Gas and star formation in the extreme environments of starburst galaxies

星暴星系极端环境中的气体和恒星形成

• 批准号: RGPIN-2019-05395
• 负责人: Wilson, Christine
• 金额: $ 3.64万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=763130
• 关键词: Gas; star; formation; extreme; environments

In the universe around us, galaxies are made up of billions of stars, many with planets circling around them. This means that we must first understand how stars form before we can understand the formation of either galaxies or planets. My research program focuses on nearby galaxies that are currently experiencing an intense burst of star formation, turning gas into stars at rates that are 10-100 times faster than the rate in galaxies like our own Milky Way. Specifically, I study the physical properties of the gas that is the fuel for star formation, in order to understand why the star formation in these galaxies has kicked into overdrive. Although these "starburst galaxies" are now relatively rare, these high rates of star formation were normal in the early universe, when young galaxies rich in gas were forming most of the stars we see today. However, because these young galaxies lie at incredibly large distances, even the most powerful telescopes find it extremely difficult to measure the detailed properties that are needed for comparison with simulations of star and galaxy formation. Nearby starburst galaxies provide the opportunity to probe the extreme environments (high densities of gas and star formation) that were common in the early universe, but now on the scales of a few hundred light years that are required to provide strong tests of star formation models. My research team will use data from a powerful radio telescope, the Atacama Large Millimeter/submillimeter Array (ALMA), to attack the problem of star formation in extreme environments along several fronts. (1) We will compare rates of star formation with the amount of available gas to probe the universality of the physics that underpins the empirical "star formation law" that has been established for galaxies like our own Milky Way. (2) We will make the first detailed measurements of the populations of individual giant gas clouds in starburst galaxies. Changes in cloud properties may explain the intense star formation: for example, higher density clouds will collapse faster, which could drive the gas to form stars more rapidly. (3) We will also use these new cloud catalogs to obtain critical calibrations that are needed to turn our radio images of galaxies into accurate measurements of the mass of gas in those galaxies. (4) In the most extreme starburst galaxies in the local universe, galaxies so rich in gas and dust that their centres are completely hidden from view in visible light, we will use rarer molecular isotopes (such as 12C18O instead of 12C16O) to probe how long the starbursts last and what kinds of stars they form. Overall, this program of research will provide a breakthrough in our understanding of star formation in the most extreme environments in the universe today and will have strong impact on our understanding of the main epoch of galaxy formation in early universe.

在我们周围的宇宙中，星系由数十亿颗恒星组成，其中许多恒星周围都有行星。这意味着我们必须首先了解恒星是如何形成的，然后才能了解星系或行星的形成。我的研究项目重点关注附近的星系，这些星系目前正在经历剧烈的恒星形成爆发，将气体转变为恒星的速度比我们银河系等星系的速度快 10 到 100 倍。具体来说，我研究了作为恒星形成燃料的气体的物理特性，以了解为什么这些星系中的恒星形成已经进入超速状态。 尽管这些“星爆星系”现在相对罕见，但这种高恒星形成率在早期宇宙中是正常的，当时富含气体的年轻星系正在形成我们今天看到的大部分恒星。然而，由于这些年轻星系的距离非常远，即使是最强大的望远镜也发现很难测量与恒星和星系形成模拟进行比较所需的详细属性。附近的星暴星系提供了探测早期宇宙中常见的极端环境（高密度气体和恒星形成）的机会，但现在的尺度为数百光年，需要对恒星形成模型进行强有力的测试。我的研究团队将使用来自强大射电望远镜阿塔卡马大型毫米/亚毫米阵列（ALMA）的数据，从多个方面解决极端环境中的恒星形成问题。 (1) 我们将比较恒星形成速率与可用气体量，以探讨物理学的普遍性，该物理学是为银河系等星系建立的经验“恒星形成定律”的基础。 (2) 我们将对星暴星系中单个巨型气体云的数量进行首次详细测量。云特性的变化可以解释剧烈的恒星形成：例如，密度较高的云会塌陷得更快，这可能会推动气体更快地形成恒星。 (3) 我们还将使用这些新的云目录来获得将星系射电图像转化为这些星系中气体质量的精确测量所需的关键校准。 (4) 在当地宇宙中最极端的星暴星系中，这些星系富含气体和尘埃，其中心在可见光下完全隐藏，我们将使用更稀有的分子同位素（例如 12C18O 而不是 12C16O）来探测如何星暴持续多久以及它们形成的恒星类型。 总体而言，该研究计划将为我们对当今宇宙最极端环境中恒星形成的理解提供突破，并将对我们对早期宇宙星系形成的主要时代的理解产生重大影响。