2005PASJ...57..447S

begin{HTML} We report on bright Lyman-break galaxies (LBGs) selected in a 767 arcmin² area of the Subaru Deep Field. The selection was made in the i - z_R versus z_B - z_R plane, where z_B and z_B are new bandpasses with a central wavelength of 8842Å and 9841Å, respectively. We detected 12 LBG candidates down to z_R = 25.4, and calculated the normalization of the rest-frame far-ultraviolet (FUV: ≃1400 Å) luminosity function at M_FUV = -21.6 to be ph(-21.6) = (2.6 ± 0.7) * 10^-5 mag^-1 Mpc^-3. This must be the most reliable measurement ever obtained of the number density of bright z ∼ 6 LBGs, because it is more robust against both contamination and cosmic variance than previous values. The FUV luminosity density contributed from LBGs brighter than M_FUV = -21.3 is (2.8 ± 0.8) * 10²⁴ erg s^-1 Hz^-1 Mpc^-3, which is equivalent to a star-formation rate density of (3.5 ± 1.0) * 10^-4 M_☉ yr^-1 Mpc^-3. We find that the FUV luminosity density of bright galaxies increases by an order of magnitude from z ∼ 6 to ∼ 3, and then drops by 10³ from z ∼ 3 to the present epoch. The evolutionary behavior of bright LBGs resembles that of luminous dusty star-forming galaxies and bright QSOs. The redshift of z ∼ 3 appears to be a remarkable era in the cosmic history when massive galaxies were being intensively formed.