Biased total mass of CC galaxy clusters by SZE measurements

1. School of Astrophysics "Francesco Lucchin" X Cycle, III Course - Bertinoro, May 24-29, 2009 Biased total mass of CC galaxy clusters by SZE measurements Andrea Conte Astronomy PhD, XXIII Cycle “Sapienza” University of Rome.

2. Outline • Brief introduction to the Sunyaev Zel’dovich Effect, • SZE as mass finder and its assumptions, • Discussion on the ICg properties: • electron number density • electron temperature • SZ flux simulations for two ICg templates: cool core and isothermal b model, • Bias on the cluster total mass. Andrea Conte - Biased total mass of CC galaxy clusters by SZE measurements

3. SZT ~ 218 GHz SZ (Sunyaev & Zel’dovich, 1980) SZK Sunyaev-Zel’dovich Effect SZE is the comptonization of the CMB photons by high energy electrons of the ICg. The scattering processes produce photons’ energy change. Andrea Conte - Biased total mass of CC galaxy clusters by SZE measurements

4. Xrays Xrays Xrays SZ as mass finder SZE Properties: • unique spectral shape • redshift independent •  electron pressure in cluster atmospheres (Mohr and Carlstrom) • Cosmology: • H0 • B • evolution of abundance of clusters • TCMB(z) (Luzzi, …, Conte et al., in preparation) • Galaxy clusters Physics: •  optical depth • Te electron temperature • vpec peculiar velocity • M cluster total mass (Carlstrom et al., 2002) • SZ as mass finder: • large galaxy clusters’ surveys • self-similarity scaling laws Andrea Conte - Biased total mass of CC galaxy clusters by SZE measurements

5. Electron Number Density The parameterized model usually employed to study cluster physics is the isothermal b model (Cavaliere et al., 1976) The b model density distribution is integrated to get the projected X-ray surface brightness profile. (LaRoque et al., 2006) Central excess emission not correctly described (Mohr et al., 1999) If tcool < tH the ICg can “cool” e “flow” towards the cluster center. The density increases in the cluster core (in contrast with the hydrostatic model) and the gas temperature exhibits a maximum at ~2rc and then it drops down to the center. (LaRoque et al., 2006) Andrea Conte - Biased total mass of CC galaxy clusters by SZE measurements

6. Electron Temperature Following self-similarity studies, ten CC clusters from a Chandra sample have been selected. The composite radial temperature profiles is shown, after scaling the temperature and the radii, opportunely. (Conte et al. in preparation) (Bonamente et al., 2006, Morandi et al., 2007) There is not a uniquely defined average cluster temperature, it depends on the method used to extract this quantity (e.g. spectroscopic, emission weighted, gas-mass weighted). Andrea Conte - Biased total mass of CC galaxy clusters by SZE measurements

7. Analysis: MCMC SZE measurements can enhance or hide the presence of a cluster cool region. CC model Hydrostatic equilibrium within the chosen overdensity isothermal b model (Conte et al. in preparation) Andrea Conte - Biased total mass of CC galaxy clusters by SZE measurements

8. 142 GHz (Conte et al. in preparation) Analysis: SZ signal Estimation of the CMB temperature distortion due to the SZE, for the two cluster models: • several fovs used to convolve the map (@142 GHz) Andrea Conte - Biased total mass of CC galaxy clusters by SZE measurements

9. Analysis: SZ signal Estimation of the CMB temperature distortion due to the SZE, for the two cluster models: • MAD (Multi Array of Detectors) experiment spectral frequencies (142, 217, 269, 353 GHz) 3x3 array of bolometers. (Conte et al. in preparation) Andrea Conte - Biased total mass of CC galaxy clusters by SZE measurements

10. (isothermal b model of the ICg) Conclusions • Different results for different instruments: • small fov allows a better description of the cluster physics (ACT, SPT, APEX-SZ), • large fov hides the presence of the cooling flow and yields an incorrect interpretation of the detected signal or wrong assumptions on the cluster physics (Planck), • small fov and large surveys (SAGACE) • cluster total mass is biased by the different assumption on the physics of the ICg, • accurate cluster temperature profiles are needed to correctly estimate the total mass bias, • the final goal is to carefully apply scaling laws in presence of CC clusters. Andrea Conte - Biased total mass of CC galaxy clusters by SZE measurements