Chemical evolution of the galactic bulge: single and double infall models

TL;DR

This study evaluates various chemical evolution models of the galactic bulge, demonstrating that a multizone, double-infall model best fits observational data involving multiple chemical elements.

Contribution

It introduces and compares one-zone and multizone models with single and double infall scenarios using extensive chemical element constraints.

Findings

Multizone, double-infall models best fit the observational data.

Single-infall models reproduce only some data aspects.

Using multiple chemical elements improves model constraints.

Abstract

Recent work has produced a wealth of data concerning the chemical evolution of the galactic bulge, both for stars and nebulae. Present theoretical models generally adopt a limited range of such constraints, frequently using a single chemical element (usually iron), which is not enough to describe it unambiguously. In this work, we take into account constraints involving as many chemical elements as possible, basically obtained from bulge nebulae and stars. Our main goal is to show that different scenarios can describe, at least partially, the abundance distribution and several distance-independent correlationss for these objects. Three classes of models were developed. The first is a one-zone, single-infall model, the second is a one-zone, double-infall model and the third is a multizone, double infall model. We show that a one-zone model with a single infall episode is able to reproduce some of the observational data, but the best results are achieved using a multizone, double infall model.