论文标题
微弱的星系中的微弱恒星：I。Boötes的超深光度法
Faint Stars in a Faint Galaxy: I. Ultra Deep Photometry of the Boötes I Ultra Faint Dwarf Galaxy
论文作者
论文摘要
我们对Boötesi Ultra微弱矮球星系的分辨出恒星种群进行了新的极深的图像进行了分析。这些新数据是使用Hubble太空望远镜，使用高级摄像头进行调查（宽场摄像头）和宽场摄像头3（UVIS），带有滤波器F606W和F814W（本质上是V和I），作为程序的一部分，以推导该Galaxy中低质量的初始质量功能。我们比较和对比两种获得恒星光度法的方法，即EPSF和Daophot。我们根据从ACS/WFC数据的Daophot光度法获得的每个恒星在颜色标记图上的位置确定BoötesI的可能成员。可能的成员靠近恒星等线，被选为涵盖从较明亮的径向速度成员恒星的光谱数据得出的已知金属性分布，并且与主序列的关节一致。 Boötesi Galaxy的最终发光函数在F814W中的完整性极限为27.4，而F606W（Vega幅度系统）的完整性函数为27.4（VEGA幅度系统），该限制对应于限制性恒星质量为$ 0.3 m_ \ odot $。
We present an analysis of new extremely deep images of the resolved stellar population of the Boötes I ultra faint dwarf spheroidal galaxy. These new data were taken with the Hubble Space Telescope, using the Advanced Camera for Surveys (Wide Field Camera) and Wide Field Camera 3 (UVIS), with filters F606W and F814W (essentially V and I), as part of a program to derive the low-mass stellar initial mass function in this galaxy. We compare and contrast two approaches to obtaining the stellar photometry, namely ePSF and DAOPHOT. We identify likely members of Boötes I based on the location of each star on the color-magnitude diagram, obtained with the DAOPHOT photometry from the ACS/WFC data. The probable members lie close to stellar isochrones that were chosen to encompass the known metallicity distribution derived from spectroscopic data of brighter radial-velocity member stars and are consistent with the main-sequence turnoff. The resulting luminosity function of the Boötes I galaxy has a 50% completeness limit of 27.4 in F814W and 28.2 in F606W (Vega magnitude system), which corresponds to a limiting stellar mass of $\le 0.3 M_\odot$.
