Programme by Session

We present the study of ~4000 Lya-alpha emitters (LAE) in the COSMOS field, selected across z=2.2-6 and their black hole activity. We use stacking to probe the X-ray activity of LAEs beyond the detection limits of current X-ray surveys and compare our results with similar analyses done to lower redshift (z=0.4-2.2) H-alpha emitters (HAE). The total AGN fraction (8.5% of LAEs) shows evidence of declining with increasing redshift and of a correlation between the AGN fraction and Ly-alpha luminosity. This behaviour is observed for both Radio and X-ray AGN. X-ray luminosity grows with Ly-alpha luminosity for sources detected directly in the X-ray surveys, suggesting that Ly-alpha is tracing the BHARs of these galaxies. We detect no clear relation of Ly-alpha luminosity with radio luminosity or spectral index. We detect no X-ray emission from the stacking of X-ray undetected LAEs, indicating BHARs of less than 0.08 Msolar/yr, while upper limits from stacking in the Radio and FIR show SFRs comparable to those measured directly from H-alpha and Lyman-alpha line luminosities (SFRs of ~7-20 Msolar/yr). Our results show the BHAR/SFR ratio of SF galaxies follows the evolution of SFRD closely for z=0.4-2.23 but we cannot claim the BHAR of SF galaxies follows SFRD for higher redshifts. Furthermore, comparing our results to our previous study of H-alpha selected galaxies at lower redshifts reveals that our sample has SFRs bellow HAEs and that LAES may have higher black hole-to-galaxy growth ratio than HAEs.