Identifying Lyman Alpha Emitters powered by AGNs

Abstract

Lyman Alpha Emitters (LAEs) are usually thought to be powered by star formation. It has been recently reported that a fraction of LAEs at redshift z~3-4 hosts an Active Galactic Nuclei (AGN). If an AGN is present it could be obscured and undetectable in X-rays, but yet dominate the Lya luminosity. We examine the properties of these AGN-powered LAEs at high redshift (z>=6) using radiative transfer cosmological simulations and obtain a reliable criterion to identify them from their observed \Lya line and surface brightness. We find that these sources should have: (a) negative line weighted skewness, S_w <0, and (b) surface brightness profiles FWHM >= 1.5". This parameter space cannot be populated by starburst LAEs. Thus, LAEs satisfying this criterion would be strong candidates for the presence of a hidden AGN powering their luminosity.

6 pages, 5 figures, accepted for publication by MNRASL

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• Ab Initio Cosmological Simulations of CR7 as an Active Black Hole
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