Travel support for two observers to conduct astronomical observations at the LBT during April 2020

为 2020 年 4 月期间两名观察员在 LBT 进行天文观测提供差旅费

• 批准号: 447745156
• 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: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/447745156?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 redshift 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 different 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 additionalcurrently 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 forLuminous 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)未进化的星系应该具有低质量，低金属丰度，并且由于有许多大质量恒星而具有强而硬的辐射场。因此，它们应发出强烈的紫外线连续体和极强的发射线。在高红移的情况下，这些矮星系非常难以研究，所以我们需要好的替代品来更详细地观察所涉及的过程。这种极端的发射线星系和极蓝星系即使在低红移也存在，并且容易显示出He II线发射，需要非常大质量、低金属丰度、旋转恒星所能提供的硬辐射场。在z~7星系中发现的星云CIII和CIV发射线进一步强调了产生这些发射线所需的硬辐射场的性质问题。由于不仅是非常大质量、低金属丰度的恒星，而且还有大质量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体光子的可能来源，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，具有极强的[OIII]线的发射线星系。这些星系似乎为莱曼连续辐射的逃逸提供了良好的条件。我们在LBT的3个不同的观测项目中研究了高红移（原）星系的所有3类有希望的代理。B)盘状星系中流出物和扩散电离气体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很好地建立了（但尚未完全理解），但观测到的电离气体的电离机制仍然不清楚：虽然光电离肯定有贡献，但观测到的线比及其随距离的变化需要光子场的变化以及目前未知的额外加热机制的存在。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，有可能获得明显中心恒星的光谱，令人惊讶的是，这些恒星往往是进化的大质量恒星（沃尔夫-拉叶星，发光蓝变量的候选者，以及OB超巨星）。我们利用LUCI近红外光谱对气泡及其中心恒星进行了分类，对气泡的高吸收部分进行了分类，并以更公正的方式研究了气泡的演化状态及其中心恒星。