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Article Dans Une Revue The Astrophysical Journal Année : 2006

The Active Galactic Nuclei Contribution to the Mid-Infrared Emission of Luminous Infrared Galaxies

Résumé

We determine the contribution of AGN to the mid-IR emission of luminous infrared galaxies (LIRGs) at z>0.6 by measuring the mid-IR dust continuum slope of 20,039 mid-IR sources. The 24 mum sources are selected from a Spitzer MIPS survey of the NOAO Deep Wide-Field Survey Boötes field and have corresponding 8 mum data from the IRAC Shallow Survey. There is a clear bimodal distribution in the 24 to 8 mum flux ratio. The X-ray-detected sources fall within the peak corresponding to a flat spectrum in nufnu, implying that it is populated by AGN-dominated LIRGs, whereas the peak corresponding to a higher 24 to 8 mum flux ratio is likely due to LIRGs whose IR emission is powered by starbursts. The 24 mum emission is increasingly dominated by AGN at higher 24 mum flux densities (f24): the AGN fraction of the z>0.6 sources increases from 9% at f24~0.35 mJy to 74%+/-20% at f24~3 mJy, in good agreement with model predictions. Deep 24 mum, small-area surveys, like GOODS, will be strongly dominated by starburst galaxies. AGN are responsible for ~3%-7% of the total 24 mum background.

Dates et versions

hal-03797067 , version 1 (04-10-2022)

Identifiants

Citer

Kate Brand, Arjun Dey, Dan W. Weedman, Vandana Desai, E. Le Floc'H, et al.. The Active Galactic Nuclei Contribution to the Mid-Infrared Emission of Luminous Infrared Galaxies. The Astrophysical Journal, 2006, 644, pp.143-147. ⟨10.1086/503416⟩. ⟨hal-03797067⟩
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