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Galaxy Evolution and WFMOS History of Galaxies Present-day Universe: SDSS

Explore the history of galaxies & universe evolution with a focus on properties, formation, & environmental factors. Learn about galaxy clusters, reionization, & cutting-edge research using WFMOS for statistical studies.

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Galaxy Evolution and WFMOS History of Galaxies Present-day Universe: SDSS

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

  2. 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 8 Age of Uniserve (x10 yr)

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

  4. 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)

  5. 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

  6. 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

  7. 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.

  8. What can WFMOS do? WFMOS performance - 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

  9. 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.

  10. 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-CamDeep Surveys (1) Deep Survey: 40deg2, r=27.6mag ugrizy + NB (+NIR) (2) Ultra Deep Survey: 3.5deg2, r=28.6mag ugrizy + NB (+NIR)

  11. 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

  12. Science Cases For all redshifts 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 environment dark-halo mass

  13. 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.

  14. 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)

  15. 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

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