Luminosity function of high-z object candidates at the epoch of reionization (z approx. > 6) in cosmic evolution survey (COSMOS) field

摘要

The investigation of the luminosity functions (LF) of objects at the epoch of reionization or EoR (z approx. > 6) is crucial for placing stronger constraints on the contribution of different ionizing photon sources. In this study, we aim to estimate the luminosity functions of z approx. > 6 candidates. The data catalog obtained from Hyper Suprime-Cam Strategic Program (HSC-SSP) ultra-deep survey data released one and the ultra-deep Visible and Infrared Survey Telescope for Astronomy (UltraVISTA) data released four in optical (rizy) and near-infrared (YJHK_s) photometry filters, respectively. We focus the deep survey on Cosmic Evolution Survey (COSMOS) field, centered at RA ～ 10~h00~m28.6~s DEC ～ +2°12'21.0''. The 79 candidates are selected by the Lyman Break Galaxies (LBGs) technique with z band drop-out, and photometric redshift approximation (photo-z). We then used the candidates to calculate the z approx. > 6 LF. Accordingly, we compare the LF with other works that focus on the high-z objects at similar z-range.