Stellar-mass Metallicity Relation at High Redshifts Stellar-mass Metallicity Relation at z~1. 4 Kouji OHTA ( Kyoto University ) K. Yabe, F. Iwamuro, S. Yuma, M. Akiyama, N. Tamura, FMOS team et al. 2011 年 11 年 2 年 年 年年年 Near Field Cosmology!? Extra-galactic Archaeology! 1
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Stellar-mass Metallicity Relation at High Redshifts Stellar-mass Metallicity Relation at z~1. 4 Kouji OHTA ( Kyoto University ) K. Yabe, F. Iwamuro, S.
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Stellar-mass Metallicity Relation at High Redshifts
Stellar-mass Metallicity Relation at z~1. 4
Kouji OHTA ( Kyoto University )K. Yabe, F. Iwamuro, S. Yuma, M. Akiyama, N. Tamura, FMOS team et al. 2011 年 11 月 2 日
於 修善寺
Near Field Cosmology!?Extra-galactic Archaeology!
1
Tracing chemical evolution
Galactic disk stars Twarog (1980)
Galaxy surveys
Chemical evolutionÞEvolution of galaxies and MW Galaxy
But the metallicity here isfor rather bright/massive galaxies…
Lilly et al. 2003, ApJ 597, 730 (CFRS)
2
Mass-metallicity relation~53,000 SF galaxies at z~0.1(SDSS) Tremonti et al. ApJ 613, 898 (2004)
Need to establish relations atvarious redshifts =>Chemical evolution of galaxies/MW
Even at a fixed stellar mass,There is a significant scatter around the relation=> Physical origin is unknown yet
Related to nature of GRB hosts,Origin of long GRBs 3
Evolution of mass-metallicity relation
Mannucci et al. 2009, MN 398, 1915
z~0.7: 56 SF galaxies Savaglio et al. 2005, ApJ 635, 260
z~2.2: 90 SF galaxies with Stacking analysis Erb et al. 2006, ApJ 644, 813
z~3: ~20 SF galaxies Maiolino et al. 2008, AA 488, 463
4
Why M-Z relation at z~1.4?
Hopkins & Beacom , 2006, ApJ 651, 204
What is the M-Z relation close to/just after the peak epoch of cosmic SF history? => a major step in chemical evolution?
How’s the scatter? => larger scatter in higher redshifts?
What is the origin of the scatter? => key parameter to understand the evoliution of M-Z relation (&chemical evolution of galaxies)
Cosmic SF history
We need a large sample of SF galaxies at z=1-2!
5
Fibre Multi-Object Spectrograph (FMOS) on Subaru Telescope
• 0.9-1.8um R~700, (R~3000 in HR mode)
• 400 fibres in 30’ FoV
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Sample
• K(AB) < 23.9 mag in SXDS/UDS• Stellar mass > 10^9.5 Msun• 1.2 < z_ph < 1.6 FMOS can cover Hβ -- Hα 、 [NII]6584• Expected Hα flux > 1.0x10^-16 erg/s/cm^2 calculated from SFR(UV) & E(B-V)nebular from UV slope• Randomly selected ~300 targets
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Example of spectraTypical exp time ~ 3 h Hα detection: 71 galaxies
Mass-metallicity relation at z~1.4SN < 1.5 for [NII]6584
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• MZ relation locates between z~0.1 (Tremonti+) and z~2 (Erb+) (after correcting for the metallicity calibration & stellar mass (IMF))
• Agree with recent simulation Galaxy mass dependent outflow model (vzw)
Dave et al. MN 416, 1354 (2011)
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Scatter of the MZ relation• Try to constrain the scatter• Deviation from the MZ relation (after removing the obs error)• Smaller in massive side• Comparable to z~0.1• But strictly speaking they are lower limits=> Larger scatter at z~1.4
● z~0.1
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What makes the scatter?2nd parameter problem at high-z