obscured agn in the (z)cosmos survey agn9, ferrara, may 25 2010 angela bongiorno max-planck-institut...
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Obscured AGN in the (z)COSMOS survey
AGN9, Ferrara, May 25 2010
Angela BongiornoMax-Planck-Institut für extraterrestrische Physik, Garching, GERMANY
AND
Andrea Merloni
Marco Mignoli
Gianni Zamorani
Marcella Brusa
And
The COSMOS/zCOSMOS teams
Complete census of AGN (in particular obscured population)
How obscured AGN evolve
Fraction of obscured AGN (as a function of e.g. L and z)
Hie
rarc
hica
l gr
owth
Grow
th of SM
BH
Gas inflow
AGN feedback Active
Quasar
Starburst &buried Quasar
Normal galaxies
Galaxy mergers
(adapted from Hopkins et al., 2008)
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 HST
Spitzer
SubaruVLA
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
Chandra
SPECTRA: the z-COSMOS project
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
VIMOS @VLT
P.I. S. Lilly
zCOSMOS Institutes ETH Zurich
LAM Marseille
LAOMP Toulouse
INAF Milano
INAF Bologna
MPE Garching
VIMOS @VLT
[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
(Bongiorno, Mignoli, Zamorani et al., 2010 A&A 510, 56B)
Luminosity-dependent density evolution (LDDE)
1=2.13 2=0.5 L*=1.1 1041 *=2.55 10-5
Fraction of type-2 AGN
0.15< z <0.3 from ∼65% to ∼50% from L[O III]=106.2 -108.2 L to 108.2-109.2L
• at L[OIII] > Lc, decreasing fraction of type–2 AGN with luminosity
• What happen at L[OIII] < Lc?
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 ⊙
(Bongiorno, Mignoli, Zamorani et al., 2010 A&A 510, 56B)
SDSS (Reyes08)zCOSMOS
SDSS type-2 AGN sample @z<0.3 (Kauffmann & Heckman 2008)
BH accretion as a function of galaxy properties…
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.
~2% Edd
Eddington Log(L[OIII]/MBH) =1.7
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
• 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
Separate the Spectral Energy Distribution of AGN into nuclear+host components and derive the host properties
(Merloni, Bongiorno et al. 2010 ApJ 708, 137M)
Red/Purple: Galaxy templateBlue: AGN template
Used Bands6 SUBARU bands
K band (CFHT)4 Spitzer/IRAC
24m Spitzer/MIPS
SED fitting M* (scaling relation) BH masses
(150)
~1.5%Edd~0.2%Edd
( Bongiorno, Merloni et al. in prep)
BH accretion and star formation…at higher redshift
➤ Computation of the BH Masses
( Bongiorno, Merloni et al. in prep)
~0.6%Edd~0.02%Edd
Using the sSFR to distinguish “old” and “young” galaxies
(391)
( Bongiorno, Merloni et al. in prep)
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…