Travel support for two observers to conduct astronomical observations at the LBT during November 2019

为 2019 年 11 月期间两名观察员在 LBT 进行天文观测提供差旅费

• 批准号: 438825671
• 负责人: Privatdozent Dr. Dominik Bomans
• 金额: --
• 依托单位: Lehrstuhl für Astronomie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/438825671?language=en
• 关键词: Travel; support; two; observers; conduct

A) Unevolved galaxies should have low-masses, low-metallicities, and a strong, hard radiation fields due to many massive stars. Therefore, they should emit strong UV continuum and extremely strong emission lines. At high redshifts these dwarfish galaxies are extremely hard to study, so we need good proxies for a more detailed looks at the involved processes. Such extreme emission line galaxies and extremely blue galaxies exist even at low redhift and are prone to show lines He II emission, requiring a hard radiation fields as could be provided by very massive, low metallicity, rotating stars. The discovery of nebular CIII] and CIV emission lines in z~7 galaxies further emphasized the question for the nature of the hard radiation field needed for this emission lines to occur. Since not only very massive, low metallicity stars, but also massive X-ray binaries, accreting supermassive black hole, and even shocks may be possible sources of the hard continuum photons, the definition of a set of very local proxies is imperative, where spatial resolution and sensitivity allow a detailed study of the gas and individual ionization sources. Another intriguing class of extreme emission line galaxies are green peas, emission line galaxies with extremely strong [OIII] lines. These galaxies appear to provide good conditions for the escape of Lyman continuum radiation. We study all 3 classes of promising proxies for high redshift (proto-)galaxies in 3 observing programs at the LBT. B) The ionization process of outflows and diffuse ionized gas halos in disk galaxies is still a puzzle. While a connection to star formation activity seems to be well established (but not fully understood), the ionization mechanism of the observed ionized gas is still unclear: while photo-ionization certainly contributes, the observed line ratios and their change with distance from the disk require changes in the photon field and the presence of an additional currently unknown heating mechanism. C) Spitzer and also HERSCHEL revealed a number of small bubbles in the Milky Way. In a couple of cases, it was possible to take optical spectra of the apparent central stars, which surprisingly often turned out to be evolved massive stars (Wolf-Rayet stars, candidates for Luminous Blue Variables, and OB supergiants). We target the bubbles and their central stars with LUCI NIR spectroscopy to classify the highly absorbed part of the bubbles and investigate their evolutionary state and their central stars in a more unbiased way.

A）由于许多大质量恒星，未演化的星系应该具有低质量、低金属丰度和强而硬的辐射场。因此，它们应该发射强紫外连续谱和极强的发射线。在高红移下，这些矮星系非常难以研究，因此我们需要良好的代理来更详细地研究所涉及的过程。这种极端发射线星系和极蓝色星系即使在低红纬度下也存在，并且易于显示He II发射线，需要由非常大质量、低金属丰度的旋转恒星提供的硬辐射场。 z~7星系中星云CIII]和CIV发射线的发现进一步强调了出现这种发射线所需的硬辐射场的性质问题。由于不仅质量非常大、金属丰度较低的恒星，而且质量巨大的 X 射线双星、吸积的超大质量黑洞，甚至冲击波都可能是硬连续谱光子的来源，因此必须定义一组非常局部的代理，其中空间分辨率和灵敏度允许对气体和单个电离源进行详细研究。另一类有趣的极端发射线星系是绿豌豆，具有极强 [OIII] 线的发射线星系。这些星系似乎为莱曼连续谱辐射的逃逸提供了良好的条件。我们在 LBT 的 3 个观测项目中研究了所有 3 类有希望的高红移（原）星系代理。 B) 盘状星系中流出物和扩散电离气晕的电离过程仍然是一个谜。虽然与恒星形成活动的联系似乎已经很明确（但尚未完全理解），但观察到的电离气体的电离机制仍不清楚：虽然光电离肯定有所贡献，但观察到的线比及其随距盘距离的变化需要改变光子场以及存在额外的目前未知的加热机制。 C) 斯皮策和赫歇尔揭示了银河系中的许多小气泡。在一些情况下，可以获取明显中心恒星的光谱，令人惊讶的是，这些恒星常常被证明是演化的大质量恒星（沃尔夫-拉叶星、发光蓝变星的候选星和OB超巨星）。我们用 LUCI 近红外光谱仪瞄准气泡及其中心恒星，对气泡的高度吸收部分进行分类，并以更公正的方式研究它们的演化状态及其中心恒星。