Biases in hydrostatic mass profiles introduced by hot gas substructures:Chandra study of four galaxy clusters  

作　　者：Li-Yi Gu Yu Wang Jun-Hua Gu Jing-Ying Wang Zhen-Zhen Qin Meng-Yu Yao Jian-Long Yang Hai-Guang Xu 

机构地区：[1]Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China

出　　处：《Research in Astronomy and Astrophysics》2010年第10期1005-1012,共8页天文和天体物理学研究（英文版）

基　　金：supported by National Natural Science Foundation of China(Grant Nos.10673008,10878001and10973010);the Ministry of Science and Technology of China(Grant No.2009CB824900/2009CB24904);the Ministry of Education of China(the NCET Program)

摘　　要：By analyzing the azimuthal variations of total gravitating mass profiles in the central 300 h^-1 71 kpc regions of four galaxy clusters with Chandra data, we find that the azimuthally-averaged mass profiles may have been systematically underestimated by 16^＋9 -8% at lσ significance in the 50-100 h^-1 71 kpc regions, probably due to the prevailing existence of 2-D hot gas substructures in 100-300h^-1 71 kpc. The mass biases become negligible（-7＋11 _9＋ %） at 〉 150 h^-1 71 kpc. We confirm the results that the gas temperature maps can be used to probe the departure from hydrostatic equilibrium and help quantify the systematic biases in X-ray mass measurements in the central regions of clusters.By analyzing the azimuthal variations of total gravitating mass profiles in the central 300 h^-1 71 kpc regions of four galaxy clusters with Chandra data, we find that the azimuthally-averaged mass profiles may have been systematically underestimated by 16^＋9 -8% at lσ significance in the 50-100 h^-1 71 kpc regions, probably due to the prevailing existence of 2-D hot gas substructures in 100-300h^-1 71 kpc. The mass biases become negligible（-7＋11 _9＋ %） at 〉 150 h^-1 71 kpc. We confirm the results that the gas temperature maps can be used to probe the departure from hydrostatic equilibrium and help quantify the systematic biases in X-ray mass measurements in the central regions of clusters.

关 键 词：cosmology dark matter -- galaxies CLUSTERS general -- galaxies inter-galactic medium -- X-rays GALAXIES CLUSTERS 

分 类 号：O212.6[理学—概率论与数理统计] TQ530.2[理学—数学]