Stellar kinematics of dwarf galaxies from multi-epoch spectroscopy: application to Triangulum II
Stellar kinematics of dwarf galaxies from multi-epoch spectroscopy: application to Triangulum II
复制标题
来自多历元光谱的矮星系恒星运动学：在三角座 II 中的应用
DOI：
10.1093/mnras/stac1441
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发表时间：
2022
影响因子：
4.8
通讯作者：
Starkenburg, Else
中科院分区：
文献类型：
--
作者：
Buttry, Rachel;Pace, Andrew B.;Koposov, Sergey E.;Walker, Matthew G.;Caldwell, Nelson;Kirby, Evan N.;Martin, Nicolas F.;Mateo, Mario;Olszewski, Edward W.;Starkenburg, Else
我们提出了新的MMT/Hectochelle光谱测量观察沿着的视线超微弱矮星系三角座II（三II）的257颗恒星。结合以前的凯克/DEIMOS光谱的结果，我们得到一个样本，其中包括16个可能的成员三II，与多达10个独立的红移测量每星星。这个多历元的运动学数据集，我们采用的方法，我们开发，以推断二进制轨道参数从稀疏采样的径向速度曲线少至两个历元。对于以前确定的（空间未解决的）二进制系统在三II，我们推断出一个轨道的解决方案，周期，半长轴，和系统velocitythat我们然后使用在分析三II的内部运动学。尽管在双星星系统的建模方面有了改进，但目前的数据仍然不足以解决Tri II的速度色散。相反，我们发现95%的置信上限为。
We present new MMT/Hectochelle spectroscopic measurements for 257 stars observed along the line of sight to the ultrafaint dwarf galaxy Triangulum II (Tri II). Combining results from previous Keck/DEIMOS spectroscopy, we obtain a sample that includes 16 likely members of Tri II, with up to 10 independent redshift measurements per star. To this multi-epoch kinematic data set, we apply methodology that we develop in order to infer binary orbital parameters from sparsely sampled radial velocity curves with as few as two epochs. For a previously identified (spatially unresolved) binary system in Tri II, we infer an orbital solution with period, semimajor axis, and systemic velocitythat we then use in the analysis of Tri II’s internal kinematics. Despite this improvement in the modelling of binary star systems, the current data remain insufficient to resolve the velocity dispersion of Tri II. We instead find a 95 per cent confidence upper limit of.