1. 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)

2. 1 – stellar populations of galaxies in high-z groups/clusters 2 – formation timescale of massive cluster ellipticals

3. 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]

4. 1 – A very low-mass group at z=1.61

5. A group of galaxies at z=1.61 in the Chandra Deep Field South Tanaka et al. 2013 PASJ, 65, 17 Psuedo-color image based on ACS/WFC3 images from CANDELS Note that this system is NOT the Kurk+09 system.

6. A group of galaxies at z=1.61 in the Chandra Deep Field South Tanaka et al. 2013 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.

7. 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

8. 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 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%

9. Deep nearIR spectroscopy with MOIRCS 7 hours integration on one of the brightest members... Object spectrum Noise spectrum

10. 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

11. Spectrophotometric fit cD galaxy of the group. Note the large stellar mass. Tanaka et al. in prep.

12. Spectrophotometric fit Tanaka et al. in prep.

13. Compared to the field, galaxies in groups and clusters have -- lower SFRs (this work) -- higher SFRs (Tran+ 2010, Joana’s 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?

14. 2 – A forming cluster at z=2.16

15. PKS1138 at z=2.16 Tanaka, De Breuck, Venemans, Kurk et al. 2010 A&A Koyama et al. 2013 MNRAS, 428, 1551

16. Spectrophotometric fits again... We identified 11 proto-cluster members this way. Tanaka et al. 2013 ApJ, 772, 113

17. Physical properties of the members Quiescent galaxies in the forming system at z=2! Tanaka et al. 2013 ApJ, 772, 113

18. 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. 2013 ApJ, 772, 113

19. 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. 2013 ApJ, 772, 113

20. 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 <~ 0.5 Gyr Affected by systematics in the zero points. tv is forced to be 0 Affected by flux calibration uncertainty Not strongly affected by flux calibration uncertainty

21. Formation timescale Recent numerical simulations of early-type galaxy formation by Johansson et al. (2012) suggest the formation timescale of ~1.5Gyr. Missing ingredients in sims? Or, high density environment is important? Of course the number suffers from uncertainty in SPS models. e-folding timescale of ~1.5Gyr.

22. Hyper Suprime-Cam (HSC) 1.5 deg diameter FoV A 300-night survey with HSC has just started! HSC-Wide: ~26-ish mags in grizy over 1400sqdeg HSC-Deep: ~27-ish mags in grizy plus a few NBs over 28sqdeg HSC-UltraDeep: ~27.5-ish mags in BB and several NBs over 3sqdeg Weak-lensing cosmology, transients, MW and local galaxies, AGNs/QSOs at z>~6, galaxies, clusters, etc, etc. Public data release planned every 1-2 years. So stay tuned!

23. 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. 10-30 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 2”mag. lim. A weather factor is included in the mag limits for D and UD.

24. Target fields Wide : Spring/Autumn equatorial region + HectoMAP region Deep : XMM-LSS, E-COSMOS, ELAIS-N1, DEEP2-F3 UDeep : SXDS (XMM-LSS), COSMOS