【摘要】 基于SDSS和NED关于星系团Abell 1795的1.5 h-1Mpc范围内154个成员星系的位置和红移信息,对该团的动力学结构和形态进行了分析.计算出中心cD星系的本动速度为235±72 km.s-1,说明cD星系在星系团完全维里化之前就已经形成.从这些星系的空间投影分布和局域视向速度分布中,发现了正在并合之中的一个子团,进一步说明了该星系团并未处于动力学平衡状态.该星系团中心区域早型星系的比例显著偏高,说明中心区域的恒星形成率偏低.外围区域晚型星系所占的比例略高,可能预示着气体、尘埃等的存在,表现出恒星形成的活跃.团星系的空间延展方向和中心cD星系的方位角一致,在观测上支持了等级成团理论.更多还原

【Abstract】 Based on the position and redshift information of 154 member galaxies of Abell 1795 within 1.5 h-1Mpc from SDSS and NED database,the morphology and dynamical structure of this cluster are analyzed.The peculiar velocity of the central cD galaxy is estimated as 235±72 km·s-1,indicating that the cD galaxy was formed before the complete virialization.From the spatial distribution and localized velocity variation,a subcluster moving towards cluster center is found.The significant high fraction of early-type galaxies in central region suggests lower star formation in this area.A little higher fraction of late-type galaxies in outer region seems to indicate existence of the gas and dust,which displays an active star formation.The extension direction of cluster galaxies is consistent with the position angle of the central cD galaxy,which observationally supports the hierachical model of cluster formation.更多还原