Cosmological as an adjective is of or pertaining to cosmology, or to the overall structure of the universe while Astrophysics as a noun is the branch of astronomy or physics that deals with the physical properties of celestial bodies and with the interaction between matter and radiation in celestial bodies and in the space between them.
Part of speech: adjective
Definition: Of or pertaining to cosmology, or to the overall structure of the universe
Part of speech: noun
Definition: The branch of astronomy or physics that deals with the physical properties of celestial bodies and with the interaction between matter and radiation in celestial bodies and in the space between them.
We hope you now know whether to use Cosmological or Astrophysics in your sentence.