论文标题
在黑暗能源调查的六年中识别RR Lyraia变化星星
Identifying RR Lyrae Variable Stars in Six Years of the Dark Energy Survey
论文作者
论文摘要
我们使用涉及约5,000平方英尺的深色能源调查（DES）的完整六年数据集，对RR Lyrae星颗搜索。南部的天空。使用多阶段的多变量分类和光曲线模板拟合方案，我们以每个候选者为中位数识别RR Lyrae候选者的中位数。我们检测到6,971个RR Lyrae候选者至〜335 kpc，并且估计我们的样本在〜150 kpc时完成> 70％。我们发现与其他广阔的RR Lyre目录和针对麦哲伦云和其他银河系卫星星系的RR Lyrae研究非常同意。我们使用带有固定光环扁平的损坏的law模型（Q = 0.7）拟合光滑的恒星光环密度曲线，我们发现有强有力的证据证明$ r_0 = 32.1^{+1.1} _ { - 0.9} $ kpc，内部斜率为$ n_1 = -2.54^$ n_1 = -2.54^$ n_2.54^$ n_2.54^$ n.09} _.09} -5.42^{+0.13} _ { - 0.14} $。我们使用目录来搜索具有较大尺寸和低亮度的银河系卫星星系。使用一组模拟的卫星星系，我们发现我们的基于RR Lyrae的搜索比在大型策略（$ R_H> 500 $ PC），低表面露出的矮人矮人星系中使用已解决的恒星种群的搜索更为敏感。盲目搜索大型弥漫性卫星可产生三个候选子结构。第一个可以自信地与矮星系Eridanus II相关。第二个具有与超生物矮星系图卡纳II相似的距离和适当的运动，但分开〜5度。第三个在投射到球状簇NGC 1851的投影中接近，但距离远大约10 kpc，并且在适当的运动上似乎有所不同。
We present a search for RR Lyrae stars using the full six-year data set from the Dark Energy Survey (DES) covering ~5,000 sq. deg. of the southern sky. Using a multi-stage multi-variate classification and light curve template-fitting scheme, we identify RR Lyrae candidates with a median of 35 observations per candidate. We detect 6,971 RR Lyrae candidates out to ~335 kpc, and we estimate that our sample is >70% complete at ~150 kpc. We find excellent agreement with other wide-area RR Lyrae catalogs and RR Lyrae studies targeting the Magellanic Clouds and other Milky Way satellite galaxies. We fit the smooth stellar halo density profile using a broken-power-law model with fixed halo flattening (q = 0.7), and we find strong evidence for a break at $R_0 = 32.1^{+1.1}_{-0.9}$ kpc with an inner slope of $n_1 = -2.54^{+0.09}_{-0.09}$ and an outer slope of $n_2 = -5.42^{+0.13}_{-0.14}$. We use our catalog to perform a search for Milky Way satellite galaxies with large sizes and low luminosities. Using a set of simulated satellite galaxies, we find that our RR Lyrae-based search is more sensitive than those using resolved stellar populations in the regime of large ($r_h > 500$ pc), low-surface-brightness dwarf galaxies. A blind search for large, diffuse satellites yields three candidate substructures. The first can be confidently associated with the dwarf galaxy Eridanus II. The second has a similar distance and proper motion to the ultra-faint dwarf galaxy Tucana II but is separated by ~5 deg. The third is close in projection to the globular cluster NGC 1851 but is ~10 kpc more distant and appears to differ in proper motion.
