I have a PhD in Astrophysics.
University of Arizona’s PhD Astronomy program is one of the best in the world (easily top 15 in the USA). In fact, it is much, much better than Penn, which is relatively weak in astronomy & astrophysics. If you did well at Arizona and participate in research as an undergraduate, you will be able to go to the best PhD programs out there. Arizona is that respected in astronomy & astrophysics.
There is no difference between “astronomy” and “astrophysics”… historically, “astronomy” used to refer more to observations with telescopes, whereas “astrophysics” was more theoretically focused… but these distinctions are pretty much out of date. No one in the field would make any sort of distinction between the two anymore.