论文标题
RR Lyrae预测从银河中心到光晕的密度分布
The RR Lyrae projected density distribution from the Galactic centre to the halo
论文作者
论文摘要
从银河系通往光环的最内部区域的特征，将AB RR Lyre（RRAB）型恒星的预计密度分布进行了特征，其目的是对Galaxys Evolution施加限制。编译的样品（N_RRAB = 64,850）源于VVV，OGLE和GAIA调查确定的基本模式RR Lyrae变量。在三个径向间隔内，三个电源定律非常适合分布。在最内部的区域（r <2.2 ge），分布遵循sigma_rrab [1] propto r ^（-0.94 +-0.051），而在外部区域，分布分布遵守sigma_rrab [2] propto r ^（-1.50 +-0.019），以2.2 deg <r <8.0 dg <r <r <r <8.0 deg and 3] propto and 3] propto rab [3] 3] 8.0度<r <30.0度相反，红色团块（RC）巨头的累积分布在平均值上表现出更集中的分布，但是在中央r <2.2 g摄氏度中，RRAB种群的峰值更高，而球状簇（GCS）遵循密度功率法（sigma_gcs propto r ^（ - 1.59 +-0.060），rr <30.0.0 negrib the sigma_gcs prop a prop a rrab群体，rrab群体的含量更高。金属贫困子样本（[Fe/H] <-1.1 dex）。分析得出的主要结论是，RRAB分布有利于创建中央银河系区域重要的一部分（> 18％）的星团群集和合并方案。含有一半人群（一半种群半径）的半径为r_h = 6.8度（0.99 kpc），R_H = 4.2摄氏度（0.61 kpc），R_H = 11.9度（1.75 kpc）（1.75 kpc），RRAB恒星，RC巨头和GCS分别为GCS。最后，实际上只发现了1％的恒星（根据我们的考虑因素）中最内部的区域（r <35 pc），其中RRAB的总数：N SIM 1,562。这种赤字将通过像Nancy Grace Roman太空望远镜（以前是WFIRST）这样的未来太空任务来大大改善。
The projected density distribution of type ab RR Lyrae (RRab) stars was characterised from the innermost regions of the Milky Way to the halo, with the aim of placing constraints on the Galaxys evolution. The compiled sample (N_RRab = 64,850) stems from fundamental mode RR Lyrae variables identified by the VVV, OGLE, and Gaia surveys. The distribution is well fitted by three power laws over three radial intervals. In the innermost region (R < 2.2 deg) the distribution follows Sigma_RRab[1] propto R ^(-0.94 +- 0.051), while in the external region the distribution adheres to Sigma_RRab[2] propto R^(-1.50 +- 0.019) for 2.2 deg< R <8.0 deg and Sigma_RRab[3] propto R ^(-2.43 +- 0.043) for 8.0 deg < R <30.0 deg. Conversely, the cumulative distribution of red clump (RC) giants exhibits a more concentrated distribution in the mean, but in the central R < 2.2 deg the RRab population is more peaked, whereas globular clusters (GCs) follow a density power law (Sigma_GCs propto R ^(-1.59 +- 0.060) for R<30.0 deg) similar to that of RRab stars, especially when considering a more metal-poor subsample ([Fe/H]<-1.1 dex). The main conclusion emerging from the analysis is that the RRab distribution favours the star cluster infall and merger scenario for creating an important fraction (>18 %) of the central Galactic region. The radii containing half of the populations (half populations radii) are R_H=6.8 deg (0.99 kpc), R_H =4.2 deg (0.61 kpc), and R_H =11.9 deg (1.75 kpc) for the RRab stars, RC giants, and GCs, respectively. Finally, merely 1% of the stars have been actually discovered in the innermost region (R < 35 pc) out of the expected (based on our considerations) total number of RRab therein: N sim 1,562. That deficit will be substantially ameliorated with future space missions like the Nancy Grace Roman Space Telescope (formerly WFIRST).
