A new, purely photometric method for determination of resonance locations in spiral galaxies

TL;DR

This paper introduces a novel photometric technique to determine resonance locations in spiral galaxies, enabling measurements even for distant galaxies up to redshift 0.9, and shows good agreement with existing methods.

Contribution

The paper presents a new purely photometric method for estimating corotation radii in spiral galaxies, applicable to distant galaxies and requiring only photometric data.

Findings

The method yields corotation radii consistent with previous measurements.

It successfully measures resonance locations in galaxies up to redshift 0.9.

The approach can be used for galaxies with measurable spiral arms at large distances.

Abstract

The knowledge of the positions of the corotation resonance in spiral arms is a key way to estimate their pattern speed, which is a fundamental parameter determining the galaxy dynamics. Various methods for its estimation have been developed, but they all demonstrate certain limitations and a lack of agreement with each other. Here, we present a new method for estimating the corotation radius. This method takes into account the shape of the profile across the arm and its width and, thus, only photometric data is needed. The significance of the method is that it can potentially be used for the farthest galaxies with measurable spiral arms. We apply it to a sample of local galaxies from Savchenko et al. and compare the obtained corotation radii with those previously measured in the literature by other methods. Our results are in good agreement with the literature. We also apply the new method to distant galaxies from the COSMOS field. For the first time, corotation locations for galaxies with photometric redshifts up to $z\sim0.9$ are measured.