Subaru Deep Survey. V. A Census of Lyman Break Galaxies at z ≃ 4 and 5 in the Subaru Deep Fields: Photometric Properties

Abstract

We investigate the photometric properties of Lyman break galaxies (LBGs) at z = 3.5-5.2 based on large samples of 2600 LBGs detected in deep (i′ ≲ 27) and wide-field (1200 arcmin2) images taken in the Subaru Deep Field (SDF) and the Subaru/XMM-Newton Deep Field (SXDF) using broadband B, V, R, i′, and z′ filters. The selection criteria for the LBG samples are examined with 85 spectroscopically identified objects, and the completeness and contamination of the samples are estimated from Monte Carlo simulations based on a photometric-redshift catalog of the Hubble Deep Field-North. We find that these LBG samples are nearly rest-frame UV magnitude-limited samples, missing systematically only 10% of red high-z galaxies (in number), which are a dusty population with E(B - V) ≲ 0.4. We calculate luminosity functions (LFs) of the LBGs with the estimated completeness and contamination and find (1) that the number density of bright galaxies (M1700 < -22 ; corresponding to SFR ≲ 100 h70-2 M⊙ yr-1 with extinction correction) decreases significantly from z = 4 to 5 and (2) that the faint-end slope of the LFs of LBGs may become steeper toward higher redshifts. We estimate the dust extinction of z ≃ 4 LBGs with M