Collaborative Research: Exploring the Galaxy and its White Dwarfs with the HET Dark Energy Experiment

德克萨斯大学奥斯汀分校和贝勒大学的这个研究小组计划对Hobby-Eberly望远镜暗能量实验(Hetdex)的现有观测结果进行新的分析，以更好地了解银河系恒星形成的历史。虽然Hetdex主要用于研究暗能量，但研究人员为银河天文学改变了调查的目的，体现了一句话：一个人的垃圾是另一个人的宝藏。研究人员将共同努力，在不同层面上接触、授权和招募天文学中代表性不足的群体。在本科生层面，调查人员将专注于通过德克萨斯大学奥斯汀分校的Tarus项目培训未被充分代表的少数民族学生。在社区层面，两位研究人员将继续参与定期的外展活动，例如透过公开讲座，并创造一个新的“Hetdex调查之星”外展之夜。研究人员将利用在Hetdex内观测到的超过100,000颗恒星的光谱来：(1)提供这些恒星的大气参数；(2)使用导出的大气参数来限制恒星晕的聚集；以及(3)对白矮星进行深入调查，以限制形成的时间尺度。与其他光谱测量相比，Hetdex测量的不偏不倚和深度(15G等22)的性质使其在拼凑我们银河系的组装方面非常强大。对这些数据的初步研究表明，径向速度是可以测量的，光谱可以用来寻找金属贫乏的恒星。研究人员将通过以下方式大大扩展这项初步研究：(1)确认Hetdex中确定的候选FGK型贫金属星，利用它们在麦克唐纳天文台使用更高分辨率仪器的优势；(2)利用FGK型和白矮星的Hetdex光谱得出恒星参数，以及(3)使用这些金属元素以公正的方式测量晕属性。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This research team from the University of Texas Austin and Baylor University plan a new analysis of existing observations from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) to better understand the history of star formation in the Milky Way galaxy. While HETDEX is primarily being used for the study of dark energy, the investigators have repurposed the survey for Galactic Astronomy, embodying the phrase ‘one person’s trash is another person treasure’. The investigators will work together to engage, empower, and recruit underrepresented groups in astronomy at various levels. At the undergraduate level, the investigators will focus on training underrepresented minority students through the TARUS program at UT Austin. At the community-wide level, both investigators will continue to participate in the regular outreach, e.g., by public lectures, and create a new ‘Stars of the HETDEX survey’ outreach night.The investigators will use the spectra of more than 100,000 stars observed within HETDEX to: (1) deliver atmospheric parameters for those stars, (2) use the derived atmospheric parameters to constrain the assembly of the stellar halo, and (3) conduct a deep survey of white dwarfs, the end products of a star's lifecycle, to constrain the timescale of formation. The unbiased and deep (15 G magnitude 22) nature of the HETDEX survey makes it extremely powerful in piecing together the assembly of our Galaxy when compared with other spectroscopic surveys. A pilot study of the data has indicated that radial velocities can be measured and that the spectra can be used to find metal-poor stars. The investigators will significantly expand upon this pilot study by: (1) confirming candidate FGK-type metal-poor stars identified in HETDEX using their advantaged access to higher-resolution instruments at McDonald Observatory; (2) deriving stellar parameters using the HETDEX spectra of FGK-type and White dwarf stars, and (3) using those metallicities to measure halo properties in an unbiased way.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.