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，星系郊区包含有关星系形成过程的有价值的信息。在分层星系中，恒星光环和星系的厚磁盘被认为是次要卫星积聚的结果，主要是在早期的组装阶段。 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.在这里，我要求资金通过基于地面的大型双眼望远镜成像扩展了200多个HST轨道的程序，并分析了组合数据集。我们将使用明亮的示踪剂RGB星来测量光环表面亮度曲线，达到极低的等效表面亮度水平至约60 kpc。这些旧的RGB星的颜色也是极好的金属性指标，对形成历史造成了进一步的限制。年轻的主要序列，他燃烧和AGB恒星限制了外盘区域的演变。将光晕子结构的数量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