Letter to the Editor

Distinguishing AGN from starbursts as the origin of double-peaked Lyman-alpha emitters in the reionization era

¹ Département de Physique Théorique, Université de Genève, 24 quai Ernest-Ansermet, 1211 Genève 4, Switzerland
e-mail: hamsa.padmanabhan@unige.ch
² Astronomy department, Harvard University, 60 Garden Street, Cambridge, MA 02138, USA

Received: 10 December 2020
Accepted: 22 January 2021

Abstract

We discuss the possible origin of the double-peaked profiles recently observed in Lyman-alpha emitters (LAEs) at the epoch of reionization (z  ≳  6.5) from obscured active galactic nuclei (AGN). In combining the extent of the Lyman-α near-zones estimated from the blue peak velocity offset in these galaxies, with the ionizing emissivity of quasars at z ≳ 6, we forecast the intrinsic UV and X-ray luminosities of the AGN needed to give rise to their double-peaked profiles. We also estimate the extent of the obscuration of the AGN by comparing their luminosities to those of similar quasar samples at these epochs. Future X-ray and radio observations, as well as those with the James Webb Space Telescope, will be valuable tools to test the AGN contribution to the intergalactic-scale ionization zones of high-redshift LAEs.