Stellar Populations in the Galactic Center

TL;DR

This paper reviews the stellar populations and star formation rate in the Galactic Center, presenting new distance estimates, analyzing stellar tracers, and discussing metallicity gradients and their implications.

Contribution

It provides a new estimate of the Galactic Center distance and analyzes stellar populations and metallicity gradients using recent observational data.

Findings

New distance modulus estimate: 14.49 mag (7.91 kpc).

Identification of classical Cepheids as key tracers of star formation.

Metallicity gradient shows a sharp change at the inner disk edge.

Abstract

We discuss the stellar content of the Galactic Center, and in particular, recent estimates of the star formation rate (SFR). We discuss pros and cons of the different stellar tracers and focus our attention on the SFR based on the three classical Cepheids recently discovered in the Galactic Center. We also discuss stellar populations in field and cluster stars and present some preliminary results based on near-infrared photometry of a field centered on the young massive cluster Arches. We also provide a new estimate of the true distance modulus to the Galactic Center and we found 14.49$\pm$0.02(standard)$\pm$0.10(systematic) mag (7.91$\pm0.08\pm0.40$ kpc). Current estimate agrees quite well with similar photometric and kinematic distance determinations available in the literature. We also discuss the metallicity gradient of the thin disk and the sharp change in the slope when moving across the edge of the inner disk, the Galactic Bar and the Galactic Center. The difference becomes even more compelling if we take into account that metal abundances are based on young stellar tracers (classical Cepheids, Red Supergiants, Luminous Blue Variables). Finally, we briefly outline the possible mechanisms that might account for current empirical evidence.