more:
THE FOLLOWING ARTICLE IS OPEN ACCESS
A Kiloparsec-scale Molecular Wave in the Inner Galaxy: Feather of the Milky Way? [with footnotes]
https://iopscience.iop.org/article/10.3847/2041-8213/ac341f
from the above article, “feathers are common in prototypical Sc galaxies as well as in Sb galaxies.”
Is the Milky Way a Sb or Sc galaxy?
I live here, so, SC...