JCJC - Programme "Jeunes chercheuses et jeunes chercheurs"

Caractérisation multi-longueurs d'ondes des propriétés statistiques de la population des amas de galaxies pour l'étude de la physique de formation et d'évolution des structures – EPAMASSTAT

Clusters of galaxies in the Universe

This project aims to improve our understanding of the formation and the evolution of structures through the study of the properties of the galaxy clusters population. Via a statistical approach, studying the baryonic component of clusters with respect to the mass, our scientific goals is to understand and to constrain the role of the various non-gravitational processes in the formation of these structures.

Statistical characterisation of the population of galaxy clusters. Implication for the formation and the evolution of large scale structures.

Our study is based on the exploitation of X-ray selected samples (from the XMM-Newton satellite), we combine the X-ray signal to the gravitational lensing signal to optimise the mass determination of clusters.<br />We also work on the construction and the exploitation of the catalogue of clusters from the Planck survey. It is a unique and powerful tool for the study of the formation and the evolution of structures due to its broad coverage in redshift (up to z~1) and in masses. In order to connect the physics of the cluster formation to this of galaxy formation, thus to the history of star formation of those very same galaxies, we do investigate the infra-red properties of clusters. With this study we constrain the physical non-gravitational processes linking the galaxy accretion in the cluster potential well with the thermodynamical state of the intra-cluster gas.<br />We do base our approach on the systematic comparison of observational results to the reliable observational predictions from theoretical models, making use of hydrodynamical numerical simulations of structure formation. This will allow us to quantify the effect and the role of non- gravitational processes at play in the intra-cluster medium in a non biased way.

The project is based on:

- Use of X-ray selected samples of galaxy clusters (observed with the XMM-Newton satellite)

- Combination of the X-ray emission with the weak gravitational lensing signal for the cluster mass determination.

- Construction and exploitation of the Planck catalogue of galaxy clusters.

- Methods of optimal combination of the X-ray and SZ signals.

- Feasibility of Herschel follow-up of Planck targets

- Cross-comparison of theoretical predictions from numerical simulations of structure formation with observational constraints, in order to understand the role of non-gravitational processes at play in clusters of galaxies.

- Calibration of the Mass-Yx relation in galaxy clusters.

- The universal galaxy cluster pressure profile from a representative sample of nearby systems (REXCESS) and the Y_SZ-M_500 relation.

- Weak lending study of a representativ sample at high redshift, and charactérisation of their mass distribution.

- The infrared luminosity of galaxy clusters.

- The impact of dust on the scaling properties of galaxy clusters.

- Infrared properties of the SDSS-maxBCG galaxy clusters.

Project EPAMASSTAT is a research project in astrophysics with principal investigator Etienne Pointecouteau. The project started in November 2006, and lasted for 44 months. It was funded by ANR for a total amount of 140 k€, for a complete gross cost of the order of 800 k€.

The natural follow-up of the project was the MULTIVERSE project: www.agence-nationale-recherche.fr/Project-ANR-11-BS56-0015

12 articles in refereed journals and 12 communications in national and international meetings. The five most significant publications are:

1. Arnaud, M. ; Pointecouteau, E. ; Pratt, G. W., 2007, A&A Letters 474 ,37 : “Calibration of the galaxy cluster M500-YX relation with XMM-Newton”

2. Giard, M. ; Montier, L. ; Pointecouteau, E. ; Simmat, E. ; 2008, A&A, 490, 547: “The infrared luminosity of galaxy clusters”

3. Da Silva, A.; Catalano, A.; Montier, L.; Pointecouteau E.; Lanoux, J.; Giard, M., 2008, MNRAS, 396,849: “The impact of dust on the scaling properties of galaxy clusters”

4. Arnaud M.; Pratt G., Piffaretti R., Pointecouteau E., 2009, A&A in press (arXiv:0910.1234): “Theuniversal galaxy cluster pressure profile from a representative sample of nearby systems (REXCESS) and the Y_SZ-M_500 relation”

5.RoncarelliM.,PointecouteauE.,GiardM.,MontierL.,PelloR.,2010,A&A512,20:“Infrared properties of the SDSS-maxBCG galaxy clusters”

Project coordination

Etienne Pointecouteau (Université)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.


Help of the ANR 140,000 euros
Beginning and duration of the scientific project: - 36 Months

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