H2020Индивидуална стипендия2021–2023

GalaxyConnect · Unveiling the properties of the first galaxies through their connection with the intergalactic medium

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2021-07-01 → 2023-06-30
Финансиране от ЕС: 162 806 €
Участници: 1
Схема: MSCA-IF

Линиите свързват координатора с партньорите.

Накратко на български

Връзката между първите галактики и околния ги газов облак се анализира чрез измерване на температурата и химичния състав на газа. Това помага да се разбере как са се формирали първите галактики и как са повлияли на ранната Вселена.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Unveiling the properties of the first galaxies through their connection with the intergalactic medium

Understanding how the first galaxies formed is one of the most important unanswered questions in astronomy. One way of studying the first galaxies is to directly observe the light emitted by the stars and gas they contain. This can be difficult though, as many of the galaxies are very faint. However, galaxies do not grow in isolation, but rather they are surrounded by a cosmic web of gas. Another way we can learn about the first galaxies is by studying this connection between the galaxies and the intergalactic gas. Galaxies can interact with the gas surrounding them in different ways. After the Big Bang, the gas in the cosmic web was cold and neutral until the first galaxies in the Universe formed. Light from the stars formed in these galaxies ionized and heated the cosmic web, in a period known as the epoch of reionization. As well as this, outflows driven by supernovae in the galaxies enriched the cosmic web with elements such as carbon and oxygen. Carefully characterising the properties of the cosmic web in the early Universe can therefore provide insights into the nature of the first galaxies. The cosmic web can be observed as a pattern of absorption features in light coming from distant, luminous sources. By making measurements of the statistics of these absorption features and comparing with statistics derived from cosmological simulations, the ionization state, temperature and chemical composition of the intergalactic gas can be unveiled. A key objective of the GalaxyConnect project was to combine theoretical models and observational data to understand how the cosmic web evolves. As well as this, the light coming from the faintest galaxies can be measured using a technique called intensity mapping. This involves making a map across the sky of gas emission coming from certain elements or molecules. This process relates to another objective of the GalaxyConnect project, which was to understand the emission signature of galaxies into the reionization epoch.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

To understand how the first galaxies formed, we need to characterise their properties. Studying these galaxies directly is challenging, as they are hard to detect in emission. Another way of understanding galaxies in the early Universe is through their interactions with the cosmic web of gas surrounding them, which is observed as absorption lines in the spectra of distant quasars. By studying the ionization state and chemical enrichment of this gas, we can put constraints on theories of galaxy formation. During this fellowship, hosted at the Leibniz-Institut für Astrophysik Potsdam, I will use radiative transfer and hydrodynamic cosmological simulations to model the connection between galaxies and the intergalactic medium (IGM). This research will combine my skills in modelling the IGM with the expertise of my supervisor Prof. Dr. Christoph Pfrommer in the physical processes that drive galaxy outflows. The novel aspect of my work is that I will simultaneously model the evolution of the intergalactic medium on large scales, and the physics driving galaxy formation on smaller scales.In particular, I will focus on modelling metal absorption lines, which are a signature of galactic outflows. Typically, interpreting these metal lines is hard, due to the degeneracy between the ionization state of the gas and its metallicity. I will break that degeneracy by carefully calibrating the ionization state of the simulations against existing data from the Lyman-alpha forest. This will allow me to constrain the efficiency of galactic outflows, and to understand the nature of the galaxies that enriched the IGM with metals. I will construct mock observations from my simulations to make direct comparisons with real data, testing models of galaxy formation and constraining the timing of reionization. My results will be essential for interpreting existing and forthcoming observations, as well as for making predictions for the next generation of 30-metre telescopes.

Оригинален текст от CORDIS (на английски).

Участници

LEIBNIZ-INSTITUT FUR ASTROPHYSIK POTSDAM (AIP) · PotsdamКоординаторГермания