Reexamination of the Radial Abundance Gradient Break in NGC 3359

TL;DR

This study reexamines the radial oxygen abundance gradient in galaxy NGC 3359, confirming a significant break near the galaxy's effective radius, which is likely influenced by the galaxy's strong bar structure.

Contribution

It provides new spectroscopic measurements and statistical analysis confirming the presence of a metallicity gradient break in NGC 3359, highlighting the impact of galactic bars on metal distribution.

Findings

Confirmed the metallicity gradient break with high confidence.

Demonstrated the influence of the galaxy's bar on metal distribution.

Validated the use of recent metallicity diagnostics for gradient analysis.

Abstract

In this contribution, we reexamine the radial oxygen abundance gradient in the strongly barred spiral galaxy NGC 3359, for which, using an imaging spectrophotometric technique, Martin & Roy detected a break near the effective radius of the galaxy. We have new emission line flux measurements of HII regions in NGC 3359 from spectra obtained with the Subaru telescope to further investigate this claim. We find that there are small systematic variations in the line ratios determined from narrow-band imaging as compared to our spectroscopic measurements. We derive and apply a correction to the line ratios found by Martin & Roy and statistically examine the validity of the gradient break proposed for NGC 3359 using recently developed metallicity diagnostics. We find that, with a high degree of confidence, a model with a break fits the data significantly better than one without it. This suggests that the presence of a strong bar in spiral galaxies can generate measurable changes in the radial distribution of metals.