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Black hole accretion and host galaxies of obscured quasars

Black hole accretion and host galaxies of obscured quasars. Vincenzo Mainieri. with. Angela Bongiorno, Andrea Merloni & COSMOS. Introduction. AGN-galaxies co-evolution.

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Black hole accretion and host galaxies of obscured quasars

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  1. Black hole accretion and host galaxies of obscured quasars Vincenzo Mainieri with Angela Bongiorno, Andrea Merloni & COSMOS

  2. Introduction AGN-galaxies co-evolution M-  relation: AGN and galaxies co-evolve (Magorrian et al. 1998; Gebhardt et al. 2000; Ferrarese & Merrit 2000; Tremaine et al. 2002) Hopkins+08 Hickox+09 Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

  3. 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

  4. 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

  5. X-ray properties Stacking Stacked X-ray spectrum • 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 NH=(5.68.33.3)1022 cm-2 EW(FeK)~104 eV See Poster G41 (Salvato+11) Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

  6. QSO-2 sample Redshifts Optical spectroscopy Dn(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

  7. SED SED fitting : galaxy + AGN 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 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 14 Bands Used 6 SUBARU bands (U-z) I + K band (CFHT) 4 Spitzer/IRAC 24μm Spitzer/MIPS Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

  8. 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 A strong MIR (12.3 m) / X-ray (2-10 keV) correlation : log L12.3m=(-4.37±3.08)+(1.106±0.071) log L2-10 keV Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

  9. 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

  10. Host galaxy properties Stellar Mass Stellar Mass • 80% of the hosts have M*>1010 Msun • the fraction increases with M* • Chabrier IMF • Ilbert+10: parent sample of ~70,000 galaxies selected in theredshift 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 Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

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

  12. Host galaxy properties Star formation SFR-M* correlation • @ 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> 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). Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

  13. Host galaxy properties Star formation SFR-M* correlation • @ 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> Lutz,VM+10 Daddi+10 Mullaney+11 Daddi+10 Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

  14. 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

  15. Host galaxy properties Morphology Morphology 35 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-dominated Disks Mergers 23% F160W (H) 57% 20% F775W (i) Credits to the CANDELS team Lack of evidence is not necessarily evidence of lack: e.g. quasar phase at the end of the merging process (Di Matteo +05; Conselice03)? Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

  16. 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 <MBH>~4x108 Msun • lowest mass BHs are the fastest accretors (e.g McLure & Dunlop 2002; Netzer & Trakhtenbrot 2007) <MBH>~1x108 Msun Vincenzo Mainieri (ESO) QSO-2 and their host galaxies The X-ray Universe 2011

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

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