Discovery of Andromeda XIV: A Dwarf Spheroidal Dynamical Rogue in the Local Group?
Discovery of Andromeda XIV: A Dwarf Spheroidal Dynamical Rogue in the Local Group?
复制标题
仙女座 XIV 的发现：本地群体中的矮球体动力学盗贼？
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
D. Reitzel
中科院分区：
文献类型：
--
作者：
S. Majewski;S. Majewski;Rachael L. Beaton;Rachael L. Beaton;R. Patterson;J. Kalirai;M. Geha;Ricardo R. Muñoz;M. Seigar;M. Seigar;P. Guhathakurta;K. Gilbert;R. M. Rich;James S. Bullock;D. Reitzel
在我们对仙女座星系外晕的观测过程中，我们发现了一个遥远的、可能是该系统的卫星，其投影半径为162千秒差距（11.7°）。这颗相当细长的矮星（椭圆率为0.31 ± 0.09）可以用1.07 kpc（d/784 kpc）的King轮廓来拟合，其中卫星距离d估计为630-850 kpc，距离红巨星分支的尖端。新发现的星系“仙女座XIV”（“And XIV”）以其极端的动力学特征与其他本星系群星系区分开来;凯克/DEIMOS光谱显示它有很大的日心径向速度（-481 km s-1），或相对于M31的速度为-206 km s-1。根据最新的M31质量模型，即使在它的投影半径和XIV也已经达到了M31的逃逸速度。如果And XIV与M31结合，那么最近的M31维里质量减少的模型需要向上修正。如果不与M31绑定，那么And XIV现在第一次落入本星系群，代表一个矮星系，它几乎在孤立中形成并度过了它的整个生命。
In the course of our survey of the outer halo of the Andromeda galaxy we have discovered a remote, possible satellite of that system at a projected 162 kpc (11.7°) radius. The fairly elongated (0.31 ± 0.09 ellipticity) dwarf can be fit with a King profile of 1.07 kpc (d/784 kpc) limiting radius, where the satellite distance, d, is estimated at ~630-850 kpc from the tip of the red giant branch. The newfound galaxy, "Andromeda XIV" ("And XIV"), distinguishes itself from other Local Group galaxies by its extreme dynamics; Keck/DEIMOS spectroscopy reveals it to have a large heliocentric radial velocity (-481 km s-1), or -206 km s-1 velocity relative to M31. Even at its projected radius And XIV already is at the M31 escape velocity based on the latest M31 mass models. If And XIV is bound to M31, then recent models with reduced M31 virial masses need revision upward. If not bound to M31, then And XIV is just now falling into the Local Group for the first time and represents a dwarf galaxy that formed and spent almost its entire life in isolation.