X-ray and radio activity of Ly {alpha} emitters

Here, we study the X-ray and radio properties of ~4000 LAEs at 2.2<z<6 from the SC4K survey in the COSMOS field. We detect 254 (6.8 per cent +/- 0.4 per cent) LAEs individually in the X-rays (S/N>3) with an average luminosity of 10^44.31+/-0.01^erg/s and average black hole accretion rate (BHAR) of 0.72+/-0.01M_{sun}_/yr, consistent with moderate to high accreting active galactic nuclei (AGNs).

We detect 120 sources in deep radio data (radio AGN fraction of 3.2 per cent +/- 0.3 per cent). The global AGN fraction (8.6 per cent +/- 0.4 per cent) rises with Ly {alpha} luminosity and declines with increasing redshift. For X-ray-detected LAEs, Ly {alpha} luminosities correlate with the BHARs, suggesting that Ly {alpha} luminosity becomes a BHAR indicator.