Prospects for high-z cluster detections with Planck, based on a follow-up of 28 candidates using MegaCam@CFHT

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 $z\gtrsim0.5$. By taking r- and z-band imaging with MegaCam@CFHT, we bridge the 4000A 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.Comment: 13 pages, 7 figures. Accepted for publication in A&

The Three Hundred : contrasting clusters galaxy density in hydrodynamical and dark matter simulations

Cluster number counts will be a key cosmological probe in the next decade thanks to the Euclid satellite mission. For this purpose, cluster detection algorithm performance, which are sensitive to the spatial distribution of the cluster galaxy members and their luminosity function, need to be accurately characterized. Using The Three Hundred hydrodynamical and dark matter only simulations we study a complete sample of massive clusters beyond 7 (5) $\times$ 10$^{14}$ M$_{\odot}$ at redshift 0 (1) on a $(1.48 \ \mathrm{Gpc})^3$ volume. We find that the mass resolution of the current hydrodynamical simulations (1.5 $\times$ 10$^9$ M$_{\odot}$) is not enough to characterize the luminosity function of the sample in the perspective of Euclid data. Nevertheless, these simulations are still useful to characterize the spatial distribution of the cluster substructures assuming a common relative mass threshold for the different flavours and resolutions. By comparing with the dark matter only version of these simulations, we demonstrate that baryonic physics preserves significantly low mass subhalos (galaxies) as have also been observed in previous studies with less statistics. Furthermore, by comparing the hydro simulations with higher resolution dark matter only simulations of the same objects and taking the same limit in subhalo mass we find significantly more cuspy galaxy density profiles towards the center of the clusters, where the low mass substructures would tend to concentrate. We conclude that using dark matter only simulation may lead to some biases on the spatial distribution and density of galaxy cluster members. Based on the preliminary analysis of few high resolution hydro simulations we conclude that a mass resolution of 1.8 $\times$ 10$^8$ h$^{-1}$ M$_{\odot}$ will be needed for The Three Hundred simulations to approach the expected magnitude limits for the Euclid survey

The 1989 and 2015 outbursts of V404 Cygni: a global study of wind-related optical features

The black hole transient V404 Cygni exhibited a bright outburst in June 2015 that was intensively followed over a wide range of wavelengths. Our team obtained high time resolution optical spectroscopy (~90 s), which included a detailed coverage of the most active phase of the event. We present a database consisting of 651 optical spectra obtained during this event, that we combine with 58 spectra gathered during the fainter December 2015 sequel outburst, as well as with 57 spectra from the 1989 event. We previously reported the discovery of wind-related features (P-Cygni and broad-wing line profiles) during both 2015 outbursts. Here, we build diagnostic diagrams that enable us to study the evolution of typical emission line parameters, such as line fluxes and equivalent widths, and develop a technique to systematically detect outflow signatures. We find that these are present throughout the outburst, even at very low optical fluxes, and that both types of outflow features are observed simultaneously in some spectra, confirming the idea of a common origin. We also show that the nebular phases depict loop patterns in many diagnostic diagrams, while P-Cygni profiles are highly variable on time-scales of minutes. The comparison between the three outbursts reveals that the spectra obtained during June and December 2015 share many similarities, while those from 1989 exhibit narrower emission lines and lower wind terminal velocities. The diagnostic diagrams presented in this work have been produced using standard measurement techniques and thus may be applied to other active low-mass X-ray binaries.Comment: Accepted for publication in MNRAS. 23 pages paper, plus a 9 pages appendix with extra tables and figures. 18 figures are included in the paper and 8 in the appendi

The three hundred project. A machine learning method to infer clusters of galaxy mass radial profiles from mock Sunyaev–Zel’dovich maps

We develop a machine learning algorithm to infer the three-dimensional cumulative radial profiles of total and gas masses in galaxy clusters from thermal Sunyaev–Zel’dovich effect maps. We generate around 73 000 mock images along various lines of sight using 2522 simulated clusters from THE THREE HUNDRED project at redshift z < 0.12 and train a model that combines an auto-encoder and a random forest. Without making any prior assumptions about the hydrostatic equilibrium of the clusters, the model is capable of reconstructing the total mass profile as well as the gas mass profile, which is responsible for the Sunyaev–Zel’dovich effect. We show that the recovered profiles are unbiased with a scatter of about 10 per cent, slightly increasing towards the core and the outskirts of the cluster. We selected clusters in the mass range of 1013.5 ≤ M200/(h−1 M) ≤ 1015.5, spanning different dynamical states, from relaxed to disturbed haloes. We verify that both the accuracy and precision of this method show a slight dependence on the dynamical state, but not on the cluster mass. To further verify the consistency of our model, we fit the inferred total mass profiles with a Navarro–Frenk–White model and contrast the concentration values with those of the true profiles. We note that the inferred profiles are unbiased for higher concentration values, reproducing a trustworthy mass–concentration relation. The comparison with a widely used mass estimation technique, such as hydrostatic equilibrium, demonstrates that our method recovers the total mass that is not biased by non-thermal motions of the gas

Galaxy cluster mass bias from projected mass maps: The Three Hundred-NIKA2 LPSZ twin samples

The determination of the mass of galaxy clusters from observations is subject to systematic uncertainties. Beyond the errors due to instrumental and observational systematic effects, in this work we investigate the bias introduced by modelling assumptions. In particular, we consider the reconstruction of the mass of galaxy clusters from convergence maps employing spherical mass density models. We make use of The Three Hundred simulations, selecting clusters in the same redshift and mass range as the NIKA2 Sunyaev-Zel'dovich Large Program sample: $3 \leq M_{500}/ 10^{14} \mathrm{M}_{\odot} \leq 10$ and $0.5 \leq z \leq 0.9$. We study different modelling and intrinsic uncertainties that should be accounted for when using the single cluster mass estimates for scaling relations. We confirm that the orientation of clusters and the radial ranges considered for the fit have an important impact on the mass bias. The effect of the projection adds uncertainties to the order of $10\%$ to $14\%$ to the mass estimates. We also find that the scatter from cluster to cluster in the mass bias when using spherical mass models is less than $20\%$ of the true mass of the clusters

dolls/puppets like mensch – dolls/puppets as artificial beings. Part 1.2

Die dritte Ausgabe der Zeitschrift denkste: puppe / just a bit of: doll (de:do), ein multi-disziplinäres Online-Journal für Mensch-Puppen-Diskurse, erscheint als Doppelheft, dessen gemeinsamer Themenschwerpunkt lautet: puppen/dolls like mensch – puppen als künstliche meschen. Mit diesem Fokus wird ein Thema aufgegriffen, das Menschen seit der Antike berührt und bis heute ihren Verstand und ihre Imagination, ihre Bedürfnisse und ihre Gefühle in Unruhe versetzt. In Mythologien, literarischen Fiktionen und Narrativen für Erwachsene und Kinder, in Werken der bildenden Künste, im Film, in mechanisch-technischen Anwendungen und Utopien, in den performativen Künsten, in der (Spiel-)Pädagogik und in den verschiedenen Bereichen der Popkultur wirft das Motiv der Puppe mit seinen unterschiedlichsten Ausdrucksformen immer auch existenzielle Fragen auf: Wer und was ist der Mensch? Die Puppe als künstlicher Mensch ist in gewisser Weise wie mensch, ohne Mensch zu sein. Als von Menschen geschaffene Abbilder, Vorbilder, Nachahmungen und Entwürfe des Menschen spiegeln und bestätigen Puppen vorhandene Lebenswelten und loten gleichzeitig Potenziale und Abgründe des Mensch-Seins zwischen Utopie und Dystopie, zwischen Neugier und Hingabe, zwischen Horror und Glückseligkeit, zwischen Macht und Ohnmacht aus. Puppen/dolls like mensch – der doppelte Wortsinn betont die gegebene Ambiguität der Puppen und die spannenden, ihnen innewohnenden Ambivalenzen. Im ersten Teilband (1.1) wird den Spuren und Erscheinungsformen des Puppenmotivs und der Puppe(n) – als literarisches Narrativ, als künstlerisches Motiv, als materialisiertes Objekt – vor allem im Kontext von bildender Kunst, Literatur, Fotografie, Theater und Androidentechnologien nachgegangen. Im zweiten Teilband (1.2) werden zum einen kinderliterarische und (spiel-)didaktische Texte akzentuiert, zum anderen sind hier verschiedene mediale und popkulturelle Formate aus den Bereichen Computerspiel, Comic-Film-Adaptation, Film (unterschiedlicher Genres) und dem Figurentheater versammelt sowie Thematisierungen der Verknüpfung von materiellen Artefakten und literarischen Narrativen. Rezensionen in Form von Essays über literarische Puppen-Narrative, eine Foto-Ausstellung und ein Ballett runden beide Ausgaben ab. Die zeitliche Spanne reicht vom Mittelalter bis in die Gegenwart und Zukunft und zeigt einmal mehr, wie über das Narrativ der Puppe uralte Menschheitsfragen in Traditionslinien eingebunden werden und sie auf faszinierende Weisen fortschreiben.The third edition of the journal denkste: puppe / just a bit of: doll (de: do), a multidisciplinary online journal for human-doll discourses, is a double issue whose shared thematic focus is: puppen/dolls like mensch – dolls/puppets as artificial beings. With this focus, we take up a topic that has concerned mankind since ancient times and has always upset their 'minds' and 'hearts’, their needs and feelings. In mythologies, literary fictions and narratives for adults as well as for children, in works of the visual arts, in film, in mechanical-technical applications and utopias, in the performative arts, in (play-)pedagogy and in the various fields of pop culture, the motif of the doll with its various forms of expression always raises existential questions: Who is man, what is human? The doll as an artificial human being is in a certain way like mensch without being human. As man-made images, as models, imitations and designs of humans, dolls/puppets reflect and confirm existing worlds and at the same time sound out the potentials and abysses of being human between utopia and dystopia, between curiosity and devotion, between horror and bliss, between power and powerlessness. Dolls/puppets like mensch – the double meaning of these words emphasizes the given ambiguity of the dolls/puppets and the intriguing ambivalences inherent in them. In the first part of volume (1.1) the traces and manifestations of the doll motif and of doll(s) – as literary narrative, as artistic motif, as materialized object – will be explored primarily in the context of the fine arts, of literature, photography, theater and android technologies. In the second part of the volume (1.2), on the one hand, children's literature and (play)didactic texts are accentuated; on the other hand, various media and pop-cultural formats from the fields of computer games, comic-film adaptations, films (of different genres) and puppet theater performances are gathered here, as well as issues that link material artifacts and literary narratives. Reviews in the form of essays on literary doll narratives, a photo exhibition and a ballet round off both editions. The time span extends from the Middle Ages to the present and future and shows once again how age-old questions regarding mankind and humanity are integrated into traditional lines and are carried on continuously in fascinating ways

CHEX-MATE: A non-parametric deep learning technique to deproject and deconvolve galaxy cluster X-ray temperature profiles

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 THREE HUNDRED PROJECT. 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{\it -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.Comment: 32 pages, 30 figures, 6 tables, Accepted in A&

CHEX-MATE: Constraining the origin of the scatter in galaxy cluster radial X-ray surface brightness profiles

We investigate the statistical properties and the origin of the scatter within the spatially resolved surface brightness profiles of the CHEXâ MATE sample, formed by 118 galaxy clusters selected via the SZ effect. These objects have been drawn from the Planck SZ catalogue and cover a wide range of masses, M500â =â [2â â â 15]à - 1014â Mâ , and redshift, zâ =â [0.05,â 0.6]. We derived the surface brightness and emission measure profiles and determined the statistical properties of the full sample and sub-samples according to their morphology, mass, and redshift. We found that there is a critical scale, Râ â ¼â 0.4R500, within which morphologically relaxed and disturbed object profiles diverge. The median of each sub-sample differs by a factor of â ¼10 at 0.05R500. There are no significant differences between mass- and redshift-selected sub-samples once proper scaling is applied. We compare CHEXâ MATE with a sample of 115 clusters drawn from the THE THREE HUNDRED suite of cosmological simulations. We found that simulated emission measure profiles are systematically steeper than those of observations. For the first time, the simulations were used to break down the components causing the scatter between the profiles. We investigated the behaviour of the scatter due to object-by-object variation. We found that the high scatter, approximately 110%, at R

The Three Hundred Project: the gizmo-simba run

We introduce gizmo-simba, a new suite of galaxy cluster simulations within The Three Hundred project. The Three Hundred consists of zoom re-simulations of 324 clusters with M 200≳ 1014.8, M ⊙ drawn from the MultiDark-Planck N-body simulation, run using several hydrodynamic and semi-analytical codes. The gizmo-simba suite adds a state-of-the-art galaxy formation model based on the highly successful Simba simulation, mildly re-calibrated to match z = 0 cluster stellar properties. Comparing to The Three Hundred zooms run with gadget-x, we find intrinsic differences in the evolution of the stellar and gas mass fractions, BCG ages, and galaxy colour-magnitude diagrams, with gizmo-simba generally providing a good match to available data at z ≈ 0. gizmo-simba's unique black hole growth and feedback model yields agreement with the observed BH scaling relations at the intermediate-mass range and predicts a slightly different slope at high masses where few observations currently lie. Gizmo-Simba provides a new and novel platform to elucidate the co-evolution of galaxies, gas, and black holes within the densest cosmic environments

Planck 2015 results. XXVII. The Second Planck Catalogue of Sunyaev-Zeldovich Sources

We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest all-sky catalogue of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data-sets, and is the first SZ-selected cluster survey containing > $10^3$ confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the Y5R500 estimates are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires. the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical and X-ray data-sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under- luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples