论文标题
对Draco Draco矮人球形银河系中的RR Lyre人口的崭新了解
A fresh look at the RR Lyrae population in the Draco dwarf spheroidal galaxy with Gaia
论文作者
论文摘要
我们介绍了Draco Dwarf球形星系（DSPH）中的285颗RR Lyre Star（RRL）的目录，该目录是通过组合来自许多不同调查的数据，包括欧洲太空空间代理（ESA）基石Mission Gaia（包括第二个数据释放（DR2））获得的。我们首次使用Gaia G波段亮度金属关系（Mg- [Fe/H]）确定了样品中RRL的个体距离，并研究了Draco DSPH的结构，以其RRL种群追溯。我们发现，位于德拉科西部/西南地区的RRL似乎更靠近我们，这可能是Draco与银河系之间的相互作用线索（MW）。用RRL测量的Draco的平均距离模量为19.53 +/- 0.07 mag，对应于80.5 +/- 2.6 kpc，与先前的文献确定非常吻合。基于RRL的脉动特性，我们确认了Draco的Oosterhoff间隔性质。我们提供了Draco中41个候选RRL的其他样本，我们根据其G波段幅度的不确定性从Gaia DR2目录中选择了样本。在Gaia第三数据发布（DR3）中将可用的其他时期数据将有助于确认这些候选人是否是善意的Draco RRL。
We present a catalogue of 285 RR Lyrae stars (RRLs) in the Draco dwarf spheroidal galaxy (dSph), obtained by combining data from a number of different surveys including the second data release (DR2) of the European Space Agency (ESA) cornerstone mission Gaia. We have determined individual distances to the RRLs in our sample using for the first time a Gaia G-band luminosity-metallicity relation (MG - [Fe/H]) and study the structure of the Draco dSph as traced by its RRL population. We find that the RRLs located in the western/south-western region of Draco appear to be closer to us, which may be a clue of interaction between Draco and the Milky Way (MW). The average distance modulus of Draco measured with the RRLs is 19.53 +/- 0.07 mag, corresponding to a distance of 80.5 +/- 2.6 kpc, in good agreement with previous determinations in the literature. Based on the pulsation properties of the RRLs we confirm the Oosterhoff-intermediate nature of Draco. We present an additional sample of 41 candidate RRLs in Draco, which we selected from the Gaia DR2 catalogue based on the uncertainty of their G-band magnitudes. Additional epoch data that will become available in the Gaia third data release (DR3) will help to confirm whether these candidates are bona-fide Draco RRLs.
