Catechism of the Catholic Church §627 — excerpt
Christ's death was a real death in that it put an end to his earthly human existence. But because of the union his body retained with the person of the Son, his was not a mortal corpse like others, for "divine power preserved Christ's body from corruption."
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: St. Thomas Aquinas, STh III, 51, 3