Determination of resonance locations in barred spiral galaxies using multiband photometry

TL;DR

This study applies a Fourier transform-based method to determine corotation radii in 57 barred spiral galaxies using multiband photometry, finding most have fast bars and discussing implications for dark matter and spiral structure models.

Contribution

It introduces and applies a Fourier phase crossing method across multiple wavebands to measure corotation radii in a large galaxy sample, validating it against previous measurements.

Findings

Approximately 60% of galaxies have fast bars.

Results are consistent with previous simulation-based measurements.

Implications for dark matter distribution and spiral structure theories.

Abstract

In this paper, we apply a method identified by Puerari & Dottori (1997) to find the corotation radii (CR) in spiral galaxies. We apply our method to 57 galaxies, 17 of which have already have their CR locations determined using other methods. The method we adopted entails taking Fourier transforms along radial cuts in the u, g, r, i, and z wavebands and comparing the phase angles as a function of radius between them. The radius at which the phase angles cross indicates the location of the corotation radius. We then calculated the relative bar pattern speed, $\mathcal{R}$, and classified the bar as "fast", where $\mathcal{R} < 1.4$, slow, where $\mathcal{R} \geq 1.4$, or intermediate, where the errors on $\mathcal{R}$ are consistent with the bar being "slow" or "fast". For the 17 galaxies that had their CR locations previously measured, we found that our results were consistent with the values of $\mathcal{R}$ obtained by the computer simulations of Rautiainen, Salo & Laurikainen (2008). For the larger sample, our results indicate that 34 out of 57 galaxies (~60%) have fast bars. We discuss these results in the context of its implications for dark matter concentrations in disk galaxies. We also discuss these results in the context of different models for spiral structure in disk galaxies.