Mapping of the intra-cluster medium out to the virial radius

In this thesis, I study the thermodynamic properties of the intracluster medium out to the virial radius, making use of a unique combination of dedicated XMM-Newton exposures and Planck maps, thus exploiting the capabilities of multi-wavelength observations, to constrain at an unprecedented level the thermodynamic properties in a complete sample of galaxy clusters. I will explore in detail their self-similar properties, their radial dependence, and their implication. This work provides an important legacy value for any future studies of galaxy cluster until the next generation of X-ray telescopes comes along

The Physics of Galaxy Cluster Outskirts

As the largest virialized structures in the universe, galaxy clusters continue to grow and accrete matter from the cosmic web. Due to the low gas density in the outskirts of clusters, measurements are very challenging, requiring extremely sensitive telescopes across the entire electromagnetic spectrum. Observations using X-rays, the Sunyaev-Zeldovich effect, and weak lensing and galaxy distributions from the optical band, have over the last decade helped to unravel this exciting new frontier of cluster astrophysics, where the infall and virialization of matter takes place. Here, we review the current state of the art in our observational and theoretical understanding of cluster outskirts, and discuss future prospects for exploration using newly planned and proposed observatories.Comment: 56 pages. Review paper. Published in Space Science Review

Toward the low-scatter selection of X-ray clusters : Galaxy cluster detection with eROSITA through cluster outskirts

Context. One key ingredient in using galaxy clusters as a precision cosmological probe in large X-ray surveys is understanding selection effects. The dependence of the X-ray emission on the square of the gas density leads to a predominant role of cool cores in the detection of galaxy clusters. The contribution of cool cores to the X-ray luminosity does not scale with cluster mass and cosmology and therefore affects the use of X-ray clusters in producing cosmological constraints.Aims. One of the main science goals of the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) mission is to constrain cosmology with a wide X-ray survey. We propose an eROSITA galaxy cluster detection scheme that avoids the use of X-ray cluster centers in detection. We calculate theoretical expectations and characterize the performance of this scheme by simulations.Methods. We performed Monte Carlo simulations of the upcoming eROSITA mission, including known foreground and background components. By performing realistic simulations of point sources in survey mode, we searched for spatial scales where the extended signal is not contaminated by the point-source flux. We derive a combination of scales and thresholds, which result in a clean extended source catalog. We designed the output of the cluster detection, which enables calibrating the core-excised luminosity using external mass measurements. We provide a way to incorporate the results of this calibration in producing the final core-excised luminosity.Results. Similarly to other galaxy cluster detection pipelines, we sample the detection space of the flux - cluster core radius of our method and find many similarities with the pipeline used in the 400d survey. Both detection methods require large statistics on compact clusters in order to reduce the contamination from point sources. The benefit of our pipeline consists of the sensitivity to the outer cluster shapes, which are characterized by large core sizes with little cluster to cluster variation at a fixed total mass of the cluster.Conclusions. Galaxy cluster detection through cluster outskirts improves the cluster characterization using eROSITA survey data and is expected to yield well-characterized cluster catalogs with simple selection functions.Peer reviewe

Iron in X-COP: tracing enrichment in cluster outskirts with high accuracy abundance profiles

We present the first metal abundance profiles for a representative sample of massive clusters. Our measures extend to $R_{500}$ and are corrected for a systematic error plaguing previous outskirt estimates. Our profiles flatten out at large radii, admittedly not a new result, however the radial range and representative nature of our sample extends its import well beyond previous findings. We find no evidence of segregation between cool-core and non-cool-core systems beyond $\sim 0.3 R_{500}$, implying that, as was found for thermodynamic properties (Ghirardini et al, 2019), the physical state of the core does not affect global cluster properties. Our mean abundance within $R_{500}$ shows a very modest scatter, $<$15%, suggesting the enrichment process must be quite similar in all these massive systems. This is a new finding and has significant implications on feedback processes. Together with results from thermodynamic properties presented in a previous X-COP paper, it affords a coherent picture where feedback effects do not vary significantly from one system to another. By combing ICM with stellar measurements we have found the amount of Fe diffused in the ICM to be about ten times higher than that locked in stars. Although our estimates suggest, with some strength, that the measured iron mass in clusters is well in excess of the predicted one, systematic errors prevent us from making a definitive statement. Further advancements will only be possible when systematic uncertainties, principally those associated to stellar masses, both within and beyond $R_{500}$, can be reduced.Comment: 23 pages, 23 figures; submitted to A&

Characterization of the Particle-induced Background of XMM-Newton EPIC-pn: Short- and Long-term Variability

The particle-induced background of X-ray observatories is produced by galactic cosmic ray (GCR) primary protons, electrons, and He ions. Events due to direct interaction with the detector are usually removed by onboard processing. The interactions of these primary particles with the detector environment produce secondary particles that mimic X-ray events from celestial sources, and are much more difficult to identify. The filter-wheel closed data from the XMM-Newton EPIC-pn camera in small window mode (SWM) contains both the X-ray-like background events, and the events due to direct interactions with the primary particles. From this data, we demonstrate that X-ray-like background events are spatially correlated with the primary particle interaction. This result can be used to further characterize and reduce the non-X-ray background in silicon-based X-ray detectors in current and future missions. We also show that spectrum and pattern fractions of secondary particle events are different from those produced by cosmic X-rays

The eROSITA view of the Abell 3391/95 field: The Northern Clump. The largest infalling structure in the longest known gas filament observed with eROSITA, XMM-Newton, and Chandra

SRG/eROSITA PV observations revealed the A3391/95 cluster system and the Northern Clump (MCXC J0621.7-5242 galaxy cluster) are aligning along a cosmic filament in soft X-rays, similarly to what has been seen in simulations before. We aim to understand the dynamical state of the Northern Clump as it enters the atmosphere ($3\times R_{200}$) of A3391. We analyzed joint eROSITA, XMM-Newton, and Chandra observations to probe the morphological, thermal, and chemical properties of the Northern Clump from its center out to a radius of 988 kpc ($R_{200}$). We utilized the ASKAP/EMU radio data, DECam optical image, and Planck y-map to study the influence of the WAT radio source on the Northern Clump central ICM. From the Magneticum simulation, we identified an analog of the A3391/95 system along with an infalling group resembling the Northern Clump. The Northern Clump is a WCC cluster centered on a WAT radio galaxy. The gas temperature over $0.2-0.5R_{500}$ is $k_BT_{500}=1.99\pm0.04$ keV. We employed the $M-T$ scaling relation and obtained a mass estimate of $M_{500}=(7.68\pm0.43)\times10^{13}M_{\odot}$ and $R_{500}=(636\pm12)$ kpc. Its atmosphere has a boxy shape and deviates from spherical symmetry. We identify a southern surface brightness edge, likely caused by subsonic motion relative to the filament gas. At $\sim\! R_{500}$, the southern atmosphere appears to be 42% hotter than its northern atmosphere. We detect a downstream tail pointing toward the north with a projected length of $\sim318$ kpc, plausibly the result of ram pressure stripping. The analog group in the Magneticum simulation is experiencing changes in its gas properties and a shift between the position of the halo center and that of the bound gas, while approaching the main cluster pair.Comment: 24 pages, 17 figures (main text), 6 figures (appendix). Submitted to A&A for the Special Issue: The Early Data Release of eROSITA and Mikhail Pavlinsky ART-XC on the SRG Mission. For more information, see https://astro.uni-bonn.de/~averonica/NorthernClump/eROSITA_A3391_Northern_Clump_AIfA.htm

The eROSITA Final Equatorial Depth Survey (eFEDS) X-ray catalogue

Context. The eROSITA X-ray telescope on board the Spectrum-Roentgen-Gamma (SRG) observatory combines a large field of view and a large collecting area in the energy range between similar to 0.2 and similar to 8.0 keV. This gives the telescope the capability to perform uniform scanning observations of large sky areas. Aims. SRG/eROSITA performed scanning observations of the similar to 140 square degree eROSITA Final Equatorial Depth Survey field (the eFEDS field) as part of its performance verification phase ahead of the planned four years of all-sky scanning operations. The observing time of eFEDS was chosen to slightly exceed the depth expected in an equatorial field after the completion of the all-sky survey. While verifying the capability of eROSITA to perform large-area uniform surveys and serving as a test and training dataset to establish calibration and data analysis procedures, the eFEDS survey also constitutes the largest contiguous soft X-ray survey at this depth to date, supporting a range of early eROSITA survey science investigations. Here we (i) present a catalogue of detected X-ray sources in the eFEDS field providing information about source positions and extent, as well as fluxes in multiple energy bands, and (ii) document the suite of tools and procedures developed for eROSITA data processing and analysis, which were validated and optimised by the eFEDS work. Methods. The data were fed through a standard data processing pipeline, which applies X-ray event calibration and provides a set of standard calibrated data products. A multi-stage source detection procedure, building in part on experience from XMM-Newton, was optimised and calibrated by performing realistic simulations of the eROSITA eFEDS observations. Source fluxes were computed in multiple standard energy bands by forced point source fitting and aperture photometry. We cross-matched the eROSITA eFEDS source catalogue with previous XMM-ATLAS observations, which confirmed the excellent agreement of the eROSITA and XMM-ATLAS source fluxes. Astrometric corrections were performed by cross-matching the eROSITA source positions with an optical reference catalogue of quasars. Results. We present a primary catalogue of 27 910 X-ray sources (542 of which are significantly spatially extended) detected in the 0.2-2.3 keV energy range with detection likelihoods >= 6, corresponding to a (point source) flux limit of 6.5 x 10(-15) erg cm(-2 )s(-1) in the 0.5-2.0 keV energy band (80% completeness). A supplementary catalogue contains 4774 low-significance source candidates with detection likelihoods between 5 and 6. In addition, a hard-band sample of 246 sources detected in the energy range 2.3-5.0 keV above a detection likelihood of 10 is provided. In an appendix, we finally describe the dedicated data analysis software package, the eROSITA calibration database, and the standard calibrated data products.Peer reviewe

Guidelines on the diagnosis, treatment and management of visceral and renal arteries aneurysms: a joint assessment by the Italian Societies of Vascular and Endovascular Surgery (SICVE) and Medical and Interventional Radiology (SIRM)

: The objective of these Guidelines is to provide recommendations for the classification, indication, treatment and management of patients suffering from aneurysmal pathology of the visceral and renal arteries. The methodology applied was the GRADE-SIGN version, and followed the instructions of the AGREE quality of reporting checklist. Clinical questions, structured according to the PICO (Population, Intervention, Comparator, Outcome) model, were formulated, and systematic literature reviews were carried out according to them. Selected articles were evaluated through specific methodological checklists. Considered Judgments were compiled for each clinical question in which the characteristics of the body of available evidence were evaluated in order to establish recommendations. Overall, 79 clinical practice recommendations were proposed. Indications for treatment and therapeutic options were discussed for each arterial district, as well as follow-up and medical management, in both candidate patients for conservative therapy and patients who underwent treatment. The recommendations provided by these guidelines simplify and improve decision-making processes and diagnostic-therapeutic pathways of patients with visceral and renal arteries aneurysms. Their widespread use is recommended

Evolution of the Thermodynamic Properties of Clusters of Galaxies out to Redshift of 1.8

Abstract The thermodynamic properties of the hot plasma in galaxy clusters retain information on the processes leading to the formation and evolution of the gas in their deep, dark matter potential wells. These processes are dictated not only by gravity but also by gas physics, e.g., active galactic nucleus feedback and turbulence. In this work, we study the thermodynamic properties, e.g., density, temperature, pressure, and entropy, of the most massive and the most distant (seven clusters at z &gt; 1.2) clusters selected by the South Pole Telescope and compare them with those of the nearby clusters (13 clusters at z &lt; 0.1) to constrain their evolution as a function of time and radius. We find that thermodynamic properties in the outskirts of high-redshift clusters are remarkably similar to the low-redshift clusters, and their evolution follows the prediction of the self-similar model. Their intrinsic scatter is larger, indicating that the physical properties that lead to the formation and virialization of cluster outskirts show evolving variance. On the other hand, thermodynamic properties in the cluster cores deviate significantly from self-similarity, indicating that the processes that regulate the core are already in place in these very high redshift clusters. This result is supported by the unevolving physical scatter of all thermodynamic quantities in cluster cores.</jats:p