The Calcium Triplet in the Near Infrared: Its Calibration and Use in Determining the Evolution of the Large Magellanic Cloud

近红外钙三重态：其校准及其在确定大麦哲伦星云演化中的应用

• 批准号: 0070985
• 负责人: Tammy Smecker-Hane
• 金额: $ 17.11万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0070985&HistoricalAwards=false
• 关键词: Calcium; Triplet; Near; Infrared; Its

AST-0070985Tammy Smecker-HaneThe goals of this proposal are to: a) Obtain spectra (in the wavelength region of the 8000-Angstrom calcium triplet) of 10 to 20 red giant stars in 11 Galactic clusters and determine (using stellar atmospheres ) the calibration of the CaII triplet as a metallicityindicator. b) Obtain spectra of ~110 Red Giants in each of 3 regions in LMC and apply the calibration from the Galactic cluster giants to determine the LMC giant's metallicity and thus determine the star formation history in the LMC . The LMC observations will aid in understanding how local variations in star-formation history are distributed. This, in turn, will help us to understand star-formation in intermediate redshift galaxies.One of the fundamental goals of modern astrophysics is to understand how galaxies have evolved. A galaxy's evolution can be determined by measuring the chemical compositions and ages of its stars. In this project, Professor Smecker-Hane and collaborators will accomplish two goals. First, they will calibrate the depth of calcium absorption lines in the near-infrared spectra of stars as a function of age and chemical composition. They will extend the current calibration to younger and more metal-rich stars so the calcium lines can be used to investigate other galaxies which have stars with ages from 2 to 15 billion years and chemical compositions from one to one-thousandth of the Sun. Second, these investigators will use this new calibration to determine the chemical composition of stars as a function of radius in the Large Magellanic Cloud (LMC) using Cerro Tololo InterAmerican 4 meter Telescope in Chile. The LMC is a gas-rich, intermediate-mass galaxy with a distance of only 160,000 light years, which makes it one of the Milky Way's nearest neighbors. They will combine the chemical compositions with data from the Hubble Space Telescope in order to accurately measure the LMC's star-formation history. Existing data hints that the LMC experienced a significant burst of star formation approximately 3 to 5 billion years ago, and understanding the details of the burst -- its strength, duration, and cause - can give us valuable clues about the nature of star bursts frequently seen in faint blue galaxies at intermediate redshifts. Funding for this project was provided by the NSF program for ExtragalacticAstronomy & Cosmology (AST/EXC).***

AST-0070985Tammy Smecker-HaneThe goals of this proposal are to: a) Obtain spectra (in the wavelength region of the 8000-Angstrom calcium triplet) of 10 to 20 red giant stars in 11 Galactic clusters and determine (using stellar atmospheres ) the calibration of the CaII triplet as a metallicityindicator. b）在LMC的3个区域中的每个区域中获得〜110个红色巨人的光谱，并应用了银河系群巨头的校准以确定LMC巨头的金属性，从而确定LMC中的星形形成历史。 LMC观察结果将有助于了解恒星形成史的局部变化。反过来，这将有助于我们了解中间红移星系中的恒星形成。现代天体物理学的基本目标之一是了解星系如何发展。可以通过测量其恒星的化学成分和年龄来确定星系的演化。在这个项目中，Smecker-Hane教授和合作者将实现两个目标。首先，他们将校准恒星近红外光谱中钙吸收线的深度，这是年龄和化学成分的函数。 它们将将当前的校准扩展到年轻且富含金属的恒星，因此钙线可用于调查其他具有2至150亿年龄的恒星的星系，化学成分从1到千分之一的太阳。其次，这些研究者将使用这种新的校准来确定恒星的化学成分，这是智利中智利的4米望远镜Cerro Tololo Intererican Intererican 4米望远镜在大型麦哲伦云（LMC）中的半径函数。 LMC是一个富含气体的中间质量星系，距离仅160,000光年，这使其成为银河系最近的邻居之一。他们将将化学成分与哈勃太空望远镜的数据结合在一起，以准确测量LMC的星形构型历史记录。现有数据暗示，LMC大约在3至50亿年前经历了大量的恒星形成，并且了解爆发的细节（其强度，持续时间和原因）可以为我们提供有关中间红船体经常看到的淡蓝色星系中经常看到的恒星爆发性质的宝贵线索。该项目的资金由NSF外乳流术和宇宙学计划（AST/EXC）提供。***