论文标题
GD-1恒星流的速度分散
Velocity Dispersion of the GD-1 Stellar Stream
论文作者
论文摘要
潮汐溶解的球状簇形成了薄恒星流，可保留其过去进化的历史记录。我们报告了GD-1 Stellar流中的径向速度分散剂$ 2.3 \ pm0.3 \，\ textrm {km} \，\ textrm {s}^{ - 1} $，使用43个光谱镜确认的样本。 GD-1速度分散剂在所调查的$ \ of 15^\ circ $ span上是恒定的。我们还测量了与主gd-1流相邻的刺激中的速度散布，并在刺激尖端发现了相似的值。令人惊讶的是，刺激距离靠近流的区域比主流动态冷。 GD-1流的不受干扰的模型的速度分散$ \ of cout0.6 \，\ textrm {km} \，\ textrm {s}^{ - 1} $，表明GD-1具有动态加热。恒星流是由球状簇引起的，在它们以银河系的到来之前，预计将具有核密度剖面的矮星系旋转，预计将体验到与GD-1中观察到的速度分散体相匹配所需的加热量。这表明GD-1已被吸收，其原始宿主星系的烙印，包括其深色遗传光环的内斜率，在今天的流中仍然可以观察到。
Tidally dissolved globular clusters form thin stellar streams that preserve a historical record of their past evolution. We report a radial velocity dispersion of $2.3\pm0.3\,\textrm{km}\,\textrm{s}^{-1}$ in the GD-1 stellar stream using a sample of 43 spectroscopically confirmed members. The GD-1 velocity dispersion is constant over the surveyed $\approx15^\circ$ span of the stream. We also measured velocity dispersion in the spur adjacent to the main GD-1 stream, and found a similar value at the tip of the spur. Surprisingly, the region of the spur closer to the stream appears dynamically colder than the main stream. An unperturbed model of the GD-1 stream has a velocity dispersion of $\approx0.6\,\textrm{km}\,\textrm{s}^{-1}$, indicating that GD-1 has undergone dynamical heating. Stellar streams arising from globular clusters, which prior to their arrival in the Milky Way, orbited a dwarf galaxy with a cored density profile are expected to have experienced the amount of heating required to match the velocity dispersion observed in GD-1. This suggests that GD-1 has been accreted and that imprints of its original host galaxy, including the inner slope of its dark-matter halo, remain observable in the stream today.
