Spectroscopy of QUEST RR Lyrae Variables: The New Virgo Stellar Stream
Spectroscopy of QUEST RR Lyrae Variables: The New Virgo Stellar Stream
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DOI：
10.1086/500130
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发表时间：
2005-10
期刊：
影响因子：
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通讯作者：
S. Duffau;R. Zinn;A. K. Vivas;G. Carraro;R. Mendez;R. Winnick;C. Gallart
中科院分区：
文献类型：
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作者：
S. Duffau;R. Zinn;A. K. Vivas;G. Carraro;R. Mendez;R. Winnick;C. Gallart
对位于类星体赤道巡天队（QUEST）确定的“12.04丛”中的18个RR型天琴座变星（RRL）进行了光谱观测，测量了它们的径向速度和金属丰度。十颗蓝色水平分支（BHB）星被斯隆数字巡天（SDSS）识别出来。在星系团的密集区，9颗恒星中有6颗在银河系静止坐标系（Vgsr）中的平均径向速度为99.8，σ = 17.3 km s-1，略小于测量的平均误差。整个样本包含8个RRL和5个BHB星，它们的Vgsr值表明它们属于这个流。对于这些RRL中的7个，[Fe/H]的测量值（内部精度为0.08 dex）得出[Fe/H] δ = -1.86，σ = 0.40。这些值表明，该星系流是一个潮汐破裂的矮球状星系的低光度。SDSS数据库中的光度测量表明，这股气流覆盖了室女座至少106平方度的天空。建议命名为室女座星流。
Eighteen RR Lyrae variables (RRLs) that lie in the "12.ͪ4 clump" identified by the Quasar Equatorial Survey Team (QUEST) have been observed spectroscopically to measure their radial velocities and metal abundances. Ten blue horizontal branch (BHB) stars identified by the Sloan Digital Sky Survey (SDSS) were added to this sample. Six of the nine stars in the densest region of the clump have a mean radial velocity in the Galactic rest frame (Vgsr) of 99.8 and σ = 17.3 km s-1, which is slightly smaller than the average error of the measurements. The whole sample contains eight RRLs and five BHB stars that have values of Vgsr suggesting membership in this stream. For seven of these RRLs, the measurements of [Fe/H], which have an internal precision of 0.08 dex, yield ⟨[Fe/H]⟩ = -1.86 and σ = 0.40. These values suggest that the stream is a tidally disrupted dwarf spheroidal galaxy of low luminosity. Photometry from the database of the SDSS indicates that this stream covers at least 106 deg2 of the sky in the constellation Virgo. The name Virgo stellar stream is suggested.