Black hole accretion and host galaxies of obscured quasars

Vincenzo Mainieri

with

Angela Bongiorno, Andrea Merloni & COSMOS

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

Introduction

AGN-galaxies co-evolutionM- relation: AGN and galaxies co-evolve (Magorrian et al. 1998; Gebhardt et al. 2000; Ferrarese & Merrit 2000; Tremaine et al. 2002)

Hickox+09Hopkins+08

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

Introduction

AGN-galaxies co-evolution

Where the “food” is coming from?

Secular processes Major mergers

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

QSO-2 sample Sample selection

Sample selection

Selection criteria:

LX>1044 erg s-1

NH>1022 cm-2

142 QSO-2

The galaxy to AGN contrast ratio is maximized: “easier” to study the morphology of the host as well as its stellar mass and SFR.Caveat: UV light can be contaminated from scattered AGN light, SFR diagnostics (e.g. H, [OII]) excited by accretion power rather than young stars, etc..

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

X-ray properties Stacking

Stacked X-ray spectrum

NH=(5.68.33.3)1022 cm-2

EW(FeK)~104 eV

• For the 34 QSO-2 with spectroscopic redshifts, only the rest-frame 2-10 keV band was used for each spectrum.

• Spectral binning was designed to match a fixed rest-frame 200eV intervals.

• The total accumulated counts are 4763

See Poster G41 (Salvato+11)

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

QSO-2 sample Redshifts

Optical spectroscopyDn(4000) = 1.19±0.02 (Balogh+99)HδA = 4.7±0.4 (Worthey&Ottaviani97)

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

SED

SED fitting : galaxy + AGN14 Bands Used

6 SUBARU bands (U-z)I + K band (CFHT)

4 Spitzer/IRAC24μm Spitzer/MIPS

Galaxy templates: - 14 phenomenological: Polletta (2007) - Libr. of synthetic sp. (B&C) a) 10 declining SFH SFR µe-t/t t=[0.1-30] Gyr tage=[50Myr-5 Gyr] tage<tuniv(z) 0 < E(B-V) <0.5 b) 1 constant SF

AGN template: -Richards et al. (2006): mean QSO SED from 259 IR-selected QSOs from the SDSS with Spitzer photometry

1<E(B-V)<9: <NH>~5x1022cm-2 (assuming 1/3 of Galactic dust-to-gas) -> E(B-V)~3

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

SED

SED fitting : MIR/X-ray correlation

Gandhi+09

VISIR/VLT high resolution imaging of a sample of local Seyferts: the least contaminated core fluxes

• ~70 pc at z=0.01

• <40% contaminating star-formation in the unresolved flux

log L12.3m=(-4.37±3.08)+(1.106±0.071) log L2-10 keV

A strong MIR (12.3 m) / X-ray (2-10 keV) correlation :

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

SED

SED fitting : galaxy + AGN

Chabrier IMF

2 minimization comparing observed and template fluxes at the redshift of the QSO-2

PRIORS

• The maximum allowed age is the age of the Universe at the redshift of the source

• The AGN SED should fit the 12.3 m flux predicted using the Gandhi+09 correlation

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

Host galaxy properties Stellar Mass

Stellar Mass

• Chabrier IMF

• Ilbert+10: parent sample of ~70,000 galaxies selected in the redshift range 0.8-1.5, where there is a good completeness for M*> 5x109 Msun

• We folded the parent sample with the X-ray sensitivity map

• 80% of the hosts have M*>1010 Msun

• the fraction increases with M*

• 80% of the hosts have M*>1010 Msun

• the fraction increases with M*

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

Host galaxy properties Rest frame colors

Host galaxies classification

Photometric classification

Separating red and blue galaxies (Wilmer+06):

“Blue” QSO-2 : 42%

“Red” QSO-2 : 58%

Star formation activity classification

Active: log(sSFR/Gyr-1) > -1 (62%)

Quiescent: log(sSFR/Gyr-1) < -1 (38%)

~20% “red” hosts are dusty star-forming galaxies

(see also Cardamone+10, Lusso+11)

~20% “red” hosts are dusty star-forming galaxies

(see also Cardamone+10, Lusso+11)

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

Host galaxy properties Star formation

SFR-M* correlation

Goal: compare the star formation in the QSO2 hosts with the tight correlation between SFR and M* of blue star-forming galaxies (e.g. Noeske+07; Daddi+07; Elbaz+07; Pannella+09; Rodighiero+10).

• @ z~1 : 62% of the hosts are star-forming and their rates are comparable to the main-sequence “Noeske” relation

• @ z~1 : 62% of the hosts are star-forming and their rates are comparable to the main-sequence “Noeske” relation

• Similar evolution of the <SSFR>• Similar evolution of the <SSFR>

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

Host galaxy properties Star formation

SFR-M* correlation

Lutz,VM+10

Mullaney+11

Daddi+10

Daddi+10

• @ z~1 : 62% of the hosts are star-forming and their rates are comparable to the main-sequence “Noeske” relation

• @ z~1 : 62% of the hosts are star-forming and their rates are comparable to the main-sequence “Noeske” relation

• Similar evolution of the <SSFR>• Similar evolution of the <SSFR>

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

Host galaxy properties Morphology

Merging?

• Greene et al. 2009 (SDSS QSO-2): nearly one-quarter have highly disturbed morphologies

• Liu et al. 2009 (SDSS QSO-2): high fraction of double cores and physically associated companions from long-slit spectroscopy.

Cisternas+11: a) no difference in the distortion fractions between inactive and active galaxies; b) ~65% of the AGN hosts are disk dominated.

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

Host galaxy properties Morphology

Morphology35 QSO-2 with z<1.2 & IAB<24

ZEST+ (Scarlata+07; Carollo+11): Five non-parametric diagnostics (asymmetry A, concentration C, Gini coefficient G, 2nd order moment of the brightest 20% of galaxy pixels M20, ellipticity e) + Sersic index n

Bulge-dominatedDisks Mergers

Lack of evidence is not necessarily evidence of lack: e.g. quasar phase at the end of the merging process (Di Matteo +05; Conselice03)?

23%

20%

57%

F7

75W

(i)

F1

60W

(H

)

Credits to the CANDELS team

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

QSO-2 sample

Morphology and accretion rate

• bulge dominated galaxies tend to host low Edd ratios BHs • disks and mergers host high Edd ratios BHs

• bulge dominated galaxies tend to host low Edd ratios BHs • disks and mergers host high Edd ratios BHs

• lowest mass BHs are the fastest accretors (e.g McLure & Dunlop 2002; Netzer & Trakhtenbrot 2007)

• lowest mass BHs are the fastest accretors (e.g McLure & Dunlop 2002; Netzer & Trakhtenbrot 2007)

<MBH>~1x108 Msun

<MBH>~4x108 Msun

Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

Conclusions

• Type-2 QSOs reside almost exclusively in massive galaxies, 80% have M*>1010 MSUN and the fraction of galaxies hosting them monotonically increases with M*

• The majority of the hosts (>60%) are actively forming stars

• The SSFR of QSO-2 hosts is similar to what observed for star-forming (“Noeske”) galaxies at z~1.

• The evolution of SSFR of QSO-2 hosts is similar to the one of SFGs.

• Morphological analysis suggests that the majority of the hosts are bulge dominated.

• We do not find clear signature of merger activity for the majority of the hosts but it could be a time issue: QSO phase at the end of a major merger event.Difficult to test the quasar fueling models by studying the morphology.