Multicolor photometry of the nearby galaxy cluster A119  

作　　者：Jin-Tao Tian Qi-Rong Yuan Xu Zhou Zhao-Ji Jiang Jun Ma Jiang-Hua Wu Zhen-Yu Wu Tian-Meng Zhang Hu Zou 

机构地区：[1]National Astronomical Observatories, Chinese Academy of Sciences, Beiiing 100012, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China [3]Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academyof Sciences, Beijing 100012, China [4]Department of Physics, Nanjing Normal University, Nanjing 210046, China [5]Department of Astronomy, Beijing Normal University, Beijing 100875, China

出　　处：《Research in Astronomy and Astrophysics》2012年第10期1381-1401,共21页天文和天体物理学研究（英文版）

基　　金：funded by the National Natural Science Foundation of China (Grant Nos. 11173016, 10873016, 11073032, 11003021 and 10803007);the National Basic Research Program of China (973 Program; Grant No. 2007CB815403)

摘　　要：This paper presents multicolor optical photometry of the nearby galaxy cluster Abell 119 （z = 0.0442） with the Beijing-Arizona-Taiwan-Connecticut system of 15 intermediate bands. Within the BATC field of view of 58＇× 58＇, there are 368 galaxies with known spectroscopic redshifts, including 238 member galaxies （called sample I）. Based on the spectral energy distributions of 1376 galaxies brighter than iBATC ---- 19.5, the photometric redshift technique and the color-magnitude relation of early-type galaxies are applied to select faint member galaxies. As a result, 117 faint galaxies were selected as new member galaxies. Combined with sample I, an enlarged sample （called sample II） of 355 member galaxies is obtained. Spatial distribution and localized velocity structure for two samples demonstrate that A119 is a dynami- cally complex cluster with at least three prominent substructures in the central region within 1 Mpc. A large velocity dispersion for the central clump indicates a merging along the line of sight. No significant evidence for morphology or luminosity segrega- tions is found in either sample. With the PEGASE evolutionary synthesis model, the environmental effect on the properties of star formation is confirmed. Faint galaxies in the low-density region tend to have longer time scales of star formation, smaller mean stellar ages, and lower metallicities in their interstellar medium, which is in agreement with the context of the hierarchical cosmological scenario.This paper presents multicolor optical photometry of the nearby galaxy cluster Abell 119 （z = 0.0442） with the Beijing-Arizona-Taiwan-Connecticut system of 15 intermediate bands. Within the BATC field of view of 58＇× 58＇, there are 368 galaxies with known spectroscopic redshifts, including 238 member galaxies （called sample I）. Based on the spectral energy distributions of 1376 galaxies brighter than iBATC ---- 19.5, the photometric redshift technique and the color-magnitude relation of early-type galaxies are applied to select faint member galaxies. As a result, 117 faint galaxies were selected as new member galaxies. Combined with sample I, an enlarged sample （called sample II） of 355 member galaxies is obtained. Spatial distribution and localized velocity structure for two samples demonstrate that A119 is a dynami- cally complex cluster with at least three prominent substructures in the central region within 1 Mpc. A large velocity dispersion for the central clump indicates a merging along the line of sight. No significant evidence for morphology or luminosity segrega- tions is found in either sample. With the PEGASE evolutionary synthesis model, the environmental effect on the properties of star formation is confirmed. Faint galaxies in the low-density region tend to have longer time scales of star formation, smaller mean stellar ages, and lower metallicities in their interstellar medium, which is in agreement with the context of the hierarchical cosmological scenario.

关 键 词：galaxies： clusters： individual （A119）- galaxies： distances and redshifts-- galaxies： evolution-- galaxies： kinematics and dynamics-- methods： data analysis 

分 类 号：P158[天文地球—天文学] P157.8