The AGN/starburst content in high redshift ULIRGs
arXiv:0903.0299 · doi:10.1111/j.1745-3933.2009.00649.x
Abstract
We apply a simple model, tested on local ULIRGs, to disentangle the active galactic nucleus (AGN) and starburst contributions in submillimiter and 24um-selected ULIRGs observed with the Spitzer-IRS spectrometer. We quantitatively estimate the average AGN contribution to the stacked 6-8um rest-frame spectra of these sources in different luminosity and redshift ranges, and, under the assumption of similar infrared-to-bolometric ratios as in local ULIRGs, the relative AGN/starburst contributions to the total infrared luminosity. Though the starburst component is always dominant in submillimeter-selected ULIRGs, we find a significant increase of the AGN contribution at redshift z>2.3 with respect to lower z objects. Finally, we quantitatively confirm that the mid-infrared emission of 24um-selected ULIRGs is dominated by the AGN component, but the starburst component contributes significantly to the bolometric luminosity.
5 pages, 5 figures, 2 tables. Accepted for publication in MNRAS Letters
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- Spitzer's View of the Candidate Cluster and Protocluster Catalog (CCPC)