1. Tohru Nagao Observational Study on
the Chemical Evolution of the Universe
through WFMOS
Tohru Nagao
(Ehime Univ.)

2. Why Metallicity?
NGC 2403
(©Subaru, 2005)

3. The SDSS Era (a few years ago…)
NGC 2403
(©Subaru, 2005)

4. SDSS 53000 spectra @ 0.0 < z < 0.2
Metallicity of Galaxies at z=0.1
Tremonti et al. (2004)
“Mass-Metallicity Relation”
“Luminosity-Metallicity Relation”
SDSS < z < 0.2

5. 6 decades in stellar mass
Metallicity of Galaxies at z=0.1 (cont.)
Assuming “closed box”:
Z = y ln(μgas-1 )  “yeff”
Tremonti et al. (2004)
Lee et al. (2006)
M-Z relation for
6 decades in stellar mass

6. GDDS & CFRS ~60 spectra @ 0.4 < z < 1.0
Metallicity of Galaxies at z=0.7
Savaglio et al. (2005)
L-Z z=0.1
Savaglio et al. (2005)
Evolving L-Z relation !!
M-dependent M-Z evolution !!
GDDS & CFRS ~ < z < 1.0

7. ~100 spectra of BM/BX (UV-selected galaxies)
Metallicity of Galaxies at z=2
Erb et al. (2007)
~100 spectra of BM/BX (UV-selected galaxies)

8. ~10 spectra of LBGs (UV-selected galaxies)
Metallicity of Galaxies at z=3
Maiolino, Nagao, et al., (2008)
“Down-sizing chemical evolution” !!!?
~10 spectra of LBGs (UV-selected galaxies)
z = 0
z = 1
z = 2
z = 3

9. M-Z Evolution: Observations vs. Models
Simulation:
Kobayashi et al. 2007
Observations:
Maiolino, Nagao, et al.
2008

10. 15 sBzK’s (non-UV-selected)
M-Z Evolution: Observations vs. Observations
Hayashi et al. (2009)
with the SDF team
15 sBzK’s (non-UV-selected)
z~2 (sBzK)
No evolution in M-Z rel.
between z~0 and z~2 !?
M-Z rel. depends on
galaxy stellar pop. !?
z~0 (SDSS)
z~2 (BMBX)

11. M-Z Evolution: Observations vs. Observations
z~0 (SDSS)
z~1 (Savaglio+)
z~2 (Erb+)
z~3 (Maiolino,TN+)
z~1 (VVDS)
“Anti-Downsizing” !?
Completeness affects
strongly on the M-Z !?
~1000 VVDS targets
Lamareille et al. (2009)

12. “R23” M-Z Evolution through WFMOS !!
Uniform derivation of the metallicity at 0<z<1
 MANDATORY: 3700A < lobs < 10000A
Based on a large sample down to IAB~23
 Well matched to the HSC-Wide survey
Stellar mass  spectroscopic features (like SDSS)
Nagao et al. (2006c)
“R23”

13. クェーサーも やっとるけん！ The SDSS Era (a few years ago…) NGC 2403
Translation to English:
Hey You!! Why not recalling QSOs!?
クェーサーも
やっとるけん！
NGC 2403
(©Subaru, 2005)

14. Rest-frame UV spectrum of QSOs
SDSS QSO composite
VandenBerk et al. (2001)
Very Luminous, Abundant UV Emission Lines

15. SDSS QSO Stacking Analysis
-24.5>MB> (643 QSOs)
-25.5>MB> (1497 QSOs)
-26.5>MB> (917 QSOs)
-27.5>MB> (105 QSOs)
-28.5>MB> (5 QSOs)
Nagao et al. (2006b)
Redshift
Luminosity

16. LAGN ZAGN Zgal MBH Mgal Galaxies vs. QSOs
Strong M-Z evolution (?) in galaxies
No L-Z evolution in AGNs
Erb+06
galaxies at z~2
SDSS galaxies
at z~0
Log (Mstar/Msun)
12 + Log(O/H)
LAGN
ZAGN
Zgal
MBH
Mgal

17. QSO Metallicity through WFMOS !!
Down to +2mag fainter than SDSS QSOs
Targets  2000 deg2 HSC-wide survey (SWANS)
Metallicity up to z~5  3700A < lobs < 10000A
The SWANS Collaboration

18. Summary Metallicity Evolution of Star-Forming Galaxies
~ Crucial Observable: the Mass-Metallicity Relation
~ Chemical Downsizing? Anti-Downsizing??
~ Requiring Large Sample without Strong Selection Bias
~ WFMOS Systematic Study at z<1  3700A<l<10000A
(2) Metallicity Evolution of Active Galactic Nuclei
~ Powerful Strategy: the Stacking Analysis
~ No Evolution in L-Z Relation? Even down to Low-L??
~ WFMOS Study at 2<z<5  3700A < l < 10000A
~ Target Selection: Synergy with the HSC-Wide Survey