Laboratory Spectroscopy in Support of Studies of Metal-Poor Galactic Halo Stars

支持贫金属银河晕恒星研究的实验室光谱学

• 批准号: 0506324
• 负责人: James Lawler
• 金额: $ 27.83万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-15 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0506324&HistoricalAwards=false
• 关键词: Laboratory; Spectroscopy; Support; Studies; Metal

AST-0506453Stephen ThorsettUniversity of California-Santa CruzPulsar InterferometryABSTRACTThe Milky Way contains between 100 million and one billion neutron stars, left behind after thesupernova explosions that distributed heavy elements throughout the Galaxy. Understanding thedistribution and properties of these stars is important for understanding Galactic chemical evolution,as well as for constraining the dynamics of supernova explosions and for illuminating the formationand life-cycles of various type of exotic compact binary systems.The most direct constraints on the neutron star distribution come from measurements of parallaxesand proper motions. In most cases, these measurements can be made only for the subclass ofneutron stars that are luminous at radio wavelengths: the radio pulsars. Even then, the closest radiopulsars are a hundred times the distance of the closest stars, and the effects of parallax and propermotion are correspondingly smaller. Only about 1% of pulsars have measured parallaxes and onlyabout 10% of pulsars have even crudely measured proper motions.Here, Thorsett and Dewey will continue their highly successful interferometry program, using theVery Large Array and the Very Long Baseline Array to make very precise astrometricmeasurements of a large sample of pulsars and address several important questions. Theinvestigation will, over the next three years, measure the birth velocity distribution of neutron starswith sufficient accuracy to constrain both the high and low velocity tails (needed to understandsupernova asymmetries and retention of neutron stars in globular clusters, respectively), and willimprove understanding of local pulsar distances and the local pulsar birthrate. This plan is basedprimarily on observations that are either underway or already approved.The investigations will include student training and support, with project data forming the basis of aPh.D. thesis. The student and the principle investigators will also maintain formal connections andparticipate in activities with the Exploratorium science museum and the COSMOS summerprogram. Co-investigator Dewey is also Education and Public Outreach Director for the UCSCbranch of Calspace, providing further outreach opportunities.External science investigations will also be enabled by both web and traditional publication of thedata gathered here. These include identification of the primary target lists for The Gamma-ray LargeArea Space Telescope and other satellite missions, and interpretation of multiwavelength pulsaremission data. Comparison of the local pulsar birthrate to the massive star birthrate, constrains theproperties of the progenitors of Type II supernovae. Pulsar velocity measurements not onlyconstrain models of their birth events, and are important input parameters to population synthesisstudies of binary systems. The observations made to identify calibration sources for the Very LongBaseline Array surveys comprise a large survey sample of 21-cm snapshots of extragalactic sources.

AST-0506453Stephen Thorsett 加州大学圣克鲁斯分校脉冲星干涉测量摘要银河系包含 1 亿到 10 亿中子星，它们是超新星爆炸后留下的，将重元素分布到整个银河系。了解这些恒星的分布和性质对于理解银河系的化学演化、限制超新星爆炸的动力学以及阐明各种类型的奇异致密双星系统的形成和生命周期都很重要。对中子星分布最直接的限制来自于视差和自行的测量。在大多数情况下，这些测量只能针对在射电波长下发光的中子星子类：射电脉冲星。即便如此，最近的射电脉冲星的距离是最近恒星距离的一百倍，视差和自行的影响也相应较小。只有大约 1% 的脉冲星测量了视差，只有大约 10% 的脉冲星甚至粗略地测量了自行。在这里，托塞特和杜威将继续他们非常成功的干涉测量计划，使用甚大阵列和甚长基线阵列对大量脉冲星样本进行非常精确的天体测量，并解决几个重要问题。这项研究将在未来三年内以足够的精度测量中子星的诞生速度分布，以约束高速尾部和低速尾部（分别需要了解超新星不对称性和中子星在球状星团中的保留），并将增进对局部脉冲星距离和局部脉冲星诞生率的理解。该计划主要基于正在进行或已批准的观察。调查将包括学生培训和支持，项目数据构成博士学位的基础。论文。学生和主要研究人员还将与 Exploratorium 科学博物馆和 COSMOS 夏季项目保持正式联系并参与活动。联合调查员杜威也是加州大学圣迭戈分校加州大学加州分校加州大学分校加州分校加州分校加州分校加州分校加州空间分校的教育和公共外展总监，提供进一步的外展机会。外部科学研究也将通过网络和传统发布这里收集的数据来实现。其中包括确定伽马射线大面积太空望远镜和其他卫星任务的主要目标列表，以及解释多波长脉冲发射数据。局部脉冲星诞生率与大质量恒星诞生率的比较，限制了 II 型超新星前身的属性。脉冲星速度测量不仅限制了其诞生事件的模型，而且是双星系统总体综合研究的重要输入参数。为确定甚长基线阵列巡天的校准源而进行的观测包括河外源 21 厘米快照的大型调查样本。