在南卡塔利娜调查中发现$\sim$ 9，000个新的RR天琴座
Discovery of $\sim$ 9,000 new RR Lyrae in the Southern Catalina Surveys
摘要：
我们提出了一个深，广域变率调查在南半球，第一次的结果。作为卡特琳娜巡天的一部分，赛丁泉巡天（SSS）覆盖了$-75^{\circ}\leqδ\leq-15^{\circ}$十进制范围内的$14,800$平方度。为了有效地挖掘巨大的SSS数据集，我们开发了两种算法：自动周期选择（APS）和自动傅立叶分解（AFD），其目的是锐化周期估计并产生鲁棒的光曲线模型。有了APS和AFD的输出，我们对南天的$10,540$ ab型RR天琴座（RRab）恒星（其中$\sim$ 90%是新的）进行了分类。以及位置信息，我们提供光度金属丰度，和未红化的距离。对于在晕中的RRab星，光度金属丰度分布的研究揭示了一个近似高斯的形状，平均金属丰度为${\rm [Fe/H]}=-1.4$ dex和分散度为$0.3$ dex。RRab金属丰度的空间研究表明，在距离银河系中心的第一个$\sim7$ kpc中没有明显的径向梯度。然而，在更远处，明显存在小的负梯度。这是补充了一个非常明显的相关性的平均RR天琴座金属丰度与距离以上的银河平面，PDMATHAMT。我们还进行了初步的子结构搜索，使用发现RRab，并提出了显着性大于$2 σ$的候选人的属性。其中最突出的是人马座矮星系的星系流系统向南延伸，向下延伸到赤纬$\sim -40°$。
英文摘要：
We present the results of a deep, wide-area variability survey in the Southern hemisphere, the first of its kind. As part of the Catalina Sky Surveys, the Siding Spring Survey (SSS) has covered $14,800$ square degrees in the declination range of $-75^{\circ}\leqδ\leq-15^{\circ}$. To mine the enormous SSS dataset efficiently we have developed two algorithms: Automatic Period Selection (APS) and Automatic Fourier Decomposition (AFD), which aim to sharpen the period estimation and produce robust lightcurve models. Armed with the APS and AFD outputs we classify $10,540$ ab-type RR Lyrae (RRab) stars ($\sim$90% of which are new) across the Southern sky. As well as the positional information we supply photometric metallicities, and unreddened distances. For the RRab stars in the halo, a study of the photometric metallicity distribution reveals a nearly Gaussian shape with a mean metallicity of ${\rm [Fe/H]}=-1.4$ dex and a dispersion of $0.3$ dex. A spatial study of the RRab metallicities shows no significant radial gradient in the first $\sim7$ kpc from the Galaxy center. However, further out, a small negative gradient is clearly present. This is complemented by a very obvious correlation of the mean RR Lyrae metallicity with distance above the Galactic plane, $z$. We have also carried out an initial substructure search using the discovered RRab, and present the properties of the candidates with significance greater than $2 σ$. Most prominent among these is a southern extension of the Sagittarius dwarf galaxy's stream system, reaching down to declinations $\sim -40°$.
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