Gaia constraints on the Galactic thick disc

TL;DR

This paper reviews recent spectroscopic findings on the Galactic thick disc and discusses how Gaia data will help understand its formation, chemo-dynamical properties, and the role of mergers and radial migration.

Contribution

It summarizes recent spectroscopic results and highlights open questions about the thick disc that Gaia data can help address.

Findings

Spectroscopic data provide insights into the chemo-dynamical properties of the thick disc.

Open questions remain about the total accreted mass from satellite mergers.

Radial migration's role in thick disc formation is still uncertain.

Abstract

The Gaia mission, with its unprecedented astrometric and photometric precision, combined with its Radial Velocity Spectrometer, will provide to the astronomical community a wealth of necessary constraints to disentangle between the different formation scenarios of the Galactic thick disc. The aim of this review is to present some of the recent results obtained spectroscopically concerning this Galactic structure, and highlight the open questions that still remain to be answered under the Gaia era. These concern mainly the measurement of the chemo-dynamical properties of the Milky Way at the inner and outer parts, which allow us to determine the total accreted mass from the mergers with satellite galaxies, and will give us an estimate of the strength of the radial migration phenomena to form such a structure.