Stellar Populations in Star-forming Galaxies

恒星形成星系中的恒星种群

• 批准号: RGPIN-2020-05490
• 负责人: Robert, Carmelle
• 金额: $ 1.75万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740573
• 关键词: Stellar; Populations; Star; forming; Galaxies

STELLAR POPULATIONS IN STAR-FORMING GALAXIES The morphological and chemical evolution of galaxies is a fascinating subject: how did the Universe transform itself from chaotic and chemically poor material into a wide variety of galaxies with rich chemical elements? During the last decade, this topic has gained even more interests with the development of imaging spectrographs, allowing a better grip on the small-scale physics of star formation in nearby galaxies. The study of stellar populations is an important avenue to answer questions in the field of galaxy evolution: stellar populations, as they sculpt the galaxy appearances, retain the signature of events that have been responsible for their formation and therefore, galaxy evolution. In the past years, my research has mainly focused on the description of young stellar populations in star-forming galaxies. Efforts have been dedicated to the development of SITELLE, an imaging Fourier transform spectrograph in the visible built in Québec, and to the leadership of SIGNALS, an international legacy survey with SITELLE at the Canada-France-Hawaii Telescope. SIGNALS, already underway (2018-2022), will reveal the 3D properties of more than 50 000 HII regions, i.e. ionized gas regions surrounding young star-forming populations, in ~40 nearby galaxies at an average spatial resolution of 20 pc. The proposed research here, while developing tools to identify the HII regions and measure their properties in a systematic way, will be concentrated on the low-metallicity regions in a subsample of SIGNALS irregular galaxies, and on the comparison of the HII region properties in various environments. Among others, detailed luminosity functions are to be drawn. Far-ultraviolet data from YPULS (a UVIT survey of the SIGNALS galaxies, for which I am co-PI) will be part of the analysis in order to get the best parameters for the young populations. This information is an important input for the photoionization codes used to describe the HII regions and to estimate the energy returned into the interstellar medium. In order to rebuild the complete star-formation history of the galaxies, older stellar populations will be studied using various synthesis codes based, for example, on absorption lines spectra with SITELLE. More specific questions to be addressed are related to chemical abundance variations in galaxies, small- and large-scale mixing processes in the interstellar medium, the stellar population initial mass function, and the origin and effect of the diffuse ionized gas on the star-formation rate. The homogeneous and statistically significant database of SIGNALS will lead to original and important publications. Seven students will be involved in this research program. They will work with SITELLE data and more than 60 SIGNALS experts (42% women, with great cultural diversity), a unique opportunity for the students formation and career.

星系的形态和化学演化是一个迷人的主题：宇宙是如何将自己从混乱和化学性质贫乏的物质转变为各种各样的具有丰富化学元素的星系的？在过去的十年中，这个话题已经获得了更多的兴趣与成像光谱仪的发展，允许更好地掌握小尺度物理的星星形成在附近的星系。对恒星族群的研究是回答星系演化领域问题的一个重要途径：恒星族群在塑造星系外观时，保留了导致其形成和星系演化的事件的特征。在过去的几年里，我的研究主要集中在恒星形成星系中年轻恒星种群的描述上。一直致力于发展SITELLE，这是一个在魁北克建造的可见光成像傅里叶变换摄谱仪，并致力于领导SIGNALS，这是一个在加拿大-法国-夏威夷望远镜与SITELLE进行的国际遗产调查。SIGNALS已经在进行中（2018-2022），将揭示超过50，000个HII区域的3D特性，即围绕年轻恒星形成群体的电离气体区域，在大约40个附近星系中，平均空间分辨率为20 pc。这里提出的研究，同时开发工具，以确定HII区域和测量其属性的系统的方式，将集中在低金属丰度区域的子样本的信号不规则星系，并在各种环境中的HII区域属性的比较。除其他外，详细的光度函数将被绘制。来自YPULS的远紫外线数据（对SIGNALS星系的UVIT调查，我是其中的共同PI）将成为分析的一部分，以便为年轻群体获得最佳参数。这一信息是用于描述HII区域和估计返回到星际介质中的能量的光电离代码的重要输入。为了重建星系完整的恒星形成历史，将使用各种基于SITELLE吸收线光谱的合成代码研究较老的恒星种群。更具体的问题是要解决的化学丰度变化在星系中，小规模和大规模的星际介质中的混合过程，恒星人口的初始质量函数，和弥漫电离气体对恒星形成率的起源和影响。SIGNALS数据库的同质性和统计学意义将导致原始和重要的出版物。七名学生将参与这项研究计划。他们将与SITELLE数据和60多名SIGNALS专家（42%女性，具有很大的文化多样性）合作，为学生的形成和职业生涯提供独特的机会。