Passage: Remo Ruffini (born May 17, 1942, La Brigue, Alpes-Maritimes, at that time, Briga Marittima, Italy). He is Director of ICRANet, International Centre for Relativistic Astrophysics Network. Moreover, he is President of the International Centre for Relativistic Astrophysics (ICRA); he initiated the International Relativistic Astrophysics PhD (IRAP PhD), a common graduate school program of several universities and research institutes for the education of theoretical astrophysicists. He is Director of the Erasmus Mundus IRAP PhD program (IRAP Ph D Erasmus Mundus). He has been Professor of Theoretical Physics at the University of Rome "Sapienza" from 1978 to 2012.

Question: The IRAP is a grad school program in what field of study?
theoretical astrophysicists