black hole accretion and host galaxies of obscured quasars vincenzo mainieri with angela bongiorno,...
TRANSCRIPT
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.