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

(abridged) We investigate photometric properties of Lyman Break Galaxies (LBGs) at z=3. 5-5. 2 based on large samples of 2, 600 LBGs detected in deep (i'~27) and wide-field (1, 200 arcmin²) images taken in the Subaru Deep Field (SDF) and the Subaru/XMM Deep Field (SXDF). The selection criteria for the LBG samples are examined with 85 spectroscopically identified objects and by Monte Carlo simulations. We find in the luminosity functions of LBGs (i) that the number density of bright galaxies (M₁₇₀₀100 Msolar yr^-1) decreases significantly from z=4 to 5 and (ii) that the faint-end slope of the luminosity function may become steeper towards higher redshifts. We estimate dust extinction of z=4 LBGs with M~0. 13.