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Kazuhiro Shimasaku, Masami Ouchi, Hisanori Furusawa, Makiko Yoshida, Nobunari Kashikawa, Sadanori Okamura, Number Density of Bright Lyman-Break Galaxies at z ∼ 6 in the Subaru Deep Field , Publications of the Astronomical Society of Japan, Volume 57, Issue 3, 25 June 2005, Pages 447–458, https://doi.org/10.1093/pasj/57.3.447
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Abstract
We report on bright Lyman-break galaxies (LBGs) selected in a |$767 \,\mathrm{arcmin}^2$| area of the Subaru Deep Field. The selection was made in the |$i-z_{\mathrm{R}}$| versus |$z_{\mathrm{B}}-z_{\mathrm{R}}$| plane, where |$z_{\mathrm{B}}$| and |$z_{\mathrm{R}}$| are new bandpasses with a central wavelength of 8842 Å and 9841 Å, respectively. We detected 12 LBG candidates down to |$z_{\mathrm{R}} = 25.4$|, and calculated the normalization of the rest-frame far-ultraviolet (FUV: |$\simeq 1400 \,{Å}$|) luminosity function at |$M_{\mathrm{FUV}} =-21.6$| to be |$\phi(-21.6) = (2.6 \pm 0.7) \times 10^{-5} \,\mathrm{mag}^{-1} \,\mathrm{Mpc}^{-3}$|. This must be the most reliable measurement ever obtained of the number density of bright |$z\sim 6$| LBGs, because it is more robust against both contamination and cosmic variance than previous values. The FUV luminosity density contributed from LBGs brighter than |$M_{\mathrm{FUV}} =-21.3$| is |$(2.8 \pm 0.8) \times 10^{24} \,\mathrm{erg} \,\mathrm{s}^{-1} \,\mathrm{Hz}^{-1} \,\mathrm{Mpc}^{-3}$|, which is equivalent to a star-formation rate density of |$(3.5 \pm 1.0) \times 10^{-4} \,{{{M}_{\odot}}} \,\mathrm{yr}^{-1} \,\mathrm{Mpc}^{-3}$|. We find that the FUV luminosity density of bright galaxies increases by an order of magnitude from |$z\sim 6$| to |$\sim 3$|, and then drops by |$10^3$| from |$z \sim 3$| to the present epoch. The evolutionary behavior of bright LBGs resembles that of luminous dusty star-forming galaxies and bright QSOs. The redshift of |$z \sim 3$| appears to be a remarkable era in the cosmic history when massive galaxies were being intensively formed.
