Radial Metallicity Distribution Breaks at Corotation Radius in Spiral Galaxies

TL;DR

This study finds a significant correlation between corotation radii and metallicity gradient breaks in spiral galaxies, supporting the idea that long-lived spiral structures influence star formation and metallicity distribution.

Contribution

It compiles and analyzes data from 27 galaxies to demonstrate the correlation between corotation radii and metallicity gradient breaks, highlighting the role of spiral structure dynamics.

Findings

Most galaxies show metallicity breaks near corotation radius.

A significant correlation exists between corotation radii and metallicity gradient changes.

Results support the influence of long-lived spiral structures on metallicity distribution.

Abstract

We analyzed the relation between the corotation radii and the galactic radii at which breaks or changes of slope of the metallicity gradients occur in spiral galaxies. With this purpose we compiled the results from the literature on rotation curves, corotation radii and radial metallicity distributions of 27 galaxies, of which 16 were considered qualified to be studied in the context of this work. We re-scaled all references of each galaxy to a same framework in order to compare the results and to identify the radii where breaks and changes of slopes are found, when non-linear models fit the radial metallicities better than a linear model. In most galaxies we have found minima and breaks in radial metallicity near the corotation radius, revealing a significant correlation between these two radii, as it occurs in our Galaxy. The results are interpreted as a consequence of long-lived spiral structures, in which the star-formation rate depends on the distance to the corotation radius, producing secular effects in the observed radial metallicity distributions.