COSMIC DOWNSIZINGand

AGN METALLICITYat HIGH REDSHIFT

Roberto MaiolinoINAF - Oss. Arcetri & Oss. Roma

Tohru NagaoINAF - Oss. Arcetri & NAOJ

Alessandro MarconiINAF - Oss. Arcetri

Mass-Metallicity relationin galaxies at z=0

Tremonti et al. 2004

Chemical version of theChemical version of thecosmic downsizing (anti-hierarchical growth)cosmic downsizing (anti-hierarchical growth)

z=01

35

lg M* = 8

10

9

11

12

Evolution of the Mass-Metallicity relation:Evolution of the Mass-Metallicity relation: massive galaxies chemically evolve rapidly at high-zmassive galaxies chemically evolve rapidly at high-z

QSOs QSOs

(Kobulnicky et al. 2003, Shapley et al. 2005, Savaglio et al. 2005, Maiolino et al. 2006)

The metallicity of theThe metallicity of theBroad Line Region at 2<z<4.5Broad Line Region at 2<z<4.5

~ 5000 QSO optical spectra (UV-rest) from SDSS DR2~ 5000 QSO optical spectra (UV-rest) from SDSS DR2

Sample large enough to disentagle theSample large enough to disentagle thedependence on redshift and on luminositydependence on redshift and on luminosity

22 high quality composite spectra22 high quality composite spectrain bins of redshift and luminosityin bins of redshift and luminosity

Nagao, Marconi & Maiolino 2006

NV

SiII

OI+SiIICII

SiIVHeII

OIV]NIV]

CIV

“1600A bump”

OIII]AlII

SiIII]AlIII

Ly

CIII]

NIV+AlII+NIII+Fe

fit residuals

Accurate fluxes for15 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” metallicityfor each [z,L] bin

Nagao et al. 2006

Metallicity ofMetallicity ofthe BLR at 2<z<4.5the BLR at 2<z<4.5

Average trendsAverage trends

- Significant dependenceSignificant dependence on Luminosityon Luminosity

- No evolution with redshiftNo evolution with redshift

Consequence of the mass-metallicity relationZ M* MBH LQSO

...but also dependence on accretion rate(Shemmer et al. 2004)

No metallicity evolution evenNo metallicity evolution evenin the most distant QSOs at 4.5<z<6.4in the most distant QSOs at 4.5<z<6.4

(close to re-ionization)(close to re-ionization)

From near-IR spectraFrom near-IR spectra(=UV rest-frame) of 20 QSO(=UV rest-frame) of 20 QSO

J1148+52z=6.4

QSOs probe the most extreme cases ofanti-hierarchical growth:

their host galaxies are fully evolved, from the chemicalpoint of view, already at very high redshift

z=01

35

lg M* = 8

10

9

11

12QSOs QSOs

Large number of emissionLarge number of emissionlines: possible to contrainlines: possible to contrainabundances patternsabundances patterns

Best matchesBest matcheswith abundanceswith abundancesat/after the windat/after the wind QSOs

best fit

Selection effectsSelection effectsassociated withassociated withQSO-galaxy coevolutionQSO-galaxy coevolution

Star formation +Obscured AGN

Passive evolution +Unobscured QSO

wind

Pipino & Matteucci 2004Granato et al. 2004

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<3.8NLR evolution at 1.2<z<3.8

Nagao, Maiolino & Marconi 2006

- 51 optical spectra (UV-rest) of high redshift- 51 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- 10 optical spectra (UV-rest) of high redshfit X-ray selected QSO2 in the Chandra Deep Field Southselected 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)

(local)C

IV /

HeII

1

0.5

3

CIV

/ H

eII

1

0.5

3

CIII] / CIV0.3 1

NLR evolutionNLR evolutionat 1.2<z<3.8at 1.2<z<3.8

No evolution with redshiftNo evolution with redshiftamong HzRG at 1.2<z<3.8among HzRG at 1.2<z<3.8

Dependence on LuminosityDependence 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 thestrong enrichment of carbon in the host already at z=6.4 host already at z=6.4

J1148+52z=6.4

same [CII]/FIR as loc. ULIRGssame [CII]/FIR as loc. ULIRGssame [CII]/CO as loc. ULIRGssame [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 ofAGN-galaxy joint evolutionary models