...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The Astrophysical Journal. Letters >A peculiar faint satellite in the remote outer halo of M31
【24h】

A peculiar faint satellite in the remote outer halo of M31

机译：M31遥远的外部光环中的一颗奇特的微弱卫星

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We present Hubble Space Telescope imaging of a newly discovered faint stellar system, PAndAS-48, in the outskirts of the M31 halo. Our photometry reveals this object to be comprised of an ancient and very metal-poor stellar population with age ? 10 Gyr and [Fe/H] ? -2.3. Our inferred distance modulus (m-M)_0 = 24.57 ± 0.11 confirms that PAndAS-48 is most likely a remote M31 satellite with a three-dimensional galactocentric radius of kpc. We observe an apparent spread in color on the upper red giant branch that is larger than the photometric uncertainties should allow, and briefly explore the implications of this. Structurally, PAndAS-48 is diffuse, faint, and moderately flattened, with a half-light radius pc, integrated luminosity M_V = -4.8 ± 0.5, and ellipticity. On the size-luminosity plane it falls between the extended globular clusters seen in several nearby galaxies and the recently discovered faint dwarf satellites of the Milky Way; however, its characteristics do not allow us to unambiguously classify it as either type of system. If PAndAS-48 is a globular cluster then it is among the most elliptical, isolated, and metal-poor of any seen in the Local Group, extended or otherwise. Conversely, while its properties are generally consistent with those observed for the faint Milky Way dwarfs, it would be a factor of ～2-3 smaller in spatial extent than any known counterpart of comparable luminosity.
机译：我们介绍了哈勃太空望远镜在M31光晕郊区发现的一个新发现的微弱恒星系统PAndAS-48的影像。我们的光度法揭示了这个物体是由年龄远大且金属贫乏的恒星族组成的？ 10 Gyr和[Fe / H]？ -2.3。我们推断的距离模数（m-M）_0 = 24.57±0.11证实了PAndAS-48最有可能是遥测的M31卫星，其立体角半径为kpc的三维。我们观察到上部红色巨型分支上的表观颜色散布大于光度不确定性应允许的范围，并简要探讨了其含义。在结构上，PAndAS-48呈散光，微弱且适度平坦，半径为pc的一半，综合亮度M_V = -4.8±0.5，并且具有椭圆率。在大小光度平面上，它落在几个附近星系中看到的延伸的球状星团和最近发现的银河系矮矮星之间。但是，它的特性不允许我们明确地将其分类为任何一种系统。如果PAndAS-48是球状星团，则它是本地组中任何椭圆形的，孤立的，金属贫乏的，无论是扩展的还是其他的。相反，尽管它的性质通常与微弱的银河系矮星的观测到的一致，但与任何已知的具有类似光度的对应物相比，它的空间范围要小2-3倍。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号