Infrared Beacons in the Universe - J Band Spectroscopy of Red Supergiants and the Chemical Composition of Star Forming Galaxies

宇宙中的红外信标 - 红超巨星的 J 波段光谱和恒星形成星系的化学成分

• 批准号: 1108906
• 负责人: Rolf-Peter Kudritzki
• 金额: $ 22.99万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1108906&HistoricalAwards=false
• 关键词: Infrared; Beacons; Universe; Band; Spectroscopy

Determining the chemical composition of galaxies is crucial for understanding their formation and evolution. Standard techniques, utilizing emission line spectra of the diffuse interstellar gas (specifically HII regions), is plagued by large and poorly understood systematic uncertainties. This project will develop a new, and potentially transformative, approach based on near-infrared spectroscopy of individual red supergiant stars. The output of these stars peaks in the J-band, where the spectra are rich in atomic lines. New multi-object infrared spectrographs on 10-meter-class telescopes will be able to obtain sufficient resolution to derive accurate abundances to distances of 10 megaparsecs. The purpose of this project is to develop, validate and exploit this new technique, in several steps: (1) The technique will be tested in the Milky Way and the Magellanic Clouds, against complementary techniques using HII region and blue supergiant star spectra; (2) Local Group galaxies of extremely low metallicity (NGC 3109, WLM, IC 1613) and the spirals M31 and M33 will be studied and compared with results from blue supergiants; (3) the technique will be applied to spiral galaxies beyond the Local Group out to a few megaparsecs (NGC 300, NGC 2403, M81). Accurate abundances and abundance gradients will be obtained, allowing constraints on the evolutionary states and histories of star forming galaxies, as well as an assessment of the reliability of H II region techniques. The method will also be extended to super-star clusters, which contain many dozens of red supergiants dominating the J-band flux, and which may be useful as cosmological abundance indicators at even larger distances. Eventually, this technique may be best exploited by the next generation of large telescopes, achieving abundance measurements out to 100 megaparsecs, a substantial volume of the local universe. The project will support the work of one graduate student, who will participate in international collaborations. Results will be incorporated into education and public outreach activities conducted by the Principal Investigator.

确定星系的化学成分对于理解它们的形成和演化至关重要。标准的技术，利用发射线光谱的弥漫星际气体（特别是HII区域），是困扰着大的和了解甚少的系统不确定性。该项目将开发一种新的、可能具有变革性的方法，该方法基于单个红超巨星的近红外光谱。这些恒星的输出在J波段达到峰值，那里的光谱富含原子线。10米级望远镜上的新的多目标红外光谱仪将能够获得足够的分辨率，以获得10兆秒差距距离的精确丰度。该项目的目的是发展、验证和利用这项新技术，分几个步骤：（1）将在银河系和麦哲伦云中对这项技术进行测试，并与使用HII区和蓝超巨星星星光谱的补充技术进行比较;（2）金属丰度极低的本星系群星系（NGC 3109，WLM，IC 1613）和螺旋M31和M33的研究，并与蓝超巨星的结果进行比较;（3）该技术将应用于本星系群以外的几个百万秒差距的旋涡星系（NGC 300，NGC 2403，M81）。将获得精确的丰度和丰度梯度，从而限制形成星星的星系的演化状态和历史，以及评估H II区技术的可靠性。该方法还将扩展到超级星团，其中包含数十个控制J波段通量的红超巨星，并且可能在更大的距离上作为宇宙学丰度指标。最终，这种技术可能会被下一代大型望远镜最好地利用，实现100兆秒差距的丰度测量，这是当地宇宙的一个相当大的体积。该项目将支持一名研究生的工作，他将参加国际合作。研究结果将纳入主要研究者开展的教育和公共宣传活动。