论文标题
通过人口II，恒星距离指标i：雕塑家矮人球形的距离距离本地组星系的距离
Distances to Local Group Galaxies via Population II, Stellar Distance Indicators I: The Sculptor Dwarf Spheroidal
论文作者
论文摘要
我们通过三个种群II恒星距离指标确定雕塑家矮球的距离：（a）红色巨型分支（TRGB）的尖端，（b）RR Lyrae变量（RRLS）和（c）蓝色水平分支（HB）的脊线。高信号到噪声，宽场$ vi $成像，覆盖面积$ 48'\ times 48'$，并达到的光度深度约为2磁磁带，而麦哲伦-Baaade 650万望远镜则获得了HB。发现从Sculptor的TRGB得出的真模量为$μ^\ Mathrm {trgb} _o = 19.59 \ pm 0.07_ \ mathrm {stat} \ pm 0.05_ \ pm 0.05_ \ mathrm {sys} $ mag。随着文献所采用的周期，新获取的RRL相位点与模板光曲线相吻合，以确定$μ_{w_ {w_ {i，v-i}}^\ mathrm {rrl} = 19.60 \ 19.60 \ pm 0.01_ \ pm 0.01_ \ pm mathrm {stat stat}}} \ pm 0.05 _ \ pm 0.05_ \ mathrmmathrm}最后，发现HB距离为$μ^\ MATHRM {HB} _O = 19.54 \ pm 0.03_ \ Mathrm {stat} \ pm 0.09_ \ Mathrm {sys} $ mag。每种方法的绝对校准都由独立的几何零点锚定，利用了不同的恒星，并根据相同的光度校准确定。
We determine the distance to the Sculptor Dwarf Spheroidal via three Population II stellar distance indicators: (a) the Tip of the Red Giant Branch (TRGB), (b) RR Lyrae variables (RRLs), and (c) the ridgeline of the blue horizontal branch (HB). High signal-to-noise, wide-field $VI$ imaging that covers an area $48' \times 48'$ and reaches a photometric depth approximately 2 mag fainter than the HB was acquired with the Magellan-Baade 6.5m telescope. The true modulus derived from Sculptor's TRGB is found to be $μ^\mathrm{TRGB}_o = 19.59 \pm 0.07_\mathrm{stat} \pm 0.05_\mathrm{sys}$ mag. Along with periods adopted from the literature, newly acquired RRL phase points are fit with template light curves to determine $μ_{W_{I,V-I}}^\mathrm{RRL} = 19.60 \pm 0.01_\mathrm{stat} \pm 0.05_\mathrm{sys}$ mag. Finally, the HB distance is found to be $μ^\mathrm{HB}_o = 19.54 \pm 0.03_\mathrm{stat} \pm 0.09_\mathrm{sys}$ mag. Absolute calibrations of each method are anchored by independent geometric zero-points, utilizes a different class of stars, and are determined from the same photometric calibration.
