I think that [1] is the paper that this is based on. I don't work on dynamics and I found it pretty readable. Most of what is in the article is in sections 3.2, section 4 (discussion) and section 5 (conclusions).<p>[1] <a href="https://arxiv.org/pdf/1904.11436.pdf" rel="nofollow">https://arxiv.org/pdf/1904.11436.pdf</a>
Huh.<p>I thought that there was a solid theoretical basis for the density wave hypothesis. But TFA implies that the main constraint was consistency with the Hubble tuning fork diagram.<p>That would be funny, because I've never really understood the density wave hypothesis.
The Hubble fork isn't "wrong". It's just a classification scheme. The fork has nothing to do with how spiral structures form or how long they last, it's just a way to quickly describe them.
Given that most cosmology relies on a huge percentage of dark matter, which cannot be detected, and a huge amount of dark energy, with enormous conflicting calculations, I think it's fair to say that astronomers are wrong about a lot of things.