Antitruncated Stellar Disks via Minor Mergers
Antitruncated Stellar Disks via Minor Mergers
复制标题
通过小规模合并反截断恒星盘
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
L. Hernquist
中科院分区：
文献类型：
--
作者：
J. Younger;T. J. Cox;A. Seth;L. Hernquist
我们使用流体动力学模拟的星系合并小调查的性质，在大半径的表面亮度过剩观察到的一些螺旋星系：反截断恒星盘。我们发现，这个过程可以通过两个相互竞争的效应产生反截断：（1）合并驱动的气体流入，将质量集中在主星系的中心，并收缩其内部的密度分布;（2）角动量通过相互作用向外转移，导致外盘膨胀。在我们的实验中，这需要在主盘中有大量的气体供应，并且遇到的是中等轨道角动量。我们的遗迹的恒星表面质量密度分布在定性和定量上都类似于在显示反截断的局部正面螺旋中观察到的破碎指数。此外，在早期的哈勃类型中，相对于经典截断，观察到的更频繁的反截断趋势与合并驱动的情况一致。
We use hydrodynamic simulations of minor mergers of galaxies to investigate the nature of surface brightness excesses at large radii observed in some spiral galaxies: antitruncated stellar disks. We find that this process can produce the antitruncation via two competing effects: (1) merger-driven gas inflows that concentrate mass in the center of the primary galaxy and contract its inner density profile; and (2) angular momentum transferred outward by the interaction, causing the outer disk to expand. In our experiments, this requires both a significant supply of gas in the primary disk, and that the encounter be prograde with moderate orbital angular momentum. The stellar surface mass density profiles of our remnants both qualitatively and quantitatively resemble the broken exponentials observed in local face-on spirals that display antitruncations. Moreover, the observed trend toward more frequent antitruncation relative to classical truncation in earlier Hubble types is consistent with a merger-driven scenario.