Active Galactic Nuclei in Ultraluminous Infrared Galaxies

Eleonora Sani, Guido Risaliti

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We present L/M band spectra of 5 bright ULIRGs at low z. These data, obtained with ISAAC at VLT, allow a detailed study of the physical properties of AGNs in ULIRGs. We distinguish 2 classes of sources: ULIRGs hosting an unobscured AGN, and sources with highly obscured AGNs. SB activity is also present in all sources. We discuss the physical properties of the dusty emitters/absorbers, and show that AGNs are dominant in the L-band but their contribution to the bolometric luminosity is small.