The formation of the Galactic bulge in an inside-out scenario

TL;DR

This study uses chemical evolution models to explore the inside-out formation of the Milky Way's bulge, analyzing metallicity distributions across different regions to understand its formation history.

Contribution

It introduces a detailed chemical evolution model for the Galactic bulge with radial resolution, providing new insights into its metallicity gradient and formation scenario.

Findings

Inner bulge regions have higher metallicity distributions.

Outer regions show a broader metallicity range with both metal-rich and metal-poor components.

Results support an inside-out formation scenario for the bulge.

Abstract

Chemical evolution models (CEM) are important tools to understand the formation and evolution of the components of the Milky Way Galaxy and other galaxies in the universe. The Galactic bulge is the only galaxy bulge that can be resolved and can be studied with exquisite details. In this way, the bulge metallicity distribution function (MDF) can be traced for different regions within the bulge and can give us clues about the bulge formation scenario. In this work we have assumed an inside-out formation for the Galactic bulge and using a CEM we were able to compute the chemical evolution in nine different radial regions, from 0 to 2 kpc, in steps of 0.25 kpc . The preliminary results show that in the inner regions of the bulge the MDF is skewed to higher metallicities, while at the outer regions there is a metal rich component but also a metal poor component much more extended than in the inner regions. These results may explain the metallicity gradient observed in the Galactic bulge.