They're totally authentic cultures. How would they not be?
Well, Heavy Metal as a genre is not considered to be a legitimate subculture because of it's commercial status and audience of working-class males. It is written off in the literature as having no meaning and being devoid of any political or social importance.
I can finde hundreds of peer-reviewed journal articcles on Punk and Hip-Hop. I've found two on Heavy Metal, and one of them is utterly dismissive.

