The build-up and fate of self-gravitating systems in the Universe

Project Information

THESYS

Grant agreement ID: 895174

DOI

10.3030/895174

Project terminated on 1 November 2023

EC signature date 21 April 2020

Start date 1 September 2021

End date 21 December 2023

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 196 707,84

EU contribution

€ 196 707,84

Coordinated by

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
France

Periodic Reporting for period 1 - THESYS (The build-up and fate of self-gravitating systems in the Universe)

Reporting period: 2021-09-01 to 2023-08-31

Summary of the context and overall objectives of the project

This MSCA action focuses on developing dynamical models to understand the large-scale evolution of disc galaxies and their stellar populations, as well as the dynamics of self-gravitating stellar structures like globular and nuclear star clusters on a parsec scale. This is timely because ongoing and upcoming surveys and instruments like Gaia, Gaia-ESO, APOGEE, GALAH, WEAVE, MOONS, 4MOST, LSST, ELT, and JWST are collecting and will continue gathering an unprecedented amount of information on the chemical composition, age, and phase-space distribution of stellar populations across various Galactic structures such as the Galactic Centre, globular clusters, their streams, and escapees. By combining expertise in dynamical modeling, Galactic dynamics, and stellar populations, this project aims to prepare for fully exploiting the upcoming data releases to reconstruct the dynamical and star formation history of the Milky Way, spanning from its halo to its central nuclear regions. The project's key objectives are 1) using the Galactic globular cluster system history to gain insights on the formation of our Galaxy; 2) understanding how the globular cluster population changed with time to uncover how this impacted the Galactic structures; 3) shedding light on the origin of nuclear star clusters and their links with globular clusters.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

This MSCA action led to multiple complementary projects, all focussed on the modelling of globular and nuclear star cluster formation and evolution in relation to the Galactic history. The analysis of dissipationless N-body simulations conducted during the fellowship challenged assumptions about accreted globular clusters' dynamical coherence and showed significant overlap with in-situ clusters in kinematic spaces, thus impacting the current methods used to reconstruct the Galaxy's accretion history. Another research line focused on modeling the evolution of globular clusters in the Galactic potential using direct and collisional N-body codes, parallelized on graphic processing units. This exploration aimed to investigate the formation of multiple populations in globular clusters and the contributions of these clusters to the field stellar population via escaped stars. Additionally, the project contributed to the modelling of the stellar streams resulting from the disruption of all globular clusters in the Milky Way. Additionally, a new N-body code including an implementation of the dynamical friction effect has been developed to simulate the formation and evolution of nuclear star clusters through the merger of globular clusters, enabling the tracking of their infall to the Galactic centre. Furthermore, galaxy mergers were investigated, resulting in the formation of supermassive black hole binaries, identifying indirect effects of these systems observable in galaxies that recently underwent mergers. Contributions were made to various works on the study of stellar populations at the Galactic Centre, where the researcher’s theoretical and modeling expertise was instrumental in interpreting observational data.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The research has significantly advanced the scientific knowledge on the formation and evolution of Galactic stellar populations. In addition, the project played a crucial role in education, benefiting from the researcher's expertise in outreach and teaching activities. Furthermore, the computational methodologies developed have the potential to lead to innovations in other data-intensive fields, thus contributing to technological progress.

Stellar streams and multiple populations in globular clusters.