On the formation time scale of massive cluster ellipticals based on deep near-IR spectroscopy at z~2 Masayuki Tanaka (NAOJ) Sune Toft (DARK), Alexis Finoguenov (Helsinki), Mohammad Mirkazemi (MPE), Dave Wilman (MPE), John Mulchaey (Carnegie), Ueda Yoshihiro (Kyoto), Yongquan Xue (Penn State), Niel Brandt (Penn State), Danilo Marchesini (Tufts), Andrew Zirm (DARK), Carlos De Breuck (ESO), Tadayuki Kodama (NAOJ), Yusei Koyama (NAOJ), Jaron Kurk (MPE), Ichi Tanaka (NAOJ) 1 stellar populations of galaxies in high-z groups/clusters 2 formation timescale of massive cluster ellipticals Chemical chronometer Alpha elements : primarily released by type-II SNe on a short timescale Fe-peak elements: primarily released by type-Ia SNe on a longer timescale. Nelan et al. 2005, ApJ, 632, 137Thomas et al. 2010, MNRAS, 404, 1775 Some of the major uncertainties include: - delay-time distribution of type-Ia SNe - IMF can also change [alpha/Fe] 1 A very low-mass group at z=1.61 A group of galaxies at z=1.61 in the Chandra Deep Field South Tanaka et al PASJ, 65, 17 Psuedo-color image based on ACS/WFC3 images from CANDELS Note that this system is NOT the Kurk+09 system. A group of galaxies at z=1.61 in the Chandra Deep Field South Tanaka et al PASJ, 65, 17 Psuedo-color image based on ACS/WFC3 images from CANDELS M200 ~ 3x10^13 Msun A progenitor of today's cluster of typical mass Note that this system is NOT the Kurk+09 system. Color-magnitude diagram Photo-z member candidates Mags/Colors are from ACS/WFC3 from CANDELS. Spectroscopically confirmed fg/bg galaxies. Tanaka et al. 2013, PASJ, 65 17 Color-magnitude diagram Photo-z member candidates Mags/Colors are from ACS/WFC3 from CANDELS. Spectroscopically confirmed fg/bg galaxies. Tanaka et al. 2013, PASJ, Surprisingly prominent red sequence! Bright members are almost exclusively red. - No MIPS detection of these red galaxies. - Most of these galaxies are early-type galaxies. - AGN fraction ~ 40% Deep nearIR spectroscopy with MOIRCS 7 hours integration on one of the brightest members... Object spectrum Noise spectrum Deep nearIR spectroscopy with MOIRCS 7 hours integration on one of the brightest members... Binnig helps reduce non-Gaussian noise due to sky residuals. Object spectrum Noise spectrum Spectrophotometric fit cD galaxy of the group. Note the large stellar mass. Tanaka et al. in prep. Spectrophotometric fit Tanaka et al. in prep. Compared to the field, galaxies in groups and clusters have -- lower SFRs (this work) -- higher SFRs (Tran+ 2010, Joanas talk) -- similar SFRs (Ziparo+ 2013) Stellar populations in z~1.5 systems There seems to be a large diversity in galaxy populations in high-z systems We should probably move on to do statistical work. How do we get deep data over a large area? 2 A forming cluster at z=2.16 PKS1138 at z=2.16 Tanaka, De Breuck, Venemans, Kurk et al A&A Koyama et al MNRAS, 428, 1551 Spectrophotometric fits again... We identified 11 proto-cluster members this way. Tanaka et al ApJ, 772, 113 Physical properties of the members Quiescent galaxies in the forming system at z=2! Tanaka et al ApJ, 772, 113 Nascent red sequence A bit busy plot, but the colored objects are likely members. Note that the quiescent galaxies lie on the reddest part of the red sequence. Tanaka et al ApJ, 772, 113 Stacked spectrum of the 4 quiescent galaxies No strong emissoin lines and the galaxies are indeed quiescent. Possible CaIIH+K feature...? Best-fit model spectrum shifted downwards for clarity Atmospheric absorption Tanaka et al ApJ, 772, 113 Constraints on the formation time scale Free parameters are : (1) formation redshift (or age), (2) extinction, (3) star formation time scale (A) Location of the red sequence on a color-magnitude diagram: z_f ~ 4 (assums tau_v=0 and tau=0) (B) Full spectral fitting: (C) Dn4000 (insensitive to dust): tau ~6, galaxies, clusters, etc, etc. Public data release planned every 1-2 years. So stay tuned! Survey strategy HSC-Wide 1400 sq. deg. 10-min in BB HSC-Deep 28 sq. deg. 2-4 hours in BB+NB HSC-Ultra Deep 3.5 sq. deg hours in BB+NB g 10 hours28.1 r 10 hours 27.7 i 20 hours 27.4 z 27 hours26.8 y 27 hours 26.3 g 2 hours27.5 r 2 hours27.1 i 3 hours26.8 z 3 hours26.0 y 3 hours25.3 g 10 min26.7 r 10 min26.2 i 20 min26.0 z 20 min25.2 y 20 min24.4 Filter exp.time 2mag. lim. A weather factor is included in the mag limits for D and UD. Target fields Wide : Spring/Autumn equatorial region + HectoMAP region Deep : XMM-LSS, E-COSMOS, ELAIS-N1, DEEP2-F3 UDeep : SXDS (XMM-LSS), COSMOS