Galactic halo structures with blue horizontal-branch stars

• Grant number: 22/16502-4
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: April 01, 2023
• End date: March 31, 2027
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Silvia Cristina Fernandes Rossi
• Grantee: Fabrícia Oliveira Barbosa
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The Milky Way hierarchical formation scenario is currently supported by the detection of numerous substructures resulting from accretion events. With the advent of Gaia astrometry, combined with high-precision spectroscopic data, we have confirmed that the inner part of the halo is dominated by an accreted dwarf galaxy, Gaia-Sausage/Enceladus, in addition to the detection of many other stellar streams and overdensities. In this project, we aim to explore these structures found in the Galactic halo, using available kinematic data and inferred ages for blue horizontal-branch stars. This information allows us to investigate the relationships between the chronology and the kinematics of the individual structures and the entire stellar halo and compare them with the results obtained with simulations. Furthermore, current knowledge of the halo composition can be used to study the problem concerning the morphology of the horizontal branches of globular clusters. For this purpose, we must unite the chemical abundances and the orbital properties, which inform about the origins of the clusters. With this, we aim to know more about the formation history of the Galaxy, contributing to the studies of its structures, and possibly to the understanding of the nature of post-main sequence stages of stars.