The assembly history of the milky way and nearby galaxies through s-plus' wide field photometry

• Grant number: 24/02676-6
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: March 01, 2024
• End date: November 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Claudia Lucia Mendes de Oliveira
• Grantee: Guilherme Fabricio Bolutavicius
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 11/51680-6 - Exploring the universe: from the galaxies formation to Earth-like planets with the Giant Magellan Telescope, AP.ESP

Abstract

The lambda-Cold Dark Matter (lambda-CDM) cosmological model predicts a hierarchical formation process of the structures present in the universe, in such a way that galaxies like ours must have started their histories much smaller than they are today but were then formed through cannibalization of lower mass systems. With the advent of the Gaia survey, especially, more recently, its 3rd data release, we have very precise data on the kinematics of a large number of stars. Thus, in recent years, much progress has been made in the study of accreted stellar populations in our Galaxy, mainly in the halo close to the sun, and, consequently, the formation history of the Milky Way through its mergers has increasingly been understood. The first stage of this work is based on trying to characterize chemo-dynamically these halo substructures, to better understand their origins and intrinsic relationships. This can be done using photometric data like that from S-PLUS, having in mind a method to obtain metallicities for these stars, e.g. with machine learning. The great advantage of using photometric data is basically statistical, since with photometry it is possible to observe many more stars in much less time, therefore resulting in a more significant sample. Since the formation process of our Galaxy should not be unique, we also plan to study some nearby galaxies (d r 30 Mpc), but outside the Local Group, such as the Sculptor galaxy, Centaurs A and other galaxies of interest, e.g. CLoGS members. In these cases, as they are too far away for us to use individual stars, we plan on using globular clusters, as they are bright enough to be detected even outside the local group and have the advantage of being simple stellar populations, and therefore easier to model. For this, we will adapt the method of Buzzo et al. (2022) to detect globular cluster candidates in these galaxies and determine relevant parameters such as their distribution of metallicities and possibly also radial velocities. In this way, based on a better characterization of cluster populations in other nearby galaxies, we can analyze the validity of galaxy formation models and better understand the role of the accretion of smaller satellite galaxies, and mergers in general, in this process. (AU)