I only saw that the university offered astronomy, and astrophysics as a graduate major. Is astrophysics an undergraduate major too?
No. And honestly, it’s probably for the better – there’s really no benefit to specializing so early, as astrophysicists tend to need PhDs. On top of that, it’s more common to have a B.S. in physics or astronomy than astrophysics when applying to graduate schools for astrophysics.
Specifically for UW, the astronomy degree has most of the same core requirements that the physics degree has, and the requirements of each count as electives towards the other. It’s very common and easy for people to double-major in physics and astronomy. Both departments are very strong and offer many opportunities for research to undergrads.