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This study explores the rest-frame luminosity functions of a deep K’-selected galaxy sample in the Subaru Deep Field. The study uses photo-z to determine the best-fit SED template for each galaxy, allowing for analysis of the rest-frame luminosity at any redshift and rest-wavelength. The results indicate no evolution up to z=2.5 and suggest that old stellar populations were already in place by z=2-3. The study also examines the evolution of the rest-UV-K’ color and star formation rate density.
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Rest-frame Luminosity Functions Based on The K’-Selected Galaxy Sample on The Subaru Deep Field Nobunari Kashikawa （National Astronomical Observatory of Japan） appeared in Kashikawa et al., AJ, 125, 53, 2003
Introduction • Approach to explore the rest luminosity functions • photo-z → the best-fit SED template for each sample galaxy → the rest-frame luminosity at any z and at any rest-wavelength → less precise but deeper than spectroscopic sample • Deep K’-selected sample • K’-band → less sensitive to extinction, k-correction, current star-formation & tracing the rest-λ longer than age-sensitive spectral break at 4000Å • Subaru Deep Field (SDF) • 2’×2’ very deep (K’<25.5) K’-band imaged area • B<28.08, V<26.28, R<27.88, I<25.93, z’<24.27, J<25.5 (Vega, 5σ) • In this study, 439 galaxy sample with K’<24 • we are now conducting a deep (R<28) and wide (34’×27’) follow-up optical imaging
Rest-K’ LF • no evolution up to z=2.5 • old stellar population was already in place by z=2-3 ⇔Papovich et al. (2002) from stellar-mass estimate “massive present-day galaxies were not fully assembled by z=2.5” • save the hierarchical model if “M/LK decreases with z” (Drory et al. 2002 for z<1.2) No number evolution for LK selected galaxies Decreases with z for M selected galaxies • Bolzonella et al. (2003) no evolution of rest-Ks LF up to z=2 →consistent with our study
Rest-UV(2000A) LF • consistent with • Cowie et al. (1999) @z<1.5 and • Steidel et al. (1999) @z=3 • strong evolution (1.0mag brighter) • up to z=3.5 • shallow faint end slope @z=3 • The rest-B LF shows mild brightening with epoch up to z=2.5
Evolution of Rest UV-K’ color • bluing trend@z<1 at any abs. mags. • flat@z>1 • →subsequent SF • by merging @1<z<3 • more massivegalaxies (luminous in K’) are redder at every epoch
Star Formation Rate Density • rest UV-LF → SFRD • broadly consistent with previous results @z<1.5 • show slight deficiencies @z>1.5 • ← due to the shallower faint- • end slope of our UV-LF • If the slope of the rest UV-LF @ z=3 is really as steep as α=-1.6, our K’-selected sample contributes only 42% of the total UV luminosity density @ z=3 • 58%… • →faint blue galaxies @z>3？ • but uncertainty is large
N(z) on SDF • Kauffman&Charlot(1988) test for PLE vs. hierarchical model • consistent with previous obs. on K<21 • first time to derive N(z) down to K=24 • models － taking account of selection function of SDF & dust extinction • consistent with PLE on reliable mag. range 22<K<23 • hierarchical model shows an apparent deficiency at z>2 • KS-test also supports that PLE agree with obs. • The N(z) of FIRES (Daddi et al. in this proceedings) down to K=24 is consistent with our study.
Subaru Deep Field Project • On-going Subaru Observatory Project to search high-z (4<z<7) populations. • Survey: 34’x27’ wide FOV of Suprime-Cam • z’<26.5 (9.3hr exp.) NB921(14.0hr exp.) • i’<27.1 (11.0hr exp.) NB816(12.0hr exp.) • R<27.5 (10.2hr exp.) • B<27.8 (11.25 exp.) • Follow-up spectroscopy & NIR imaging • Discovery of two z=6.6 Lyman-alpha emitters (Kodaira et al. 2003)
