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

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The Luminosity-Metallicity and Mass-Metallicity Relations of 0.4

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

  • The Luminosity-Metallicityand Mass-Metallicity Relations of 0.4

  • Collaboration with Francois Hammer, Hector Flores, Francois Assemat at Paris-Meudon Observatory;David Elbaz, Delphine Marcillac at Saclay-Service dAstrophysique;Nicolas Gruel at Florid University;Xianzhong Zheng at MPIE;Licai Deng at NAOC;Catherine J. Cesarsky at ESO.

  • How much star formation was hidden by dust over the history of the universe ?(2) COBE (DIRBE) detected a diffuse background at l > 140 mm

    (3) Surveys at 15,90,170,450,850mm (ISO, SCUBA) strong evolution(1) IRAS (z

  • ISOCAM 15 mm MIR source countsISO 15 mm source counts show strong evolutionThe 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)

  • (Le Floch et al. 2005, ApJ, astro-ph/0506462 )Evolution of the comoving IR energy density up to z=1 (green-filled region) and the respective contributions from low luminosity galaxies (i.e., LIR1011Lsun, 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

  • Spectroscopy (VLT/FORS2)follow-up

    for a large sample of ISOCAM-selected sources

    (Extinction, Metallicities,L-Z, Mass-Z)(Liang et al. 2004, A&A, 423, 867)

  • 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 )1. The ISO-selected sample : 105 in 3 fields 2. The Optical Observations using VLT/FORS2 with R600 and I600spectrograph with a resolution of 5 , R=12005000 - 9000 , slit width 1.2" slit length 10"Log(LIR/Lsun)med=11.26 ( LIRGs with Log(LIR/Lsun)>11) 3. Redshift identifation4. Infrared luminosities 92 zmedian=0.587 (64 with z>0.4)5. Emission Line Galaxies (ELG) 85% EL galaxies in the ISO-detected objects , 81% EL galaxies in the total

  • IR luminositySimilar to Veilleux et al.1995,Kim et al. 1995:11.34 for BGSs11.38 for WGSsH0=70 km/s/MpcM=0.3, L=0.7Log(LIR/Lsun)med=11.26910111213

  • DeblendingExamples in UDSF

  • z=0.7094Log(LIR/Lsun)=11.38

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

  • Diagnostic diagram: StarburstsMost of them (>77%) are HII-region-like galaxiesConsistent with other fields:>70% of ISOCAM/15m galaxies, starbursts

  • Oxygen abundances in ISM12+log(O/H) = 8.35 8.93, median 8.67R23 and calibration from Kobulnicky et al. 1999Luminosity-Metallicity relation (L-Z)& Mass-Metallicity relation (Mass-Z)

  • L-Z relation: z> 0.4 LIRGs are metal deficient

    03.0035! 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)(Liang et al. 2004, A&A, 423, 867)

  • Are massive spirals already formed at z~ 1 ?! Lilly et al (1998) large disk sample (rdisk > 4 h50-1 kpc) at 0.5 < z < 1: 32 (+/-13)% of them are LIRGs! 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) ! LIRGs have large stellar masses: 1.4 1010MO 50 Msunyr-1 , TSF(M/SFR)=0.1-1 Gyr

  • Time (Gyr)(Mass double time scale: 0.1-1 Gyr)

    (Hammer et al. 2005,A&A,430,115)

  • The Mass-Metallicity relation of 0.4
  • 30% to 50% of the mass locked in stars in present day galaxies actually condensed into stars at z
  • 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)

  • The 3 local sample galaxies to compare:

    NFGS (Nearby Field Galaxy Survey) by Jansen et al. 2000a,bKISS ( Salzer et al. 2005)SDSS (Tremondi et al. 2004; Bell et al. 2003)

  • NFGS

    from Jansen et al. 2000a,bSuch z> 0.4 galaxies are 0.3 dex more metal-poor from local disks (at a given MK): ~ 50%

  • KISS

    from Salzer et al. 2005

  • SDSS

    Tremonti et al. 2004, Bell et al. 2003;

    The 7 galaxiesat z~2.3 from Shapley et al. 2004

  • Summary

    Spectroscopy follow-up for a ISO-selected sample galaxies with 0.4