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Obscured AGN in the (z)COSMOS survey. Angela Bongiorno Max-Planck-Institut für extraterrestrische Physik, Garching, GERMANY AND Andrea Merloni Marco Mignoli Gianni Zamorani Marcella Brusa And The COSMOS/zCOSMOS teams. AGN9 , Ferrara, May 25 2010. Starburst & buried Quasar.
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Obscured AGN in the (z)COSMOS survey Angela Bongiorno Max-Planck-Institut für extraterrestrische Physik, Garching, GERMANY AND Andrea Merloni Marco Mignoli Gianni Zamorani Marcella Brusa And The COSMOS/zCOSMOS teams AGN9, Ferrara, May 25 2010
Starburst & buried Quasar Galaxy mergers Gas inflow Hierarchical growth Growth of SMBH AGN feedback Normal galaxies Active Quasar • Complete census of AGN (in particular obscured population) (adapted from Hopkins et al., 2008) • How obscured AGN evolve • Fraction of obscured AGN (as a function of e.g. L and z)
THE COSMIC EVOLUTION SURVEY • 2 deg2 equatorial • HST treasury project • Deep: ACS iAB < 27 • Multi-wavelength observations • Similar volume as SDSS, but fainter and higher z • 19-band photo-z RA = 10:00:28.6 Dec = +02:12:21
Multi-wavelength Data: XMM • VLA 1.4 GHz – 7 μJy • Spitzer-IRAC 3-8 μm – 10 μJy • Spitzer-MIPS 24 µm – 15 mJy • HST-ACS – iAB~27 • Subaru Bvriz – mAB~27 • GALEX N/F UV – mAB~26 • XMM 0.5-10 keV – 10-15 cgs • Chandra 0.5-2 keV -- 2x10-16cgs HST Chandra Spitzer VLA Subaru
SPECTRA: the z-COSMOS project VIMOS @VLT P.I. S. Lilly zCOSMOS Institutes ETH Zurich LAM Marseille LAOMP Toulouse INAF Milano INAF Bologna MPE Garching VIMOS @VLT • 600 hrs of observation with VIMOS on VLT started April 2005 • Spectra will be obtained for: • ~20,000 galaxies at 0.3 < z < 1.0 selected to have IAB<22.5 (BRIGHT SAMPLE) • ~10,000 galaxies at 1.4 < z <2.5 with BAB<25 and chosen by color-selection criteria (DEEP SAMPLE) • Extra targets from XMM, GALEX and radio catalogue
[OIII] Line Luminosity Function I Comparison with other surveys SDSS type2 (Reyes+08) local LF SDSS (Hao+05) XLF XMM-HBS (DellaCeca+08) COSMOS X-ray LF Luminosity-dependent density evolution (LDDE) 1=2.13 2=0.5 L*=1.1 1041 *=2.55 10-5 (Bongiorno, Mignoli, Zamorani et al., 2010 A&A 510, 56B)
Fraction of type-2 AGN SDSS (Reyes08) zCOSMOS • at L[OIII] > Lc, decreasing fraction of type–2 AGN with luminosity • 0.15< z <0.3 from ∼65% to ∼50% from L[O III]=106.2 -108.2 Lto 108.2-109.2L • 0.3< z <0.45 and 0.5< z <0.92 from ∼80% to ∼25% from L[O III =106.2-108.5L⊙ to L[O III]=109.0-109.6L ⊙ • What happen at L[OIII] < Lc? (Bongiorno, Mignoli, Zamorani et al., 2010 A&A 510, 56B)
BH accretion as a function of galaxy properties… SDSS type-2 AGN sample @z<0.3 (Kauffmann & Heckman 2008) Eddington Log(L[OIII]/MBH) =1.7 ~2% Edd Feast:Galaxies rich in cold gas ; BH growth is regulated by small-scale feedback. Famine: Galaxies poor in cold gas. BH accretes ~0.3% - 1% of the mass lost by evolved bulge stars.
BH accretion and star formation… at higher redshift using the 20k zCOSMOS type-2 AGN sample 392 sources @ z~1 (close to the peak of the cosmic AGN and star formation density) • AGN hosts masses through SED fitting Separate the Spectral Energy Distribution of AGN intonuclear+host components and derive the host properties • AGN templates: - Elvis et al. (1994) - E(b-v)=0 - 0.3 in 0.01 steps • Galaxy templates: - 14 phenomenological from Polletta (2007) - Libr. of synthetic sp. (Bruzual & Charlot) a) 10 declining SFH SFR e-t/ =[0.1-30] Gyr tage=[50Myr-5 Gyr] tage<tuniv(z) 0 < E(B-V) <0.5 b) 1 constant SF Used Bands 6 SUBARU bands K band (CFHT) 4 Spitzer/IRAC 24m Spitzer/MIPS Red/Purple: Galaxy template Blue: AGN template (Merloni, Bongiorno et al. 2010 ApJ 708, 137M)
BH accretion and star formation… at higher redshift • Computation of the BH Masses SED fitting M* (scaling relation) BH masses (150) ~1.5%Edd ~0.2%Edd ( Bongiorno, Merloni et al. in prep)
Using the sSFR to distinguish “old” and “young” galaxies (391) ~0.02%Edd ~0.6%Edd ( Bongiorno, Merloni et al. in prep)
Hopkins & Hernquist (2008):The bimodality comes from the evolution of the triggering rates (mergers) in combination with a luminosity dependent AGN lifetimes. Using the sSFR to distinguish “old” and “young” galaxies Dotted lines: [OIII] completeness limit Gradual trend towards lower Eddington ratios with older stellar population content. However … selection effect still to be fully accounted for… ( Bongiorno, Merloni et al. in prep)