GHOSTS: the Nature of Galactic Stellar Halos from Resolved Stellar Populations

幽灵：来自已解析恒星群的银河系恒星晕的本质

• 批准号: 126360709
• 负责人: Dr. Roelof S. de Jong
• 金额: --
• 依托单位: Leibniz-Institut für Astrophysik Potsdam (AIP)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/126360709?language=en
• 关键词: GHOSTS; Nature; Galactic; Stellar; Halos

In recent years we have started to appreciate that the outskirts of galaxies contain valuable information about the formation process of galaxies. In hierarchical galaxy formation the stellar halos and thick disks of galaxies are thought to be the result of accretion of minor satellites, predominantly in the earlier assembly phases. The size, metallicity, and amount of substructure in current day halos are therefore directly related to issues like the small scale properties of the primordial power spectrum of density fluctuations and the suppression of star formation in small dark matter halos.To exploit this fossil record of the galaxy formation process I have initiated the GHOSTS imaging survey of the resolved stellar populations of 18 nearby, massive disk galaxies. Here I request funding to expand this program of 200+ HST orbits with ground-based Large Binocular Telescope imaging and analyse the combined data sets. We will use bright tracer RGB stars to measure halo surface brightness profiles to extremely low equivalent surface brightness levels out to ~ 60 kpc. The colors of these old RGB stars are also excellent metallicity indicators putting further constraints on formation history. Younger Main Sequence, He burning and AGB stars constrain evolution of outer disk regions. The amount of halo substructure will be compared against the latest hierarchical galaxy formation models.

近年来，我们开始意识到星系的外围蕴藏着有关星系形成过程的宝贵信息。在分层星系形成中，恒星晕和星系厚盘被认为是小卫星吸积的结果，主要是在早期组装阶段。因此，当今晕中亚结构的大小、金属丰度和数量与密度波动的原始功率谱的小尺度特性以及小型暗物质晕中恒星形成的抑制等问题直接相关。星系形成过程 我已经启动了 GHOSTS 成像调查，对附近 18 个大质量盘状星系的已解析恒星群进行了调查。在这里，我请求资金来扩展这个由 200 多个 HST 轨道组成的项目，利用地面大型双目望远镜成像并分析组合数据集。我们将使用明亮的示踪 RGB 星来测量光环表面亮度剖面，以达到约 60 kpc 的极低等效表面亮度水平。这些古老的 RGB 恒星的颜色也是极好的金属丰度指标，进一步限制了形成历史。较年轻的主序、He燃烧和AGB恒星限制了外盘区域的演化。晕子结构的数量将与最新的分层星系形成模型进行比较。

项目成果

Outer Spiral Disks as Clues to Galaxy Formation and Evolution

外螺旋盘作为星系形成和演化的线索

• DOI: 10.1071/as09067
• 发表时间: 2010
• 期刊: Publications of the Astronomical Society of Australia
• 影响因子: 6.3
• 作者: Vlajić

THE GHOSTS SURVEY. I. HUBBLE SPACE TELESCOPE ADVANCED CAMERA FOR SURVEYS DATA

幽灵调查 I 哈勃太空望远镜先进相机用于调查数据

• DOI: 10.1088/0067-0049/195/2/18
• 发表时间: 2011
• 期刊: The Astrophysical Journal Supplement Series
• 作者: Radburn-Smith;de Jong;Bailin;Bullock;Courteau;Dalcanton;Ferguson;Goudfrooij;Holfeltz;Holwerda;Purcell;Streich;Vlajić
• 通讯作者: Vlajić

THE STRUCTURE AND METALLICITY GRADIENT IN THE EXTREME OUTER DISK OF NGC 7793

• DOI: 10.1088/0004-637x/732/1/7
• 发表时间: 2011-01
• 期刊: The Astrophysical Journal
• 作者: M. Vlajić;J. Bland-Hawthorn;K. Freeman