Dependence of Spiral Winding on Bulge Size in Spirals with Different Stellar Masses and Colors

In the classic Hubble spiral sequence, it is implicitly assumed that spiral arm windiness correlates with bulge size, such that spiral galaxies with larger bulges have more tightly wound spiral arms. We use crowd-sourced galaxy morphologies from Galaxy Zoo participants alongside measurements from the NASA Sloan Atlas (NSA) catalog to explore the impact of different galaxy properties upon the correlation between arm windiness and bulge size. Selecting a low redshift volume limited subset of galaxies with observable spiral arms, we have a total sample of 7,982 galaxies. We observe that the correlation between arm windiness and bulge size shows a significant stellar mass and color dependence. While the correlation is negligible for the entire data sample (as reported in Masters et al. 2019), a positive correlation becomes evident for subsets of bluer galaxies and the correlation becomes negative for subsets of redder galaxies. More massive galaxies also tend to have a negative correlation — among the most massive, reddest spiral galaxies, we find increasingly tightly wound arms for decreasing bulge size.