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Xiaohu Yang

十月天文论坛. Galaxy clusters and cosmology: observations. Xiaohu Yang. Shanghai Astronomical Observatory. Beijing, 16/10/2012. Constrain cosmological parameters using observations. 4% Atoms, 23% Cold Dark Matter, 73% Dark energy. 调和宇宙学. Concordance LCDM model. Dark matter. Galaxy.

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Xiaohu Yang

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  1. 十月天文论坛 Galaxy clusters and cosmology: observations Xiaohu Yang Shanghai Astronomical Observatory Beijing, 16/10/2012

  2. Constrain cosmological parameters using observations

  3. 4% Atoms, 23% Cold Dark Matter, 73% Dark energy. 调和宇宙学 Concordance LCDM model

  4. Dark matter Galaxy 从调和宇宙学到精确宇宙学 • Two types of investigations to make the link • From (theoretical) halos: model the galaxy formation/distribution • The hydrodynamical simulations • The semi-analytical galaxy formation models • Statistical modelling: the HOD/CLF models • From (observational) galaxies: model the halo (mass) distribution • Clusterings • Clusters • Galaxy-galaxy lensing • Satellite kinamatics • X-ray clusters • S-Z effect

  5. (I) 大尺度结构和宇宙学 • Large redshift surveys: • LAMOST • Using public data releases • 国际合作：AS3，BigBOSS，LSST • The correlation functions and power spectra of galaxies • To constrain cosmology and galaxy formation • N-body and hydro simulations: • To understanding the structure formation and galaxy formation • Other related work • 21cm, etc 伍向平等（第一缕曙光）；李菂等（FAST）；陈学雷等（天籁）；SKA等 • Lensing 毛淑德等

  6. LAMOST team: • 建设团队 • 运行团队 • 科学团队 • 河外 • 河内 几乎所有的国内天文单位都有某种程度的参与。

  7. HOD: understanding the clustering of galaxies • 景益鹏等（HOD）； • 褚耀泉等（成团测量）； • 冯珑珑等（小波） • 詹虎等（LSST）； • 杨小虎等（CLF) • 盘军（3PCF） • 李成（SDSS） • 张骏（lensing） • 范祖辉（lensing） • 陈学雷（再电离） • 张鹏杰 • 王慧元、王宇 Jing et al. 1998

  8. Hierarchical structure formation: from C4 • We have a C4 ( Chinese Computational Cosmology Consortium) collaboration in China. • Including members from: SHAO, PMO, NAOC, SCCAS • 景益鹏、冯珑珑、高亮、林伟鹏、盘军、康熙、赵东海、杨小虎、张鹏杰等

  9. (II) 星系团 • Clusters are the rarest objects in the Universe. • They locate at the exponential decay region of the halo mass function. • Their clusterings show the largest bias. • They were extensively used to probe the cosmological parameters. • To obtain the reliable measure of the halo masses, detailed studies of cluster properties are necessory. • Extreme environment to probe the galaxy formation. • Because of the hierarchical strucutre formation, their member galaxies are accreted at different redshift. • Serve as the strong lens to find the highest redshift galaxies.

  10. Galaxy clusters The halo mass function and bias Sheth et al. (2001)

  11. Clusters for cosmology-- 过去 • 精确宇宙学 • 寻求和暗晕质量精确挂钩 • 提高观测的完备度。 • 整合多种观测结果，减小系统误差。 Eke et al. (1996)

  12. 现状： more than cosmology • Optical clusters. • From spectroscopic surveys: cosmology, galaxy formation • From photometric surveys: strong lensing candidates, cosmological probes • 杨小虎等；文中略等 • X-ray clusters • Observations: completeness? Cool core clusters? • Hydrodynamical simulations to understand the gas properties • 徐海光等；伍向平等；朱宗宏等；方涛涛等 • Strong and weak lensing signals • Observations, model the mass distributions • Giant arcs, constrain the cosmology • 毛淑德等；付丽萍等；李国亮等；景益鹏等；张骏等 • S-Z effect • Theoretical modellings, detectablity • Stacking to get a few sigma detection • 张鹏杰等；李然等；盘军等 每个方向都有若干课题组在从事相关研究工作；上述列表很不完全。

  13. Giocoli et al. 2010 New App (1):Probe the galaxy formation

  14. Question: the faint end slope of the LFsin clusters? Rines & Geller 2008

  15. New App (2): improve the completeness • We extracted 1138 (RASS) X-ray clusters from liturature. • About 200 are cross-matched with SDSS DR7 optical groups. • The vast majority of the optical groups are not linked with any known entries. • We run our own (Growth Curve Analysis) GCA code to obtain the X-ray signals from the RASS map. • An additional ~10000 X-ray signals are obtained for groups with mass > 10^{13}Msun. Optical - X-ray clusters cross-identification Wang et al. 2011

  16. New App (3): using clusters as lens to find the first galaxies A few slides from Zheng Wei’s talk in Hefei, May 8, 2012.

  17. Candidate Galaxy at z=9.6 May 8, 2012 USTC

  18. Summary • Clusters are the rarest objects in the Universe. • They locate at the exponential decay region of the halo mass function. • Their clusterings show the largest bias. • They were extensively used to probe the cosmological parameters. • To obtain the reliable measure of the halo masses, detailed studies of cluster properties are necessory. • Optical clusters • X-ray clusters, gas properties • Strong lensing signals • SZ effect • Extreme environment to probe the galaxy formation. • Because of the hierarchical strucutre formation, their member galaxies are accreted at different redshift. • Serve as the strong lens to find the first galaxies.

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