2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/13381Many ultraluminous infrared galaxies (ULIRGs) are powered by quasars hidden in the center, but many are also powered by starbursts. A simply diagnostic diagram is proposed that can identify obscured quasars in ULIRGs by their high-ionization emission lines ([O III] 5007/Hbeta >~ 5), and ``warm'' IR color (f_{25}/f_{60} >~ 0.25).2 pages including 2 postscript figures to be published in the proceedings of the IAU Symposium No. 194: "Activity in Galaxies and Related Phenomena", held in Byurakan, Armenia, 17-21 August 1998Astrophysicstext