Galaxy Evolution and WFMOS History of Galaxies Present-day Universe: SDSS WFMOS Survey of z>1 Universe K. Shimasaku (University of Tokyo)

Star Formation Rate Density [Msun/yr/Mpc3] History of Galaxies：Current Understanding redshift peak monotonic decrease Star Formation Rate Density [Msun/yr/Mpc3] first galaxies (z～30?) galaxy morphology galaxy clusters reionization (z～10?) birth of Earth now Age of Uniserve (x10 yr) 8

z=7.0 For high-z universes, our knowledge is limited to average (and limited) properties of bright galaxies.

In the present-day universe, galaxy properties depend strongly on mass and environment. Specific SFR vs Stellar Mass for z=0 Galaxies spiral Specific SFR [/Gyr] dwarf E, S0 Stellar Mass [Msun] Brinchmann et al. 2004 (SDSS)

Theory also predicts that galaxy evolution depends on mass and environment. ΛCDM model = Λ＋cold dark matter ＋ baryon ＋ primordial fluctuations primordial fluctuations hierarchical growth to more massive galaxies complex baryon processes depending on mass, environment, and time gas cooling and star formation feedback to gas SN heating → effective in less massive galaxies AGN heating → effective in massive galaxies environmental effect (galaxies, ICM, UV background…) galaxy feedback gas star cooling environment ・these processes have not been solved ・may be missing some important processes

Sloan Digital Sky Survey: A definitive data set for the present-day universe 2.5m survey telescope mosaic CCD camera multifiber spectrograph - very wide field : πsteradian (1x10^8 Mpc for z<0.1) - rich photometry : 5 bands (ugriz) - huge number of spectra : 10^6 galaxies, 10^5 QSOs 3

Next Step: SDSS-like Survey for z>1 Universe Major Science Goal: Derive fundamental properties like age, SFR, metallicity, dust extinction, morphology, internal structure, QSO/AGN, SMBH as functions of redshift, environment, and galaxy mass At z>1 spectroscopic data are much poorer than imaging data (cf. CfA vs SDSS for z～0 universe). Photometric redshift cannot be a substitute for spectroscopy. WFMOS can contribute to the above science, if excellent imaging data pre-exist.

What can WFMOS do? WFMOS performance comoving length - wide FoV: 1.77 deg2 - high multiplicity: 4500obj/FoV - high spec resolution: R=3000-40000 - high sensitivity around 1um For a given observing time, WFMOS can - observe much more galaxies - observe with much higher S/N WFMOS is thus suitable for - statistical studies - rare objects - clustering and environment - z=6-7 surveys (1um sensitivity) Key point: how to supply good targets to WFMOS comoving length for 1.5deg comoving volume for 1.77deg2

Large-scale structure covered by WFMOS z=1 D=90Mpc z=5 D=200Mpc VIRGO Consortium We should not underestimate cosmic variance. Even one WFMOS FoV is not wide enough.

WFMOS Deep Sky Survey (WFDSS) Area: ～40 deg2 (～4E+8 Mpc3/Δz=1) Targets: galaxies (incl. AGN) at 1<z<7.5 Number of spectra: ～1,000,000 spectra Number of nights: ～100 nights (2hr/targets) Imaging data for target selection: Hyper Suprime-Cam Deep Surveys (1) Deep Survey: 40deg2, r=27.6mag ugrizy + NB (+NIR) (2) Ultra Deep Survey: 3.5deg2, r=28.6mag

Number of Targets in WFDSS Continuum flux-limited samples (color or phot-z): z～1: 10^6 (i<24; M*+1.5) z～3: 3x10^5 (i<25; M=-20.5) z～4: 10^5 (i<25; M=-21.0) z～5: 10^4 (z<25; M=-21.4) z～6: 10^3 (z<25; M=-21.7) Lyman alpha emitters: 10^4 /Δz=0.1 (NB<26) 10 Coma-cluster ancestors per Δz=1 Rare objects: forming clusters (SSA22-like, z=5.7 cluster-like…) forming galaxies (cooling, pop-III) etc

Science Cases For all redshifts For z>6 spatial distribution → environment, dark-halo mass spectra → SFR, age, metallicity, AGN multiband imaging → stellar mass, (SFR, E(B-V), color) - mass- and environment-dependent galaxy evolution (for chemical evolution, see Nagao-san’s talk) - cluster formation, LSS formation - primordial galaxies (cooling, pop-III) (- number density of high-z galaxies) For z>6 - galaxy properties and reionization processes (Ouchi-san’s talk, Goto-san’s talk) redshift SFR, Mstar, age, Z, dust, AGN dark-halo mass environment

Importance of Spectroscopy 3D distribution - environment (pairs, groups, clusters, LSS, …) - cluster and group finding - spatial correlation function Physical quantities - age, SFR, metallicity, AGN, SMBH - accurate derivation of SED, Mstar, E(B-V), … Photometric redshifts (incl. LBG-like techniques) cannot be a substitute.

Existing Spec Surveys are not Large and Deep Enough DEEP2 3.5 deg2 30,000 spectra (0.7<z<1.5; 1.5E+7Mpc3) VVDS 2 deg2? 50,000 spectra at z>1? zCOSMOS-deep 1 deg2 10,000 spectra (1.5<z<3) Yamada Scale (T. Yamada 2008) Survey Area Comoving Volume (Mpc3/Δz=1) Main Targets 1 deg2 E+7 galaxy evolution 10 deg2 E+8 most luminous objects, clusters, LSS 100 deg2 E+9 QSOs, cosmic web 1000 deg2 E+10 dark energy survey

我々は 2 つの意味で幸運な時代にいる (1) ミクロな幸運 21世紀の現在は、銀河進化の謎に迫れる大型の望遠鏡や 装置が使える時代 - TMT, JWST, SPICA, ALMA, SKA, … - FMOS, Hyper Suprime-Cam, WFMOS, … (2) マクロな幸運 宇宙が100億歳余の現在は、銀河進化の全体像を観測し 得る時代 - 銀河進化の重要なできごとがちょうど終わった - もし宇宙初期に生きていたら、質量集積、形態、downsizing、 環境効果などの銀河進化のエッセンスは、すべて未来の できごととなり、観測できなかった - もしずっと未来に生きていたら、銀河進化のエッセンスは 遠過ぎて観測できなかった