Spitzer 70/160 μm observations of high-redshift ULIRGs and HyLIRGs in the Boötes field

Abstract

We present new 70 and 160 μm observations of a sample of extremely red (R-[24] ≳ 15 mag), mid-infrared bright, high-redshift (1.7 ≲ z ≲ 2.8) galaxies. All targets detected in the far-infrared exhibit rising spectral energy distributions (SEDs) consistent with dust emission from obscured active galactic nuclei (AGNs) and/or star-forming regions in luminous IR galaxies (LIRGs). We find that the SEDs of the high-redshift sources are more similar to canonical AGN-dominated local ultraluminous IR galaxies (ULIRGs) with significant warm dust components than to typical local star-forming ULIRGs. The inferred IR (8-1000 μm) bolometric luminosities are found to be L bol 4 × 1012 L to3 × 1013 L (ULIRGs/hyper-luminous IR galaxies (HyLIRGs)), representing the first robust constraints on L bol for this class of object. © 2009. The American Astronomical Society. All rights reserved..