Stepping Stones to the Universe: DIRECT Distances to the M31 and the M33 Galaxies

通往宇宙的垫脚石：到M31和M33星系的直接距离萨塞洛夫博士Sasselov正在进行一个名为DIRECT的项目。 这个项目使用分离的食双星和造父变星来改进宇宙学距离阶梯中两个重要星系的距离。 微透镜搜索现在正在寻找分离的食双星。 塞萨洛夫博士正在扩大这些搜索范围，以包括北方天空中可见的两个主要本星系群，M31和M33。这两个邻近的星系是我们目前大部分努力在大尺度上理解宇宙演变的垫脚石。 它们对校准河外距离标度至关重要。它们限制了早期星系形成和演化的人口合成模型，并提供了恒星光度校准。

Stepping stones to the Universe: DIRECT distances to the M31 and the M33 galaxiesDimitar D. SasselovDr. Sasselov is conducting a project called DIRECT. This project uses detached eclipsing binaries and Cepheids to refine the distances to two important galaxies in the cosmological distance ladder. Microlensing searches are now finding detached eclipsing binaries. Dr. Sasselov is extending these searches to include the two main Local Group galaxies visible in the northern sky, M31 and M33. These two nearby galaxies are stepping stones for most of our current efforts to understand the evolving universe at large scales. They are essential to the calibration of the extragalactic distance scale. They constrain population synthesis models for early galaxy formation and evolution and provide the stellar luminosity calibration.