COSMIC DOWNSIZING and AGN METALLICITY at HIGH REDSHIFT Roberto Maiolino INAF - Oss. Arcetri & Oss. Roma Tohru Nagao INAF - Oss. Arcetri & NAOJ Alessandro Marconi INAF - Oss. Arcetri

Mass-Metallicity relation in galaxies at z=0 Tremonti et al. 2004

Chemical version of the cosmic downsizing (anti-hierarchical growth) z= lg M * = Evolution of the Mass-Metallicity relation: massive galaxies chemically evolve rapidly at high-z massive galaxies chemically evolve rapidly at high-z QSOs (Kobulnicky et al. 2003, Shapley et al. 2005, Savaglio et al. 2005, Maiolino et al. 2006)

The metallicity of the Broad Line Region at 2<z<4.5 ~ 5000 QSO optical spectra (UV-rest) from SDSS DR2 Sample large enough to disentagle the dependence on redshift and on luminosity 22 high quality composite spectra in bins of redshift and luminosity Nagao, Marconi & Maiolino 2006 NV SiII OI+SiII CII SiIV HeII OIV] NIV] CIV “1600A bump” OIII] AlII SiIII] AlIII Ly  CIII] NIV+AlII+NIII+Fe fit residuals

Accurate fluxes for 15 emission lines Photoionization models: - Cloudy - Integration over different distributions (in r and n) of gas clouds - Spanning various gas metallicities (abundances prop. to solar, except for N) matching flux ratios (+ constraints from EW) Hagai (!) “best” metallicity for each [z,L] bin Nagao et al. 2006

Metallicity of the BLR at 2<z<4.5 Average trends - Significant dependence on Luminosity on Luminosity - No evolution with redshift Consequence of the mass-metallicity relation Z  M *  M BH  L QSO...but also dependence on accretion rate (Shemmer et al. 2004)

No metallicity evolution even in the most distant QSOs at 4.5<z<6.4 (close to re-ionization) From near-IR spectra (=UV rest-frame) of 20 QSO J z=6.4

No evolution even in critical elements such as Fe (whose enrichment is delayed) though UV Fe bump difficult to interpret... Verner et al. 2004, Baldwin et al. 2004

QSOs probe the most extreme cases of anti-hierarchical growth: their host galaxies are fully evolved, from the chemicalpoint of view, already at very high redshift z= lg M * = QSOs

Large number of emission lines: possible to contrain abundances patterns Best matches with abundances at/after the wind QSOs best fit Selection effects associated with QSO-galaxy coevolution  Star formation + Obscured AGN Passive evolution + Unobscured QSO wind Pipino & Matteucci 2004 Granato et al        

The Broad Lines sample only a tiny, nuclear region... not representative of the host galaxy? Use Narrow Lines in obscured AGNs

NLR evolution at 1.2<z<3.8 Nagao, Maiolino & Marconi optical spectra (UV-rest) of high redshift narrow line radio galaxies (HzRG) narrow line radio galaxies (HzRG) - 10 optical spectra (UV-rest) of high redshfit X-ray selected QSO2 in the Chandra Deep Field South selected QSO2 in the Chandra Deep Field South CIV/HeII vs. CIII]/CIV diagram: CIV/HeII vs. CIII]/CIV diagram: - sensitive to metallicity - sensitive to metallicity - removes degeneracy from U - removes degeneracy from U - possible to control effects of shocks and dust - possible to control effects of shocks and dust

(local) CIV / HeII CIV / HeII CIII] / CIV 0.31 NLR evolution at 1.2<z<3.8 No evolution with redshift among HzRG at 1.2<z<3.8 Dependence on Luminosity

At z>4 little information on NLR metallicity...but information on gas in host galaxy for some QSOs  strong enrichment of carbon in the host already at z=6.4 host already at z=6.4 J z=6.4 same [CII]/FIR as loc. ULIRGs same [CII]/CO as loc. ULIRGs

CONCLUSIONS Luminosity-Metallicity relation: consequence of Mass-Metallicity relation in galaxies No metallicity evolution with redshift: QSO are extreme cases of the cosmic downsizing (in its chemical version) BLR & NLR Abundance patterns matching expectations of AGN-galaxy joint evolutionary models