to ~$ 0.5\,R_{200}$, and compare structural properties (outer slope, presence of cooling core) with a quantitative measure of the X-ray morphology as expressed by power ratios. We also compare the results to recent cosmological numerical simulations. Results.Once the temperature profiles are scaled by an average cluster temperature (excluding the central region) and the estimated virial radius, the profiles generally decline in the region $0.1\,R_{200} \la R \la 0.5\,R_{200}$. The central regions show the largest scatter, attributable mostly to the presence of cool core clusters. There is good agreement with numerical simulations outside the core regions. We find no obvious correlations between power ratio and outer profile slope. There may however be a weak trend with the existence of a cool core, in the sense that clusters with a central temperature decrement appear to be slightly more regular. Conclusions.The present results lend further evidence to indicate that clusters are a regular population, at least outside the core region.
Bevacizumab has broad anti-tumour activity, but substantial risk of hypertension. No reliable markers are available for predicting bevacizumab-induced hypertension.
A genome-wide association study ...(GWAS) was performed in the phase III bevacizumab-based adjuvant breast cancer trial, ECOG-5103, to evaluate for an association between genotypes and hypertension. GWAS was conducted in those who had experienced systolic blood pressure (SBP) >160 mm Hg during therapy using binary analysis and a cumulative dose model for the total exposure of bevacizumab. Common toxicity criteria (CTC) grade 3-5 hypertension was also assessed. Candidate SNP validation was performed in the randomised phase III trial, ECOG-2100.
When using the phenotype of SBP>160 mm Hg, the most significant association in SV2C (rs6453204) approached and met genome-wide significance in the binary model (P=6.0 × 10(-8); OR=3.3) and in the cumulative dose model (P=4.7 × 10(-8); HR=2.2), respectively. Similar associations with rs6453204 were seen for CTC grade 3-5 hypertension but did not meet genome-wide significance. Validation study from ECOG-2100 demonstrated a statistically significant association between this SNP and grade 3/4 hypertension using the binary model (P-value=0.037; OR=2.4).
A genetic variant in SV2C predicted clinically relevant bevacizumab-induced hypertension in two independent, randomised phase III trials.
Temperature profiles of the hot galaxy cluster intracluster medium (ICM) have a complex non-linear structure that traditional parametric modelling may fail to fully approximate. For this study, we ...made use of neural networks, for the first time, to construct a data-driven non-parametric model of ICM temperature profiles. A new deconvolution algorithm was then introduced to uncover the true (3D) temperature profiles from the observed projected (2D) temperature profiles. An auto-encoder-inspired neural network was first trained by learning a non-linear interpolatory scheme to build the underlying model of 3D temperature profiles in the radial range of 0.02–2
R
500
, using a sparse set of hydrodynamical simulations from the T
HREE
H
UNDRED
P
ROJECT
. A deconvolution algorithm using a learning-based regularisation scheme was then developed. The model was tested using high and low resolution input temperature profiles, such as those expected from simulations and observations, respectively. We find that the proposed deconvolution and deprojection algorithm is robust with respect to the quality of the data, the morphology of the cluster, and the deprojection scheme used. The algorithm can recover unbiased 3D radial temperature profiles with a precision of around 5% over most of the fitting range. We apply the method to the first sample of temperature profiles obtained with
XMM-Newton
for the CHEX-MATE project and compared it to parametric deprojection and deconvolution techniques. Our work sets the stage for future studies that focus on the deconvolution of the thermal profiles (temperature, density, pressure) of the ICM and the dark matter profiles in galaxy clusters, using deep learning techniques in conjunction with X-ray, Sunyaev Zel’Dovich (SZ) and optical datasets.
We have identified new clusters and characterized previously unknown
Planck
Sunyaev–Zeldovich (SZ) sources from the first
Planck
catalogue of SZ sources (PSZ1). The results presented here correspond ...to an optical follow-up observational programme developed during approximately one year (2014) at Roque de los Muchachos Observatory, using the 2.5 m
Isaac Newton
telescope, the 3.5 m Telescopio Nazionale
Galileo
, the 4.2 m
William Herschel
telescope and the 10.4 m Gran Telescopio Canarias. We have characterized 115 new PSZ1 sources using deep optical imaging and spectroscopy. We adopted robust criteria in order to consolidate the SZ counterparts by analysing the optical richness, the 2D galaxy distribution, and velocity dispersions of clusters. Confirmed counterparts are considered to be validated if they are rich structures, well aligned with the
Planck
PSZ1 coordinate and show relatively high velocity dispersion. Following this classification, we confirm 53 clusters, which means that 46% of this PSZ1 subsample has been validated and characterized with this technique. Sixty-two SZ sources (54% of this PSZ1 subset) remain unconfirmed. In addition, we find that the fraction of unconfirmed clusters close to the galactic plane (at |
b
| < 25°) is greater than that at higher galactic latitudes (|
b
| > 25°), which indicates contamination produced by radio emission of galactic dust and gas clouds on these SZ detections. In fact, in the majority of the cases, we detect important galactic cirrus in the optical images, mainly in the SZ target located at low galactic latitudes, which supports this hypothesis.
The Planck catalogue of SZ sources limits itself to a significance threshold of 4.5 to ensure a low contamination rate by false cluster candidates. This means that only the most massive clusters at ...redshift z> 0.5, and in particular z> 0.7, are expected to enter into the catalogue, with a large number of systems in that redshift regime being expected around and just below that threshold. In this paper, we follow-up a sample of SZ sources from the Planck SZ catalogues from 2013 and 2015. In the latter maps, we consider detections around and at lower significance than the threshold adopted by the Planck Collaboration. To keep the contamination rate low, our 28 candidates are chosen to have significant WISE detections, in combination with non-detections in SDSS/DSS, which effectively selects galaxy cluster candidates at redshifts z ≳ 0.5. By taking r- and z-band imaging with MegaCam at CFHT, we bridge the 4000 Å rest-frame break over a significant redshift range, thus allowing accurate redshift estimates of red-sequence cluster galaxies up to z ~ 0.8. After discussing the possibility that an overdensity of galaxies coincides -by chance- with a Planck SZ detection, we confirm that 16 of the candidates have likely optical counterparts to their SZ signals, 13 (6) of which have an estimated redshift z> 0.5 (z> 0.7). The richnesses of these systems are generally lower than expected given the halo masses estimated from the Planck maps. However, when we follow a simplistic model to correct for Eddington bias in the SZ halo mass proxy, the richnesses are consistent with a reference mass-richness relation established for clusters detected at higher significance. This illustrates the benefit of an optical follow-up, not only to obtain redshift estimates, but also to provide an independent mass proxy that is not based on the same data the clusters are detected with, and thus not subject to Eddington bias.
Abstract
The dense outflow through Denmark Strait is the largest contributor to the lower limb of the Atlantic meridional overturning circulation, yet a description of the full velocity field across ...the strait remains incomplete. Here we analyze a set of 22 shipboard hydrographic–velocity sections occupied along the Látrabjarg transect at the Denmark Strait sill, obtained over the time period 1993–2018. The sections provide the first complete view of the kinematic components at the sill: the shelfbreak East Greenland Current (EGC), the combined flow of the separated EGC, and the North Icelandic Jet (NIJ), and the northward-flowing North Icelandic Irminger Current (NIIC). The total mean transport of overflow water is 3.54 ± 0.29 Sv (1 Sv ≡ 10
6
m
3
s
−1
), comparable to previous estimates. The dense overflow is partitioned in terms of water mass constituents and flow components. The mean transports of the two types of overflow water—Atlantic-origin Overflow Water and Arctic-origin Overflow Water—are comparable in Denmark Strait, while the merged NIJ–separated EGC transports 55% more water than the shelfbreak EGC. A significant degree of water mass exchange takes place between the branches as they converge in Denmark Strait. There are two dominant time-varying configurations of the flow that are characterized as a cyclonic state and a noncyclonic state. These appear to be wind-driven. A potential vorticity analysis indicates that the flow through Denmark Strait is subject to symmetric instability. This occurs at the top of the overflow layer, implying that the mixing/entrainment process that modifies the overflow water begins at the sill.
We present an analysis of the mass and entropy profiles of three poor galaxy clusters (A1991, A2717 and MKW9) observed with XMM-Newton. The clusters have very similar temperatures ($kT= 2.65$, 2.53 ...and 2.58 keV), and similar redshifts ($0.04 \la z \la 0.06$). We trace the surface brightness, temperature, entropy and integrated mass profiles with excellent precision up to ~$500~h_{70}^{-1}$ kpc (A1991 and A2717) and ~$350~h_{70}^{-1}$ kpc (MKW9). This corresponds to $0.5(0.35)~r_{200}$, where r200 is the radius corresponding to a density contrast of 200 with respect to the critical density at the cluster redshifts. None of the surface brightness profiles is well fitted with a single β-model. Double isothermal β-models provide reasonable fits, and in all cases the value of the external β parameter is consistent with the value found for richer clusters. The temperature profiles have central dips but are approximately flat at the exterior, up to the detection limit. The integrated mass profiles are very similar in physical units and are reasonably well fitted with the NFW mass model with concentration parameters in the range $c_{200} =4{-}6$ and $M_{200} = 1.2{-}1.6\times10^{14}~h_{70}^{-1}\,{M_{\odot}}$. A King model is inconsistent with these mass data. The entropy profiles are very similar at large scale, but there is some scatter in the very central region ($r \la 50$ kpc). However, none of the clusters has an isentropic core. We then discuss the structural and scaling properties of cluster mass and entropy profiles, including similar quality data on the slightly cooler cluster A1983 ($kT= 2.2$ keV), and on the massive cluster A1413 ($kT= 6.5$ keV). We find that the mass profiles scaled in units of M200 and r200 nearly coincide, with $\la$20 per cent dispersion in the radial range $0.05{-}0.5~r_{200}$, where we could compare the profiles without excessive extrapolation. We provide a quantitative test of mass profile shapes by combining the concentration parameters of these poor clusters with other values of similar precision from the literature, and comparing with the $c_{200} - M_{200}$ relation derived from numerical simulations for a ΛCDM cosmology. The data are fully consistent with the predictions, taking into account the measurement errors and expected intrinsic scatter, in the mass range $M_{\rm 200}= 1.2 \times10^{14}-1.9 \times10^{15}~h_{70}^{-1}\,{M_{\odot}}$. This excellent agreement with theoretical predictions – a quasi universal cusped mass profile with concentration parameters as expected – shows that the physics of the dark matter collapse is basically understood. Scaling the entropy profiles using the self-similar relation $S \propto T$, we find a typical scatter of ~30 per cent in scaled entropy in the radial range $0.05{-}0.5~r_{200}$. The dispersion is reduced (~22 per cent) if we use the empirical relation $S \propto T^{0.65}$. The scatter is nearly constant with radius, indicating a genuine similarity in entropy profile shape. The averaged scaled profile is well fitted by a power law for $0.05<r/r_{200}< 0.5$, with a slope slightly lower than expected from pure shock heating ($\alpha = 0.94\pm0.14$), and a normalisation at $0.1~r_{200}$ consistent with previous ROSAT/ASCA studies. These precise XMM observations confirm that the entropy profiles of clusters are self-similar down to low mass ($kT\sim2~\rm~keV$), but that the entropy temperature relation is shallower than in the purely gravitational model. This self-similarity of shape is a strong constraint, allowing us to rule out simple pre-heating models. The gas history thus probably depends not only on gravitational processes, but also on the interplay between cooling and various galaxy feedback mechanisms.
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