1. The Dynamical State of Massive Galaxy Clusters Conclusions  Lensing to dynamical mass discrepancy do seems to probe the dynamical state of galaxy clusters.  Most of the low-z X-ray luminous clusters of our sample are close to a state of dynamical equilibrium.  Dynamical activity appears to be more frequent for high mass clusters  Consistent with the hierarchical scenario.  Active (merging) clusters tend to have higher ICM temperatures than expected given their masses. Conclusions  Lensing to dynamical mass discrepancy do seems to probe the dynamical state of galaxy clusters.  Most of the low-z X-ray luminous clusters of our sample are close to a state of dynamical equilibrium.  Dynamical activity appears to be more frequent for high mass clusters  Consistent with the hierarchical scenario.  Active (merging) clusters tend to have higher ICM temperatures than expected given their masses. Eduardo S. Cypriano (UCL-UK), Laerte Sodré Jr. (USP-Brazil), Jean-Paul Kneib OAMP-France) & Luis Campusano (U. de Chile) Clusters as cosmoligical probes ?  Depends strongly on a well calibrated and tight Mass × Observable relation  Widely available observables (  V T X L X S-Z ) depend on the dynamical state of the cluster  Comparison with weak-lensing equivalents allows the diagnose whether the cluster is relaxed or not Clusters as cosmoligical probes ?  Depends strongly on a well calibrated and tight Mass × Observable relation  Widely available observables (  V T X L X S-Z ) depend on the dynamical state of the cluster  Comparison with weak-lensing equivalents allows the diagnose whether the cluster is relaxed or not 1 Sample & Observations  24 Abell clusters (0.05 5  1044 erg s-1 (XBAC’s Ebeling 1996)  Imaging: V R I (330 s each) with FORS1@VLT (FoV: 6.8’  6.8’) Sample & Observations  24 Abell clusters (0.05 5  1044 erg s-1 (XBAC’s Ebeling 1996)  Imaging: V R I (330 s each) with FORS1@VLT (FoV: 6.8’  6.8’) 2 Shape measurments  Algorithm: Im2shape (Bridle et al. 1998)  Stars (PSF probes) selected by their FWHM  Shapes of galaxies are deconvolved by the local PSF  Algorithm: Im2shape (Bridle et al. 1998)  Stars (PSF probes) selected by their FWHM  Shapes of galaxies are deconvolved by the local PSF Seeing ~ 0.6” Ellip. ~ 3% STARS 10-15 gal. arcmin -2 GALAXIES 3 Shear Radial Profile  To overcame the mass sheet degeneracy we estimate mass by fitting SIS profiles to the radial shear data thus obtaining  SIS Shear Radial Profile  To overcame the mass sheet degeneracy we estimate mass by fitting SIS profiles to the radial shear data thus obtaining  SIS Singular Isothermal Sphere (SIS) 4 Detailed studies of the clusters with the highest lensing × dynamical discrepancy confirms that they are dynamically active A1451  “...establishing equilibrium after a merger event” (Valtachanov et al. 2002) 6 A2744 (AC118) 8 Girardi & Mezzetti (2001)  σ total = 1777 km/s  σ A = 1121 km/s  σ B = 682 km/s Interpretation: There are two structures along the line of sight  Particular case: Virial mass > Lensing > X-rays 1) The superposition of structures artificially increases  V 2) Lensing measures the mass of both structures 3) T X measures, based on X-ray spectra will be dominated by the more luminous structure only. 1) The superposition of structures artificially increases  V 2) Lensing measures the mass of both structures 3) T X measures, based on X-ray spectra will be dominated by the more luminous structure only. A2163  “State of violent activity” (Markevitch & Vickhlinin 2001) 7 X-ray measured ICM temperature profile (left) and distribution (right) showing a complete lack of isothermality. 5 A2744 A1451 A2163 T X ~ T SIS Lensing × dynamical mass proxies A2744 A1451 A2163  V ~  SIS  The plots show the comparison between dynamical mass proxies: X-ray temperature and galaxy velocity dispersion, with its lensing counterparts  Most clusters seems to be in equilibrium (i.e. lensing and dynamical methods in agreement) but it is not true for the hottest (T X > 8keV) and with higher vel. disp. (  V > 1100 km/s) ones.