CII Emission from High-Redshift Quasars As a Signature of Obscured AGNs

Abstract

We study the relation between the luminosities in the CII line at 158 µ m and in the far infrared (FIR) continuum from quasars observed by ALMA at z ≥ 6 and show that the observed relation is better reproduced with a predominance of radiation from an obscured supermassive black hole than with star formation alone. We found that the locus of points in the “CII/FIR–FIR” plane corresponding to the observed set of quasars could be reproduced in our models with the following types of the central ionizing source: (i) a mildly or slightly obscured SMBH with M • > ∼ 10 8 M (cid:12) and a stellar population with bolometric luminosity L ∗ < 3 L • ; (ii) a highly obscured SMBH with M • ∼ 10 6 − 10 8 M (cid:12) and a massive stellar population with bolometric luminosity L ∗ ∼ 300 L • . The Multifaceted Universe: Theory Observations -