Search

We present an extension to a Sunyaev–Zel'dovich Effect (SZE) selected cluster catalogue based on observations from the South Pole Telescope (SPT); this catalogue extends to lower signal to noise than the previous SPT–SZ catalogue and therefore includes lower mass clusters. Optically derived redshifts, centres, richnesses, and morphological parameters together with catalogue contamination and completeness statistics are extracted using the multicomponent matched filter (MCMF) algorithm applied to the S/N > 4 SPT–SZ candidate list and the Dark Energy Survey (DES) photometric galaxy catalogue. The main catalogue contains 811 sources above S/N = 4, has 91  per cent purity, and is 95 per cent complete with respect to the original SZE selection. It contains in total 50 per cent more clusters and twice as many clusters above z  = 0.8 in comparison to the original SPT-SZ sample. The MCMF algorithm allows us to define subsamples of the desired purity with traceable impact on catalogue completeness. As an example, we provide two subsamples with S/N > 4.25 and S/N > 4.5 for which the sample contamination and cleaning-induced incompleteness are both as low as the expected Poisson noise for samples of their size. The subsample with S/N > 4.5 has 98 per cent purity and 96 per cent completeness and is part of our new combined SPT cluster and DES weak-lensing cosmological analysis. We measure the number of false detections in the SPT-SZ candidate list as function of S/N, finding that it follows that expected from assuming Gaussian noise, but with a lower amplitude compared to previous estimates from simulations. [ABSTRACT FROM AUTHOR]

Aims. Characterising galaxy cluster populations from a catalogue of sources selected in astronomical surveys requires knowledge of sample incompleteness, known as the selection function. The first All-Sky Survey (eRASS1) by eROSITA on board Spectrum Roentgen Gamma (SRG) has enabled the collection of large samples of galaxy clusters detected in the soft X-ray band over the western Galactic hemisphere. The driving goal consists in constraining cosmological parameters, which puts stringent requirements on the accuracy and flexibility of explainable selection function models. Methods. We used a large set of mock observations of the eRASS1 survey and we processed simulated data identically to the real eRASS1 events. We matched detected sources to simulated clusters and we associated detections to intrinsic cluster properties. We trained a series of models to build selection functions depending only on observable surface brightness data. We developed a second series of models relying on global cluster characteristics such as X-ray luminosity, flux, and the expected instrumental count rate as well as on morphological properties. We validated our models using our simulations and we ranked them according to selected performance metrics. We validated the models with datasets of clusters detected in X-rays and via the Sunyaev–Zeldovich effect. We present the complete Bayesian population modelling framework developed for this purpose. Results. Our results reveal the surface brightness characteristics most relevant to cluster selection in the eRASS1 sample, in particular the ambiguous role of central surface brightness at the scale of the instrument resolution. We have produced a series of user-friendly selection function models and demonstrated their validity and their limitations. Our selection function for bright sources reproduces the catalogue matches with external datasets well. We discuss potential inconsistencies in the selection models at a low signal-to-noise revealed by comparison with a deep X-ray sample acquired by eROSITA during its performance verification phase. Conclusions. Detailed modelling of the eRASS1 galaxy cluster selection function is made possible by reformulating selection into a classification problem. Our models are used in the first eRASS1 cosmological analysis and in sample studies of eRASS1 cluster and groups. These models are crucial for science with eROSITA cluster samples and our new methods pave the way for further investigation of faint cluster selection effects. [ABSTRACT FROM AUTHOR]

Context. Number counts of galaxy clusters across redshift are a powerful cosmological probe if a precise and accurate reconstruction of the underlying mass distribution is performed – a challenge called mass calibration. With the advent of wide and deep photometric surveys, weak gravitational lensing (WL) by clusters has become the method of choice for this measurement. Aims. We measured and validated the WL signature in the shape of galaxies observed in the first three years of the Dark Energy Survey (DES Y3) caused by galaxy clusters and groups selected in the first all-sky survey performed by SRG (Spectrum Roentgen Gamma)/eROSITA (eRASS1). These data were then used to determine the scaling between the X-ray photon count rate of the clusters and their halo mass and redshift. Methods. We empirically determined the degree of cluster member contamination in our background source sample. The individual cluster shear profiles were then analyzed with a Bayesian population model that self-consistently accounts for the lens sample selection and contamination and includes marginalization over a host of instrumental and astrophysical systematics. To quantify the accuracy of the mass extraction of that model, we performed mass measurements on mock cluster catalogs with realistic synthetic shear profiles. This allowed us to establish that hydrodynamical modeling uncertainties at low lens redshifts (z < 0.6) are the dominant systematic limitation. At high lens redshift, the uncertainties of the sources' photometric redshift calibration dominate. Results. With regard to the X-ray count rate to halo mass relation, we determined its amplitude, its mass trend, the redshift evolution of the mass trend, the deviation from self-similar redshift evolution, and the intrinsic scatter around this relation. Conclusions. The mass calibration analysis performed here sets the stage for a joint analysis with the number counts of eRASS1 clusters to constrain a host of cosmological parameters. We demonstrate that WL mass calibration of galaxy clusters can be performed successfully with source galaxies whose calibration was performed primarily for cosmic shear experiments, opening the way for the cluster cosmological exploitation of future optical and NIR surveys like Euclid and LSST. [ABSTRACT FROM AUTHOR]

Odd radio circles (ORCs) are a newly discovered class of extended faint radio sources of unknown origin. We report the first detection of diffuse X-ray gas at the location of a low-redshift ORC (z = 0.046) known as Cloverleaf ORC. This observation was performed with the XMM-Newton X-ray telescope. The physical extent of the diffuse X-ray emission corresponds to a region of approximately 230 kpc by 160 kpc, lying perpendicular to the radio emission detected by ASKAP. The X-ray spectrum shows characteristics of thermal multiphase gas with temperatures of 1.10 ± 0.08 keV and 0.22 ± 0.01 keV and a central density of (4.9 ± 0.6)×10−4 cm−3, indicating that the Cloverleaf ORC resides in a low-mass galaxy group. Using X-ray observations, with hydrostatic equilibrium and isothermal assumptions, we measure the galaxy group to have a gas mass and a total mass of (7.7 ± 0.8)×1011 M⊙ and 2.6 ± 0.3 × 1013 M⊙ within the overdensity radius R500. The presence of a high-velocity subgroup identified in optical data, the orientation of the brightest cluster galaxy, the disturbed morphologies of galaxies toward the east of the Cloverleaf ORC, and the irregular morphology of the X-ray emission suggest that this system is undergoing a galaxy group merger. The radio power of the ORC could be explained by the shock reacceleration of fossil cosmic rays generated by a previous episode of black hole activity in the central active galactic nucleus. [ABSTRACT FROM AUTHOR]

Clusters of galaxies can be used as powerful probes to study astrophysical processes on large scales, test theories of the growth of structure, and constrain cosmological models. The driving science goal of the SRG/eROSITA All-Sky Survey is to assemble a large sample of X-ray clusters with a well-defined selection function to determine the evolution of the mass function and, hence, the cosmological parameters. We present here a catalog of 12 247 optically confirmed galaxy groups and clusters detected in the 0.2–2.3 keV as extended X-ray sources in a 13 116 deg2 region in the western Galactic half of the sky, which eROSITA surveyed in its first six months of operation. The clusters in the sample span the redshift range 0.003 < z < 1.32. The majority (68%) of these clusters, 8361 sources, represent new discoveries without known counterparts in the literature. The mass range of the sample covers three orders of magnitude from 5 × 1012Msun to 2 × 1015Msun. We construct a sample for cosmology with a higher purity level (~95%) than the primary sample, comprising 5259 securely detected and confirmed clusters in the 12791 deg2 common footprint of eRASS1 and the DESI Legacy Survey DR10. We characterize the X-ray properties of each cluster, including their flux, luminosity and temperature, the total mass, gas mass, gas mass fraction, and mass proxy YX. These are determined within two apertures, 300 kpc, and the overdensity radius R500, and are calculated by applying a forward modeling approach with a rigorous X-ray background treatment, K-factor, and the Galactic absorption corrections. Population studies utilizing log N-log S, the number of clusters detected above a given flux limit, and the luminosity function show overall agreement with the previous X-ray surveys after accounting for the survey completeness and purity through the selection function. The first eROSITA All-Sky Survey provides an unprecedented sample of galaxy groups and clusters selected in the X-ray band. The eRASS1 cluster catalog demonstrates the excellent performance of eROSITA for extended source detection, consistent with the pre-launch expectations for the final all-sky survey, eRASS:8. [ABSTRACT FROM AUTHOR]

The eROSITA telescope array aboard the Spektrum Roentgen Gamma (SRG) satellite began surveying the sky in December 2019, with the aim of producing all-sky X-ray source lists and sky maps of an unprecedented depth. Here we present catalogues of both point-like and extended sources using the data acquired in the first six months of survey operations (eRASS1; completed June 2020) over the half sky whose proprietary data rights lie with the German eROSITA Consortium. We describe the observation process, the data analysis pipelines, and the characteristics of the X-ray sources. With nearly 930 000 entries detected in the most sensitive 0.2–2.3 keV energy range, the eRASS1 main catalogue presented here increases the number of known X-ray sources in the published literature by more than 60%, and provides a comprehensive inventory of all classes of X-ray celestial objects, covering a wide range of physical processes. A smaller catalogue of 5466 sources detected in the less sensitive but harder 2.3–5 keV band is the result of the first true imaging survey of the entire sky above 2 keV. We present methods to identify and flag potential spurious sources in the catalogues, which we applied for this work, and we tested and validated the astrometric accuracy via cross-comparison with other X-ray and multi-wavelength catalogues. We show that the number counts of X-ray sources in eRASSl are consistent with those derived over narrower fields by past X-ray surveys of a similar depth, and we explore the number counts variation as a function of the location in the sky. Adopting a uniform all-sky flux limit (at 50% completeness) of F05–2 keV > 5 × 10−14 erg s−1 cm−2, we estimate that the eROSITA all-sky survey resolves into individual sources about 20% of the cosmic X-ray background in the 1–2 keV range. The catalogues presented here form part of the first data release (DR1) of the SRG/eROSITA all-sky survey. Beyond the X-ray catalogues, DR1 contains all detected and calibrated event files, source products (light curves and spectra), and all-sky maps. Illustrative examples of these are provided. [ABSTRACT FROM AUTHOR]

The paper presents the analysis of optically selected GAMA groups and clusters in the SRG/eROSITA X-ray map of eROSITA Final Equatorial Depth Survey, in the halo mass range 1013−5 × 1014 M⊙ and at z < 0.2. All X-ray detections have a clear GAMA counterpart, but most of the GAMA groups in the halo mass range 1013−1014 M⊙ remain undetected. We compare the X-ray surface brightness profiles of the eROSITA detected groups with the mean stacked profile of the undetected low-mass haloes at fixed halo mass. Overall, we find that the undetected groups exhibit less concentrated X-ray surface brightness, dark matter, and galaxy distributions with respect to the X-ray-detected haloes. The mean gas mass fraction profiles are consistent in the two samples within 1.5σ, indicating that the gas follows the dark matter profile. The low-mass concentration and the magnitude gap indicate that these systems are young. They reside with a higher probability in filaments while X-ray-detected groups favour the nodes of the Cosmic Web. Because of the lower central emission, the undetected systems tend to be X-ray underluminous at fixed halo mass and to lie below the LX − M halo relation. Interestingly, the X-ray-detected systems inhabiting the nodes scatter the less around the relation, while those in filaments tend to lie below it. We do not observe any strong relationship between the system X-ray appearance and the active galactic nucleus (AGN) activity. We cannot exclude the role of the past AGN feedback in affecting the gas distribution over the halo lifetime. However, the data suggests that the observed differences might be related to the halo assembly bias. [ABSTRACT FROM AUTHOR]

Contact. The extended ROentgen Survey with an Imaging Telescope Array (eROSITA) telescope on board the Spectrum-Roentgen-Gamma (SRG) mission has completed the first eROSITA All-Sky Survey (eRASS:1). It detected ∼104 galaxy clusters in the western Galactic hemisphere. In the radio band, the Australian Square Kilometre Array Pathfinder (ASKAP) telescope completed its pilot 1 phase of the project Evolutionary Map of the Universe (EMU) with 220 000 sources in a 270 deg2 field overlapping with eRASS:1. These two surveys are used to study radio-mode active galactic nuclei in clusters. Aims. In order to understand the efficiency of radio-mode feedback at the centers of galaxy clusters, we relate the radio properties of the brightest cluster galaxies to the X-ray properties of the host clusters. Methods. We identified the central radio sources in eRASS:1 clusters or calculated corresponding upper limits on the radio luminosity. Then, we derived relations between the X-ray properties of the clusters and the radio properties of the corresponding central radio source. Results. In total, we investigated a sample of 75 clusters. We find a statistically significant correlation between the X-ray luminosity of the cluster and the 944 MHz radio luminosity of the corresponding central radio galaxy. There is also a positive trend between the radio power and the largest linear size of the radio source. The density and the largest linear size are not correlated. We find that the kinetic luminosity of the radio jets in high-luminosity clusters with LX > 1043 erg s−1 is no longer correlated with the X-ray luminosity, and we discuss various reasons. We find an anticorrelation between the central cooling time tcool and the radio luminosity LR, indicating a need for more powerful active galactic nuclei in clusters with short central cooling times. [ABSTRACT FROM AUTHOR]

Context. The characterization of the dynamical state of galaxy clusters is key to studying their evolution, evaluating their selection, and using them as a cosmological probe. In this context, the offsets between different definitions of the center have been used to estimate the cluster disturbance. Aims. Our goal is to study the distribution of the offset between the X-ray and optical centers in clusters of galaxies. We study the offset for clusters detected by the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) on board the Spectrum-Roentgen-Gamma (SRG) observatory. We aim to connect observations to predictions by hydrodynamical simulations and N-body models. We assess the astrophysical effects affecting the displacements. Methods. We measured the offset for clusters observed in the eROSITA Final Equatorial-Depth Survey (eFEDS) and the first eROSITA all-sky survey (eRASS1). We focus on a subsample of 87 massive eFEDS clusters at low redshift, with M500c > 1×1014 M⊙ and 0.15 < z < 0.4. We compared the displacements in such sample to those predicted by the TNG and the Magneticum simulations. We additionally link the observations to the offset parameter Xoff measured for dark matter halos in N-body simulations, using the hydrodynamical simulations as a bridge. Results. We find that, on average, the eFEDS clusters show a smaller offset compared to eRASS1 because the latter contains a larger fraction of massive and disturbed structures. We measured an average offset of ΔX−O = 76.3−27.1+30.1 Δ X − O = 76. 3 − 27.1 + 30.1 $ \Delta_\mathrm{X{-}O} = 76.3_{-27.1}^{+30.1} $ kpc, when focusing on the subsample of 87 eFEDS clusters. This is in agreement with the predictions from TNG and Magneticum, and the distribution of Xoff from dark matter only (DMO) simulations. However, the tails of the distributions are different. Using ΔX − O to classify relaxed and disturbed clusters, we measured a relaxed fraction of 31% in the eFEDS subsample. Finally, we found a correlation between the offset measured on hydrodynamical simulations and Xoff measured on their parent dark-matter-only run and we calibrated the relation between them. Conclusions. We conclude that there is good agreement between the offsets measured in eROSITA data and the predictions from simulations. Baryonic effects cause a decrement (increment) in the low (high) offset regime compared to the Xoff distribution from dark matter-only simulations. The offset–Xoff relation provides an accurate prediction of the true Xoff distribution in Magneticum and TNG. It allows for the offsets to be introduced in a cosmological context with a new method in order to marginalize over selection effects related to the cluster dynamical state. [ABSTRACT FROM AUTHOR]

This paper presents a cosmological analysis based on the properties of X-ray selected clusters of galaxies from the CODEX survey which have been spectroscopically followed up within the SPIDERS programme as part of the sixteenth data release (DR16) of SDSS-IV. The cosmological sub-sample contains a total of 691 clusters over an area of 5350 deg2 with newly measured optical properties provided by a reanalysis of the CODEX source catalogue using redMaPPer and the DESI Legacy Imaging Surveys (DR8). Optical richness is used as a proxy for the cluster mass, and the combination of X-ray, optical, and spectroscopic information ensures that only confirmed virialized systems are considered. Clusters are binned in observed redshift, |$\tilde{z} \in \left[0.1, 0.6 \right)$| and optical richness, |$\tilde{\lambda } \in \left[25, 148 \right)$| and the number of clusters in each bin is modelled as a function of cosmological and richness–mass scaling relation parameters. A high-purity sub-sample of 691 clusters is used in the analysis and best-fitting cosmological parameters are found to be |$\Omega _{m_{0}}=0.34^{+0.09}_{-0.05}$| and |$\sigma _8=0.73^{+0.03}_{-0.03}$|⁠. The redshift evolution of the self-calibrated richness–mass relation is poorly constrained due to the systematic uncertainties associated with the X-ray component of the selection function (which assumes a fixed X-ray luminosity–mass relation with h  = 0.7 and |$\Omega _{m_{0}}=0.30$|⁠). Repeating the analysis with the assumption of no redshift evolution is found to improve the consistency between both cosmological and scaling relation parameters with respect to recent galaxy cluster analyses in the literature. [ABSTRACT FROM AUTHOR]

Chemical enrichment of the Universe at all scales is related to stellar winds and explosive supernovae phenomena. Metals produced by stars and later spread throughout the intracluster medium (ICM) at the megaparsec scale become a fossil record of the chemical enrichment of the Universe and of the dynamical and feedback mechanisms determining their circulation. As demonstrated by the results of the soft X-ray spectrometer onboard Hitomi, high-resolution X-ray spectroscopy is the path to differentiating among the models that consider different metal-production mechanisms, predict the outcoming yields, and are a function of the nature, mass, and/or initial metallicity of their stellar progenitor. Transformational results shall be achieved through improvements in the energy resolution and effective area of X-ray observatories, allowing them to detect rarer metals (e.g. Na, Al) and constrain yet-uncertain abundances (e.g. C, Ne, Ca, Ni). The X-ray Integral Field Unit (X-IFU) instrument onboard the next-generation European X-ray observatory Athena is expected to deliver such breakthroughs. Starting from 100 ks of synthetic observations of 12 abundance ratios in the ICM of four simulated clusters, we demonstrate that the X-IFU will be capable of recovering the input chemical enrichment models at both low (z = 0.1) and high (z = 1) redshifts, while statistically excluding more than 99.5% of all the other tested combinations of models. By fixing the enrichment models which provide the best fit to the simulated data, we also show that the X-IFU will constrain the slope of the stellar initial mass function within ∼12%. These constraints will be key ingredients in our understanding of the chemical enrichment of the Universe and its evolution. [ABSTRACT FROM AUTHOR]

We analyze archival Chandra X-ray Observatory observations of Jupiter to search for emission from the Galilean moons. X-ray emission has previously been reported from Io and Europa using a subset of these data. We confirm this detection, and marginally detect X-ray emission from both Ganymede and Callisto as well. The X-ray spectrum of Europa is strongly peaked around the neutral oxygen fluorescence line (525 eV), while Io's has peaks at both oxygen and sulfur (2308 eV) plus a broad continuum between 350 and 5000 eV. Ganymede's spectrum is similar to Io's, but without the sulfur peak. A few events, mostly clustered around the oxygen line, are detected from Callisto. Using measurements by the Galileo mission of the specific intensity of ambient protons and electrons, we model the X-ray spectra and flux of the moons from two processes: particle-induced X-ray emission (PIXE) from the impact of energetic protons and X-ray emission from electron bremsstrahlung. With uncertainties of a factor of a few, the electron bremsstrahlung and PIXE models overestimate the X-ray flux from Europa, preventing us from making a definitive statement about the origin of the X-ray emission. The PIXE model of Io predicts emission lines at O and S similar to those observed, but underestimates their flux by nearly two orders of magnitude. Based on this discrepancy in the PIXE flux, combined with the detected broadband continuum in the spectrum, we conclude that the X-ray emission from Io is due to electron bremsstrahlung. Likewise, because of Ganymede's broad continuum, we tentatively conclude that its X-ray emission is also due to electron bremsstrahlung. Callisto is too faint in the X-rays to draw any conclusion. Obtaining in situ X-ray observations of the moons would provide a direct measurement of their elemental composition. [ABSTRACT FROM AUTHOR]

We study the properties of the Sydney University Molonglo Sky Survey (SUMSS) 843 MHz radio active galactic nuclei (AGNs) population in galaxy clusters from two large catalogues created using the Dark Energy Survey (DES): ∼11 800 optically selected RM-Y3 and ∼1000 X-ray selected MARD-Y3 clusters. We show that cluster radio loud AGNs are highly concentrated around cluster centres to |$z$| ∼ 1. We measure the halo occupation number for cluster radio AGNs above a threshold luminosity, finding that the number of radio AGNs per cluster increases with cluster halo mass as N  ∝ M 1.2 ± 0.1 (N  ∝ M 0.68 ± 0.34) for the RM-Y3 (MARD-Y3) sample. Together, these results indicate that radio mode feedback is favoured in more massive galaxy clusters. Using optical counterparts for these sources, we demonstrate weak redshift evolution in the host broad-band colours and the radio luminosity at fixed host galaxy stellar mass. We use the redshift evolution in radio luminosity to break the degeneracy between density and luminosity evolution scenarios in the redshift trend of the radio AGNs luminosity function (LF). The LF exhibits a redshift trend of the form (1 + |$z$|⁠)γ in density and luminosity, respectively, of γD = 3.0 ± 0.4 and γP = 0.21 ± 0.15 in the RM-Y3 sample, and γD = 2.6 ± 0.7 and γP = 0.31 ± 0.15 in MARD-Y3. We discuss the physical drivers of radio mode feedback in cluster AGNs, and we use the cluster radio galaxy LF to estimate the average radio-mode feedback energy as a function of cluster mass and redshift and compare it to the core (<0.1 R 500) X-ray radiative losses for clusters at |$z$| < 1. [ABSTRACT FROM AUTHOR]

Objective: The aim of our study is to determine whether there is a change in the plasma levels of copeptin and there is a relationship among the plasma levels of carboxyhemoglobin (COHb), lactate, and copeptin levels in patients presenting to the emergency department with carbon monoxide (CO) poisoning. Methods: Fifty-seven patients admitted to the emergency department with CO poisoning were included in the study. The blood samples of the patients were collected on arrival 0th, 6th, and 12th hours for copeptin, lactate, and COHb levels. Data were analyzed using SPSS-17 statistical software. Results: Arrival serum copeptin levels of the patients were compared to copeptin levels of healthy individuals and a statistically significant difference was found between them (p = 0.008). There was a statistically significant difference between the arrival levels of copeptin and 6th-hour (p = 0.006) and 12th-hour (p = 0.001) levels of copeptin. There was no significant difference between 6th-hour and 12th-hour copeptin levels (p = 0.51). In terms of serum lactate levels, there was a significant difference between arrival and 6th h (p < 0.001), arrival and 12th h (p < 0.001), and 6th and 12th h (p < 0.001). Likewise, in terms of serum COHb levels, there was a significant difference between arrival and 6th h (p < 0.001), arrival and 12th h (p < 0.001), and 6th and 12th h (p < 0.001). There was a positive correlation between COHb and lactate levels on arrival (r = 0.52; p = 0.001). Conclusion: Copeptin as a stress hormone can be used in the diagnosis and monitoring of patients with CO poisoning. However, the copeptin level was not superior to COHb and lactate levels. [ABSTRACT FROM AUTHOR]

Uncertainty in mass–observable scaling relations is currently the limiting factor for galaxy-cluster-based cosmology. Weak gravitational lensing can provide direct mass calibration and reduce the mass uncertainty. We present new ground-based weak lensing observations of 19 South Pole Telescope (SPT) selected clusters at redshifts 0.29 ≤  |$z$|  ≤ 0.61 and combine them with previously reported space-based observations of 13 galaxy clusters at redshifts 0.576 ≤  |$z$|  ≤ 1.132 to constrain the cluster mass scaling relations with the Sunyaev–Zel'dovich effect (SZE), the cluster gas mass M gas and Y X, the product of M gas and X-ray temperature. We extend a previously used framework for the analysis of scaling relations and cosmological constraints obtained from SPT-selected clusters to make use of weak lensing information. We introduce a new approach to estimate the effective average redshift distribution of background galaxies and quantify a number of systematic errors affecting the weak lensing modelling. These errors include a calibration of the bias incurred by fitting a Navarro–Frenk–White profile to the reduced shear using N -body simulations. We blind the analysis to avoid confirmation bias. We are able to limit the systematic uncertainties to 5.6% in cluster mass (68% confidence). Our constraints on the mass–X-ray observable scaling relation parameters are consistent with those obtained by earlier studies and our constraints for the mass–SZE scaling relation are consistent with the simulation-based prior used in the most recent SPT–SZ cosmology analysis. We can now replace the external mass calibration priors used in previous SPT–SZ cosmology studies with a direct, internal calibration obtained for the same clusters. [ABSTRACT FROM AUTHOR]

High-resolution spectroscopy of the core of the Perseus Cluster of galaxies, using the Hitomi satellite above 2 keV and the XMM–Newton Reflection Grating Spectrometer at lower energies, provides reliable constraints on the abundances of O, Ne, Mg, Si, S, Ar, Ca, Cr, Mn, Fe, and Ni. Accounting for all known systematic uncertainties, the Ar/Fe, Ca/Fe, and Ni/Fe ratios are determined with a remarkable precision of less than 10 per cent, while the constraints on Si/Fe, S/Fe, and Cr/Fe are at the 15 per cent level, and Mn/Fe is measured with a 20 per cent uncertainty. The average biases in determining the chemical composition using archival CCD spectra from XMM–Newton and Suzaku typically range from 15 to 40 per cent. A simple model in which the enrichment pattern in the Perseus Cluster core and the protosolar nebula are identical gives a surprisingly good description of the high-resolution X-ray spectroscopy results, with χ2 = 10.7 for 10 degrees of freedom. However, this pattern is challenging to reproduce with linear combinations of existing supernova nucleosynthesis calculations, particularly given the precise measurements of intermediate α-elements enabled by Hitomi. We discuss in detail the degeneracies between various supernova progenitor models and explosion mechanisms, and the remaining uncertainties in these theoretical models. We suggest that including neutrino physics in the core-collapse supernova yield calculations may improve the agreement with the observed pattern of α-elements in the Perseus Cluster core. Our results provide a complementary benchmark for testing future nucleosynthesis calculations required to understand the origin of chemical elements. [ABSTRACT FROM AUTHOR]

We present the first results from a galaxy population study in the highest redshift galaxy clusters identified in the 2500 deg2 South Pole Telescope Sunyaev Zel'dovich effect (SPT-SZ) survey, which is sensitive to M500 ≳ 3 × 1014 M⊙ clusters from z ∼ 0.2 out to the highest redshifts where such massive structures exist. The cluster selection is to first order independent of galaxy properties, making the SPT-SZ sample particularly well suited for cluster galaxy population studies. We carried out a four-band imaging campaign with the Hubble and Spitzer Space Telescopes of the five z ≳ 1.4, S/NSZE >  5 clusters, that are among the rarest most massive clusters known at this redshift. All five clusters show clear overdensities of red galaxies whose colors agree with the initial cluster redshift estimates, although one (SPT-CLJ0607–4448) shows a galaxy concentration much less prominent than the others. The highest redshift cluster in this sample, SPT-CLJ0459–4947 at z ∼ 1.72, is the most distant M500 >  1014 M⊙ cluster discovered thus far through its intracluster medium, and is one of only three known clusters in this mass range at z ≳ 1.7, regardless of selection. Based on UVJ-like photometric classification of quiescent and star-forming galaxies, we find that the quiescent fraction in the cluster central regions (r/r500 <  0.7) is higher than in the field at the same redshift, with corresponding environmental quenching efficiencies typically in the range ∼0.5 − 0.8 for stellar masses log(M/M⊙) > 10.85. We have explored the impact of emission from star formation on the selection of this sample, concluding that all five clusters studied here would still have been detected with S/NSZE> 5, even if they had the same quiescent fraction as measured in the field. Our results thus point towards an efficient suppression of star formation in the central regions of the most massive clusters, occurring already earlier than z ∼ 1.5. [ABSTRACT FROM AUTHOR]

The galaxy phase-space distribution in galaxy clusters provides insights into the formation and evolution of cluster galaxies, and it can also be used to measure cluster mass profiles. We present a dynamical study based on ∼3000 passive, non-emission-line cluster galaxies drawn from 110 galaxy clusters. The galaxy clusters were selected using the Sunyaev–Zel'dovich effect (SZE) in the 2500 deg2 South Pole Telescope (SPT)–SZ survey and cover the redshift range 0.2 < |$z$| < 1.3. We model the clusters using the Jeans equation, while adopting NFW mass profiles and a broad range of velocity dispersion anisotropy profiles. The data prefer velocity dispersion anisotropy profiles that are approximately isotropic near the centre and increasingly radial toward the cluster virial radius, and this is true for all redshifts and masses we study. The pseudo-phase-space density profile of the passive galaxies is consistent with expectations for dark matter particles and subhaloes from cosmological N -body simulations. The dynamical mass constraints are in good agreement with external mass estimates of the SPT cluster sample from either weak lensing, velocity dispersions, or X-ray Y X measurements. However, the dynamical masses are lower (at the 2.2σ level) when compared to the mass calibration favoured when fitting the SPT cluster data to a Λcold dark matter model with external cosmological priors, including cosmic microwave background anisotropy data from Planck. The discrepancy grows with redshift, where in the highest redshift bin the ratio of dynamical to SPT + Planck masses is |$\eta = 0.63^{+0.13}_{-0.08}\pm 0.06$| (statistical and systematic), corresponding to a 2.6σ discrepancy. [ABSTRACT FROM AUTHOR]

Answers to the metal production of the Universe can be found in galaxy clusters, notably within their intra-cluster medium (ICM). The X-ray Integral Field Unit (X-IFU) on board the next-generation European X-ray observatory Athena (2030s) will provide the necessary leap forward in spatially-resolved spectroscopy required to disentangle the intricate mechanisms responsible for this chemical enrichment. In this paper, we investigate the future capabilities of the X-IFU in probing the hot gas within galaxy clusters. From a test sample of four clusters extracted from cosmological hydrodynamical simulations, we present comprehensive synthetic observations of these clusters at different redshifts (up to z ≤ 2) and within the scaled radius R500 performed using the instrument simulator SIXTE. Through 100 ks exposures, we demonstrate that the X-IFU will provide spatially resolved mapping of the ICM physical properties with little to no biases (⪅5%) and well within statistical uncertainties. The detailed study of abundance profiles and abundance ratios within R500 also highlights the power of the X-IFU in providing constraints on the various enrichment models. From synthetic observations out to z = 2, we have also quantified its ability to track the chemical elements across cosmic time with excellent accuracy, and thereby to investigate the evolution of metal production mechanisms as well as the link to the stellar initial mass-function. Our study demonstrates the unprecedented capabilities of the X-IFU of unveiling the properties of the ICM but also stresses the data analysis challenges faced by future high-resolution X-ray missions such as Athena. [ABSTRACT FROM AUTHOR]

Background: The aim of the study was to evaluate the prevalence and morphometric features of mastoid emissary vein (MEV) on multidetector computed tomography (MDCT) scans, emphasize its clinical significance and review its surgical implications.Materials and Methods: Cranial and temporal bone MDCTs of 248 patients (496 sides) were analysed by 2 radiologists. Mastoid foramen (MF) was defined on the 3 dimensional volume rendered (3DVR) images. The MF and mastoid emissary canal (MEC) were investigated in axial thin slices and the diameters of the largest MF and MEC were measured. Mean diameters of MF and MEC were determined. The number of the mastoid foramina was noted. Differences in MF prevalence by sex and side were evaluated.Results: The overall prevalence of MEC was 92.3%. It was observed in 91.5% of women and 93.3% of men. MEC was present on the right side in 84.7% and on the left side in 82.3% of temporal bones. The mean diameter of MF was 1.92 ± ± 1.02 mm on the right and 1.84 ± 0.98 mm on the left. In both sides the number of the MF's changed from absent to triple. The mean diameter of MEC was 1.58 ± 0.86 mm on the right and 1.48 ± 0.79 mm on the left side. The mean diameter of MEC was significantly larger in men. No significant correlation was detected between age and the MEC diameter.Conclusions: The preoperative detection of mastoid emissary veins is necessary. The radiologists should be familiar with their clinical significance and variant appearances and report them accurately. Knowledge of their morphology and surgical implications by the surgeons will make them aware to avoid unexpected and fatal complications while operating in the suboccipital and mastoid area. MDCT is a reliable diagnostic tool for imaging the MEC and MF. [ABSTRACT FROM AUTHOR]

We report our analysis of MACS J0717.5+3745 using 140 and 268 GHz Bolocam data collected at the Caltech Submillimeter Observatory. We detect extended Sunyaev-Zel'dovich (SZ) effect signal at high significance in both Bolocam bands, and we employ Herschel-SPIRE observations to subtract the signal from dusty background galaxies in the 268 GHz data. We constrain the two-band SZ surface brightness toward two of the sub-clusters of MACS J0717.5+3745: the main sub-cluster (named C), and a sub-cluster identified in spectroscopic optical data to have a line-of-sight velocity of +3200 km s–1 (named B). We determine the surface brightness in two separate ways: via fits of parametric models and via direct integration of the images. For both sub-clusters, we find consistent surface brightnesses from both analysis methods. We constrain spectral templates consisting of relativistically corrected thermal and kinetic SZ signals, using a jointly-derived electron temperature from Chandra and XMM-Newton under the assumption that each sub-cluster is isothermal. The data show no evidence for a kinetic SZ signal toward sub-cluster C, but they do indicate a significant kinetic SZ signal toward sub-cluster B. The model-derived surface brightnesses for sub-cluster B yield a best-fit, line-of-sight velocity of vz = +3450 ± 900 km s–1, with (1 – Prob[vz ⩾ 0]) = 1.3 × 10–5 (4.2σ away from 0 for a Gaussian distribution). The directly integrated sub-cluster B SZ surface brightnesses provide a best-fit vz = +2550 ± 1050 km s–1, with (1 – Prob[vz ⩾ 0]) = 2.2 × 10–3 (2.9σ). [ABSTRACT FROM AUTHOR]

We present results from Chandra and XMM-Newton observations of Abell 98 (A98), a galaxy cluster with three major components: a relatively bright subcluster to the north (A98N), a disturbed subcluster to the south (A98S), and a fainter subcluster to the far south (A98SS). We find evidence for surface brightness and temperature asymmetries in A98N consistent with a shock-heated region to the south, which could be created by an early stage merger between A98N and A98S. Deeper observations are required to confirm this result. We also find that A98S has an asymmetric core temperature structure, likely due to a separate ongoing merger. Evidence for this is also seen in optical data. A98S hosts a wide-angle tail radio source powered by a central active galactic nucleus (AGN). We find evidence for a cavity in the intracluster medium that has been evacuated by one of the radio lobes, suggesting that AGN feedback is operating in this system. Examples of cavities in non-cool core clusters are relatively rare. The three subclusters lie along a line in projection, suggesting the presence of a large-scale filament. We observe emission along the filament between A98N and A98S, and a surface brightness profile shows emission consistent with the overlap of the subcluster extended gas halos. We find the temperature of this region is consistent with the temperature of the gas at similar radii outside this bridge region. Lastly, we examine the cluster dynamics using optical data. We conclude A98N and A98S are likely bound to one another with a 67% probability, while A98S and A98SS are not bound at a high level of significance. [ABSTRACT FROM AUTHOR]