arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0906.3022astro-ph.CO
收藏

流体动力学模拟中中心群Galvanian的演化

The Evolution of Central Group Galaxies in Hydrodynamical Simulations

R. Feldmann, C. M. Carollo, L. Mayer, A. Renzini, G. Lake, T. Quinn, G. S. Stinson, G. Yepes

摘要:

我们在高分辨率的宇宙流体动力学模拟中追踪了三个~10^13 M太阳星系群的中心星系演化。群势的演变导致,在z=0,中央星系是大规模的,气体贫乏的早期型系统的恒星速度色散支持类似于椭圆或S 0星系。它们的z~2-2.5主要祖先是质量为M* ~ 3-10 x 10^10 M_sun的恒星形成星系(20-60 M_sun/yr),在扩展的气盘中拥有大量的冷气体(~5 x 10^9 M_sun)。因此,我们的模拟表明,在z~2观测到的恒星形成星系很可能是z=0星系群中中央星系的主要祖先。它们的中心恒星密度从z~1.5到z=0保持近似恒定。相反,星系由内向外生长,在最里面的~2 kpc外获得一个恒星包层。因此,有效半径内的密度降低了两个数量级。大合并和小合并都对有效半径外的大部分质量产生了贡献,从而驱动了半质量半径的演化。在三个模拟的星系群中,其中一个星系群的中心冷却时间较短,导致z<1的中心星系群发生戏剧性的复兴,影响其形态、运动学和颜色。这段插曲最终以集团间的合并而告终。我们的模拟结果表明,在星系群中,晕质量组装,星系合并和气体吸积之间的相互作用对恒星形成历史和z=0的中央星系的形态有很大的影响。[摘要]

英文摘要:

We trace the evolution of central galaxies in three ~10^13 M_sun galaxy groups simulated at high resolution in cosmological hydrodynamical simulations. The evolution in the group potential leads, at z=0, to central galaxies that are massive, gas-poor early-type systems supported by stellar velocity dispersion resembling either elliptical or S0 galaxies. Their z~2-2.5 main progenitors are massive M* ~ 3-10 x 10^10 M_sun, star forming (20-60 M_sun/yr) galaxies which host substantial reservoirs of cold gas (~5 x 10^9 M_sun) in extended gas disks. Our simulations thus show that star forming galaxies observed at z~2 are likely the main progenitors of central galaxies in galaxy groups at z=0. Their central stellar densities stay approximately constant from z~1.5 down to z=0. Instead, the galaxies grow inside-out, by acquiring a stellar envelope outside the innermost ~2 kpc. Consequently the density within the effective radius decreases by up to two orders of magnitude. Both major and minor mergers contribute to most of the mass accreted outside the effective radius and thus drive the evolution of the half-mass radii. In one of the three simulated groups the short central cooling time leads to a dramatic rejuvenation of the central group galaxy at z<1, affecting its morphology, kinematics and colors. This episode is eventually terminated by a group-group merger. Our simulations demonstrate that, in galaxy groups, the interplay between halo mass assembly, galaxy merging and gas accretion has a substantial influence on the star formation histories and z=0 morphologies of central galaxies.[Abridged]

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑