Collaborative Project: Observations of Cepheids in Local Group Galaxies

合作项目：观测本星系群中的造父变星AST-9987347这是一个合作项目，旨在获得M31和M33星系中造父变星的径向速度曲线和丰度测定。造父变星是确定河外距离尺度的主要手段。这个项目将测试我们银河系外的造父变星及其卫星麦哲伦云遵循相同的周期-光度-丰度关系的假设。候选人将从对附近星系的直接光度测量中收集到。候选人的光谱观测将使用麦克唐纳天文台的霍比-埃伯利望远镜进行。这一结果将提供第一批直接校准局部星系群中的距离的方法之一，并有助于改进确定哈勃常数所依赖的河外距离标度。该项目的资金由NSF恒星天文与天体物理学计划(AST/SAA)提供。

ABSTRACTMoffett, Thomas"Collaborative Project: Observations of Cepheids in Local Group Galaxies"AST-9987347This is a collaborative project to obtain radial velocity curves and abundance determinations for Cepheid variable stars in the galaxies M31 and M33. Cepheid variable stars provide the primary means for determining the extragalactic distance scale. This project will test the assumption that Cepheids outside our own Milky Way Galaxy and its satellites the Magellanic Clouds follow the same period-luminosity-abundance relation. Candidates will be gleaned from the DIRECT photometry survey of nearby galaxies. The spectroscopic observations of candidates will be performed with the Hobby-Eberly Telescope at McDonald Observatory. The results will provide one of the first direct calibrations of distances in the Local Group of galaxies, and help refine the extragalactic distance scale upon which the determination of the Hubble constant depends.Funding for this project was provided by the NSF program for Stellar Astronomy & Astrophysics (AST/SAA).