Smithsonian Astrophysical Observatory, 60 Garden Street MS09, Cambridge, MA 02138, USA. Sternberg Astronomical Institute, Moscow State University, 13 Universitetsky prospect, Moscow 119992, Russia.
Sternberg Astronomical Institute, Moscow State University, 13 Universitetsky prospect, Moscow 119992, Russia. L'Institut de Recherche en Astrophysique et Planétologie, 9 Avenue du Colonel Roche BP 44346, 31028, Toulouse Cedex 4, France.
Science. 2015 Apr 24;348(6233):418-21. doi: 10.1126/science.aaa3344. Epub 2015 Apr 23.
Compact elliptical galaxies form a rare class of stellar system (~30 presently known) characterized by high stellar densities and small sizes and often harboring metal-rich stars. They were thought to form through tidal stripping of massive progenitors, until two isolated objects were discovered where massive galaxies performing the stripping could not be identified. By mining astronomical survey data, we have now found 195 compact elliptical galaxies in all types of environment. They all share similar dynamical and stellar population properties. Dynamical analysis for nonisolated galaxies demonstrates the feasibility of their ejection from host clusters and groups by three-body encounters, which is in agreement with numerical simulations. Hence, isolated compact elliptical and isolated quiescent dwarf galaxies are tidally stripped systems that ran away from their hosts.
致密椭圆星系形成了一类罕见的恒星系统（目前已知约 30 个），其特征为恒星密度高、体积小，且通常含有富金属恒星。它们被认为是通过大质量原星系的潮汐剥离形成的，直到发现了两个孤立的物体，在那里无法识别执行剥离的大质量星系。通过挖掘天文调查数据，我们现在已经在各种环境中发现了 195 个致密椭圆星系。它们都具有相似的动力学和恒星种群特性。对非孤立星系的动力学分析表明，它们可以通过三体碰撞从宿主星系团和星系群中被抛出，这与数值模拟结果一致。因此，孤立的致密椭圆星系和孤立的静止矮星系是被潮汐剥离的系统，它们已经从其宿主星系中逃逸。
