The impact of strong gravitational lensing on observed Lyman-break galaxy numbers at 4 ≤ z ≤ 8 in the GOODS and the XDF blank fields

Abstract

Detections of Lyman-break galaxies (LBGs) at high-redshift are affected by gravitational lensing induced by foreground deflectors not only in galaxy clusters, but also in blank fields. We quantify the impact of strong magnification in the samples of B435, V606, i775 and z850 & Y105 dropouts (4 ≤ z ≤ 8) observed in the eXtreme Deep Field (XDF) and the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) fields by investigating the proximity of dropouts to foreground objects. We find that ~6 per cent of bright z ~ 7 LBGs (mH160 2) by foreground objects. This fraction decreases from ~3.5 per cent at z ~ 6 to ~1.5 per cent at z ~ 4. Since the observed fraction of strongly le..