Andromeda XVII: A New Low-Luminosity Satellite of M31
Andromeda XVII: A New Low-Luminosity Satellite of M31
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仙女座 XVII：M31 的新型低光度卫星
DOI：
10.1086/587100
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
G. Lewis
中科院分区：
文献类型：
--
作者：
M. Irwin;A. Ferguson;A. Huxor;N. Tanvir;R. Ibata;G. Lewis
我们在INT/WFC成像的基础上，在M31附近发现了一个新的矮球星系。该系统名为仙女座十七(和十七)，距离M31的投影半径为≈44kpc，使用红巨星分支的顶端测量的视线距离为794kpc±40kpc，因此正好位于M31的光晕内。红色巨型分支的颜色暗示着[Fe/H]≈-1.9的金属丰度，我们发现其绝对等数为mV≈-8.5。三个球状星团位于和xvii的主体附近，这表明可能存在联系；如果其中任何一个得到证实，它将使和xvii在微弱的dsph种群中异常罕见。XVII和XVII卫星在天空中的投影位置加强了M31卫星系统中明显的耐人寻味的对准，尽管需要注意的是，当前勘测区域存在重大深度的偏差。
We report the discovery of a new dwarf spheroidal galaxy near M31 on the basis of INT/WFC imaging. The system, Andromeda XVII (And XVII), is located at a projected radius of ≈44 kpc from M31, has a line-of-sight distance of 794 ± 40 kpc measured using the tip of the red giant branch, and therefore lies well within the halo of M31. The color of the red giant branch implies a metallicity of [Fe/H] ≈ -1.9, and we find an absolute magnitude of MV ≈ -8.5. Three globular clusters lie near the main body of And XVII, suggesting a possible association; if any of these are confirmed, it would make And XVII exceptionally unusual among the faint dSph population. The projected position on the sky of And XVII strengthens an intriguing alignment apparent in the satellite system of M31, although with a caveat about biases stemming from the current area surveyed to significant depth.