INvestigating Stellar Populations In RElics (INSPIRE)

研究遗迹中的恒星种群（INSPIRE）

• 批准号: ST/X002675/1
• 负责人: Chiara Spiniello
• 金额: $ 83.04万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FX002675%2F1
• 关键词: INvestigating; Stellar; Populations; RElics; INSPIRE

Investigate Stellar Populations In Relics (INSPIRE) is a revolutionary way to understand the early assembly of the most massive galaxies in the Universe, giant ellipticals. This is very important since this family of objects contains more than half of the stars and the majority of the chemical elements in our Universe. Massive ellipticals are believed to form through a two-phase process. At the early times of the Universe's life, an intense, short-lived star formation episode creates compact and massive objects ("red nuggets"). Then, during a second, more time-extended phase, red nuggets merge with other galaxies or gas falls into them and forms new stars. This causes a dramatic growth in size and transforms red nuggets into the massive, giant elliptical galaxies we observe today. Unfortunately, in local ellipticals this secondary "accreted" material contaminates the "pristine" component that encodes the information about the first phases of the mass assembly. This irremediably prevents us from investigating on the very early stages of structure formation in the Universe. Luckily, some red nuggets do not coalesce with any other structure in their lifetime and so continue on their isolated path over cosmic time without increasing in size or, importantly, without changing their stellar content. These lonely red nuggets are up to 6 times smaller in size and 100 times denser than local ellipticals. They are frozen in time and are therefore called "relics" of the ancient Universe; studying them is akin to an archaeologist learning from dinosaur fossils. Relics contain the oldest stars and hence have the potential to unlock our understanding of the very early formation of structures within our Universe. But how many relics exist at each epoch? How could they passively evolve through cosmic time without experiencing any interaction with other systems? And in which kind of environment are they preferentially found? These questions are at the core of my successful research proposal, which uses the forefront facilities of the European Southern Observatory. From high-quality spectra already available on the largest sample of ultra-compact massive galaxies, I will measure their ages to confirm them as relics as old as the Universe. I will fully characterise the stars in these systems, to reveal how relics originally formed and how they have changed since, if at all.Since relics are the "seeds" of local giant ellipticals, my investigation will revolutionise our understanding of the processes driving the initial assembly of the most massive galaxies in the present-day Universe. Matching the INSPIRE data to data from publicly available wide field sky surveys, I will be able study in detail the environment in which relics are preferentially found. This is crucial to understanding how the densest and most compact objects in the Universe form and how they could evolve into local ellipticals. I will also compare my observational results with computer simulations of the entire Universe. The number of relics at each epoch and their characteristics predicted by simulations depend on the ingredients that they use to reproduce the size growth of galaxies (e.g. the number of interactions with other objects that a given galaxy undergoes). Finally, thanks to new imaging and spectroscopy data with the highest spatial resolution reachable from the ground, which will be delivered next year, I will be able to resolve the internal structure of a sub-sample of relics. I will trace the spatial distribution of the stars within the relics and whether they rotate in a disk-like structure, as predicted by some theoretical models. I will build a dynamical model of relics' light profiles, in order to indirectly constrain the characteristics of the dark matter halos in which the densest objects in the Universe are embedded.

INSPIRE是一种革命性的方式来了解宇宙中最大星系的早期组装，巨型椭圆星系。这是非常重要的，因为这个天体家族包含了我们宇宙中一半以上的恒星和大多数化学元素。大质量椭圆星系被认为是通过两个阶段的过程形成的。在宇宙生命的早期，一个强烈的、短暂的星星形成过程产生了紧凑而巨大的物体（“红块”）。然后，在第二个更长时间的阶段，红块与其他星系合并，或者气体福尔斯落入其中，形成新的恒星。这导致了体积的急剧增长，并将红块转变为我们今天观察到的巨大的椭圆星系。不幸的是，在局部椭圆星系中，这种二次“吸积”物质污染了编码质量组装第一阶段信息的“原始”成分。这无可挽回地阻止了我们对宇宙结构形成的早期阶段的研究。幸运的是，一些红块在其一生中不会与任何其他结构合并，因此在宇宙时间内继续其孤立的路径，而不会增加尺寸，或者重要的是，不会改变其恒星内容。这些孤独的红块体的尺寸比当地的椭圆星系小6倍，密度是当地椭圆星系的100倍。它们被冻结在时间中，因此被称为古代宇宙的“遗迹”;研究它们类似于考古学家从恐龙化石中学习。遗迹包含最古老的恒星，因此有可能解开我们对宇宙中结构早期形成的理解。但是每个时代有多少遗迹存在呢？它们怎么可能在宇宙时间中被动地进化，而不经历与其他系统的任何相互作用？它们最容易在什么样的环境中被发现？这些问题是我成功的研究方案的核心，该方案使用了欧洲南方天文台的前沿设施。从超紧凑大质量星系的最大样本上已经获得的高质量光谱中，我将测量它们的年龄，以确认它们是和宇宙一样古老的遗迹。我将对这些星系中的恒星进行全面的观测，以揭示遗迹最初是如何形成的，以及它们此后是如何变化的（如果有的话）。由于遗迹是局部巨型椭圆星系的“种子”，我的研究将彻底改变我们对驱动当今宇宙中最大质量星系初始组装过程的理解。将INSPIRE数据与公开的大视场巡天数据相匹配，我将能够详细研究遗迹优先被发现的环境，这对于理解宇宙中致密和最致密的天体如何形成以及它们如何演变成局部椭圆星系至关重要。我还将把我的观测结果与整个宇宙的计算机模拟进行比较。每个时期遗迹的数量和模拟预测的特征取决于它们用来重现星系大小增长的成分（例如，给定星系与其他物体相互作用的次数）。最后，由于新的成像和光谱数据具有最高的空间分辨率，从地面上可以达到，这将是明年交付，我将能够解决一个子样本的文物的内部结构。我将追踪遗迹中恒星的空间分布，以及它们是否像一些理论模型预测的那样以盘状结构旋转。我将建立遗迹光剖面的动力学模型，以间接约束宇宙中最致密物体所嵌入的暗物质晕的特征。