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Yanchun Liang (NAOC, China) 2005-08, Lijiang

The Luminosity-Metallicity and Mass-Metallicity Relations of 0.4<z<1 Luminous Infrared Galaxies :. ---implication on the mass and metal assembly of galaxies. Yanchun Liang (NAOC, China) 2005-08, Lijiang. Collaboration with Francois Hammer, Hector Flores, Francois Assemat

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Yanchun Liang (NAOC, China) 2005-08, Lijiang

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  1. The Luminosity-Metallicityand Mass-Metallicity Relations of 0.4<z<1 Luminous Infrared Galaxies : ---implication on the mass and metal assembly of galaxies Yanchun Liang (NAOC, China) 2005-08, Lijiang

  2. Collaboration with Francois Hammer, Hector Flores, Francois Assemat at Paris-Meudon Observatory; David Elbaz, Delphine Marcillacat Saclay-Service d’Astrophysique; Nicolas Gruel at Florid University; Xianzhong Zhengat MPIE; Licai Deng at NAOC; Catherine J. Cesarsky at ESO.

  3. 240 mm How much star formation was hidden by dust over the history of the universe ? (1) IRAS(z<0.3): detected tens of thousands of galaxies with the FIR radiation luminosities From 106Lsun to ~1013Lsun, but only ~2% of the local bolometric luminosity density is due to the luminous IR galaxies (Soifer et al. 1987, ARA&A, 25, 187; Sanders & Mirabel 1996, ARA&A, 34, 749) (2) COBE(DIRBE) detected a diffuse background at l > 140 mm (3) Surveys at 15,90,170,450,850mm (ISO, SCUBA) • strong evolution (Elbaz et al. 2002, A&A 384, 848)

  4. ISOCAM 15 mm MIR source counts • ISO 15 mm source counts show strong evolution • The comoving density of infrared light due to the luminous galaxies (LIR>1011Lsun) was more than 40 times larger at z~1 than today • The main responsibility: • the luminous Infrared starburst galaxies seen by ISO at z>0.4, • SFRs > 50 Msunyr-1 (Elbaz et al. 1999, A&A Lett., 351, L37) (Elbaz et al. 2002, A&A 384, 848; Elbaz & Cesarsky, 2003, Science, 300, 270; Flores et al. 1999, ApJ 517, 148) (4) Most of ISOCAM (>75%)galaxies are Starbursts, AGN only contribute ~20% (Elbaz et al. 2002 A&A 384 848; Fadda et al. 2002, A&A, 383, 838; Flores et al. 1999; Franceschini et al. 2003, A&A, 403, 501; Liang et al. 2003b, A&A, submitted)

  5. The Spitzer view on the history of dusty star formation at 0<z<1 Evolution of the comoving IR energy density up to z=1 (green-filled region) and the respective contributions from low luminosity galaxies (i.e., LIR<1011Lsun, blue-filled area), ``infrared luminous'' sources (i.e., LIR>1011Lsun, orange-filled region) and ULIRGs (i.e., LIR>1012Lsun, red-filled region). The solid line evolves as (1+z)3.9 and represents the best fit of the total IR luminosity density at 0<z<1. Estimates are translated into an ``IR-equivalent SFR'‘ density given on the right vertical axis, where an absolute additional uncertainty of $\sim$\,0.3\,dex should be added to reflect the dispersion in the conversion between luminosities and SFR. (Le Flo’ch et al. 2005, ApJ, astro-ph/0506462 )

  6. Spectroscopy (VLT/FORS2)follow-upfor a large sample of ISOCAM-selected sources(Extinction, Metallicities,L-Z, Mass-Z) (Liang et al. 2004, A&A, 423, 867)

  7. 1. The ISO-selected sample : 105 in 3 fields Sample • CFRS 3h, • UDSR (Ultra-Deep-Survey-Rosat, Marano field), • UDSF (Ultra-Deep-Survey-Firback, Marano field) (Flores et al. 2004, Elbaz et al. 2004, in preparation ) 2. The Optical Observations using VLT/FORS2 with R600 and I600 spectrograph with a resolution of 5 Å, R=1200 5000 - 9000 Å, slit width 1.2"slit length 10" 3. Redshift identifation 92 zmedian=0.587 (64 with z>0.4) 4. Infrared luminosities Log(LIR/Lsun)med=11.26 ( LIRGs with Log(LIR/Lsun)>11) 5. Emission Line Galaxies (ELG) 85% EL galaxies in the ISO-detected objects , 81% EL galaxies in the total

  8. IR luminosity Log(LIR/Lsun)med =11.26 Similar to Veilleux et al.1995, Kim et al. 1995: 11.34 for BGSs 11.38 for WGSs H0=70 km/s/Mpc 11 12 13 9 10 M=0.3, L=0.7

  9. Examples in UDSF Deblending…

  10. z=0.7094 Log(LIR/Lsun)=11.38

  11. Estimate dust extinction Stellar absorption correction Jacoby et al. (1984) • Using Hb/Hg ratio :A V(Balmer) • Using energy balance between Hbetra and IR:A V(IR)

  12. Diagnostic diagram: Starbursts Most of them (>77%) are HII-region-like galaxies Consistent with other fields:>70% of ISOCAM/15m galaxies, “starbursts”

  13. Oxygen abundances in ISM R23 and calibration from Kobulnicky et al. 1999 12+log(O/H) = 8.35 – 8.93, median 8.67  Luminosity-Metallicity relation (L-Z) & Mass-Metallicity relation (Mass-Z)

  14. L-Z relation: z> 0.4 LIRGs are metal deficient ! z> 0.4 LIRGs are 0.3 dex metal-poor from local disks (at a constant MB): ~ 50% (12+log(O/H) = 8.35 – 8.93, median 8.67) ! They can reach local disks locus assuming an infall time of ~ 1 Gyr (PEGASE2, Fioc and Rocca-Volmerange, 1999,astro-ph/9912179: Mtot=1011Msun, also see Kobulnicky et al. 2003, ApJ, 599, 1006) 03.0035 (Liang et al. 2004, A&A, 423, 867)

  15. Are massive spirals already formed at z~ 1 ? ! Connection between LIRGs and disks (z>0.4) (HST morphologies and color maps) : 40% of LIRGs are large disks (Zheng et al, 2004, A&A) !Lilly et al (1998)large disk sample (rdisk > 4 h50-1 kpc) at 0.5 < z < 1:32 (+/-13)% of them are LIRGs ! LIRGs have large stellar masses: 1.4 1010MO <MK < 2.9 1011MO (see also Franceschini et al. 2003, A&A, 403, 501) ! LIRGs have high SFRs: >50 Msunyr-1 , TSF(M/SFR)=0.1-1 Gyr

  16. SFR-Mass relation (Mass double time scale: 0.1-1 Gyr) Time (Gyr)

  17. The Mass-Metallicity relation of 0.4<z<1 galaxies

  18. 30% to 50% of the mass locked in stars in present day galaxies actually condensed into stars at z<1 (Dickinson et al. 2003; Pozzetti et al. 2003; Drory et al. 2004; Bell 2004) Which kinds of galaxies are mainly responsible for such star formation fraction?

  19. The near-IR K-band luminosity is more directly related to the stellar mass of galaxies since it is less affected by star formation and by dust (Charlot 1998; Bell & de Jong 2000): We compare the MK-metallicity (mass-Z) relations of these intermediate-z galaxies with those of local star-forming galaxies. (Liang, Hammer, Flores 2005, A&A, submitted)

  20. The 3 local sample galaxies to compare: NFGS (Nearby Field Galaxy Survey) by Jansen et al. 2000a,b KISS ( Salzer et al. 2005) SDSS (Tremondi et al. 2004; Bell et al. 2003)

  21. NFGS from Jansen et al. 2000a,b Such z> 0.4 galaxies are 0.3 dexmore metal-poor from local disks (at a given MK): ~ 50%

  22. KISS from Salzer et al. 2005

  23. SDSS Tremonti et al. 2004, Bell et al. 2003; The 7 galaxies at z~2.3 from Shapley et al. 2004

  24. Summary • Spectroscopy follow-up for a ISO-selected sample galaxies with 0.4<z<1 • We study their metallicities on the basic of VLT/ FORS2 spectra, the median oxygen abundance of them is 12+log(O/H)~8.67: ~0.3dex more metal deficient than the local star forming galaxies at the given magnitude or stellar mass • By comparing with the local galaxies (e.g. NFGS, KISS, SDSS) and the high-z (z~2.3) galaxies, we can get a basic understanding on the assembly of the metals of galaxies: ~ 50% of metals of these intermediate-z galaxies was formed since z ~ 1

  25. Thank you!

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