HST Workshop Bologna Jan 31, 2008 Heavily obscured SMBH at high redshift Andrea Comastri INAF - OABologna C. Vignali, R. Gilli, K. Iwasawa, F. Civano, M. Brusa, N. Cappelluti,, F. Fiore, G. Zamorani, W.N. Brandt, X. Barcons, F. Carrera, F. Nicastro, V. Mainieri, H. Brunner, A. Merloni, J. Silverman, P. Rosati, S. Puccetti, P. Tozzi, I. Georgantopoulos

HST Workshop Bologna Jan 31, 2008 Outline Accreting SMBH represents a key ingredient of AGN/galaxy formation and co-evolution. AGN census and evolution (the search for the most obscured -Compton Thick- ones) The Ultradeep XMM - CDFS survey add spectral sensitivity to multi data HST after SM4 (WFC3 - IR channel) Host galaxies morphologies - high z (> 6) obscured QSO

HST Workshop Bologna Jan 31, 2008 AGN and galaxy co-evolution  Early on  Strong galaxy interactions= violent star-bursts  Heavily obscured QSOs  When galaxies coalesce  accretion peaks  QSO becomes optically visible as AGN winds blow out gas.  Later times  SF & accretion quenched  red spheroid, passive evolution  Early on  Strong galaxy interactions= violent star-bursts  Heavily obscured QSOs  When galaxies coalesce  accretion peaks  QSO becomes optically visible as AGN winds blow out gas.  Later times  SF & accretion quenched  red spheroid, passive evolution Most BH mass accreted during luminous AGN phases ! Most bulges passed a phase of activity

AGN hosts (mostly early type morphology) populate the red sequence and green valley AGN activity persist after SF has ended Many hard sources in the red sequence At variance with model predictions Mignoli+04 HELLAS2XMM Pozzi+07 See also Silverman+07 AGN hosts in the green valley

HST Workshop Bologna Jan 31, 2008 Evidences for missing SMBH Marconi+04/08 Gilli, AC, Hasinger 07 Compton Thick AGN are predicted to be as numerous as unobscured and less obscured AGN

HST Workshop Bologna Jan 31, 2008 Highly obscured AGN highly obscured at optical and soft X-ray wavelengths shine in hard X- rays and in the MIR (thanks to the reprocessing of the nuclear radiation by dust)

HST Workshop Bologna Jan 31, 2008  135 sources (out of 1729 with F 24 > 40  Jy)  22 detected by Chandra  =43.4+/-0.3, =22.9+/-0.8, ~2.1  LogF(1.5-4keV) stacked sources= logL obs (2-8keV) stacked sources ~41.8  log ~ 44.6 ==> logL(2-8keV) unabs.~43  Difference implies logNH > 24  135 sources (out of 1729 with F 24 > 40  Jy)  22 detected by Chandra  =43.4+/-0.3, =22.9+/-0.8, ~2.1  LogF(1.5-4keV) stacked sources= logL obs (2-8keV) stacked sources ~41.8  log ~ 44.6 ==> logL(2-8keV) unabs.~43  Difference implies logNH > 24 Fiore+08 “Mildly” CT AGN Absorption by CT gas may be key ingredient of feedback mechanism Daddi+07 IR-optical

HST Workshop Bologna Jan 31, 2008 CT AGN only barely sampled by deep Chandra and XMM surveys Relative fraction steeply increasing Hard (> 10 keV) surveys more efficient Redshift distribution ~ ~ X-ray

HST Workshop Bologna Jan 31, 2008 XMM Ultradeep field XMM simulation ~ 370 ks already available ~ 1.3 Ms in 2008 Aim at 3 Ms Chandra 2 Ms just completed (PI W.N. Brandt) Aim at 4-5 Ms

HST Workshop Bologna Jan 31, 2008 Optically faint/Undetected Rodighiero+07 Brusa, Fiore+08 Koekemoer+04 EXOs Candidate z > 6 More likely z~2-3

HST Workshop Bologna Jan 31, 2008 Host galaxy morphologies ACS cutouts of two Type 2 AGN in the z ~ 0.7 CDFS LSS Type 2 AGN at higher redshift Brusa,Fiore+08 Koekemoer+02 Grogin+03 Schreier+01

HST Workshop Bologna Jan 31, 2008 K K-band residuals after deconvolution without and with the central component Z ~ !!! Galaxy: J=16.52±0.01 K=15.25±0.01 AGN: J=20.30±0.35 K=18.09±0.10 Galaxy: J=16.92±0.05 K=15.21±0.01 AGN: J=20.75±0.29 K=18.39±0.24 K Host galaxy morphologies Civano+07

More than 100 obscured AGN (a few tens CT) will be discovered by XMM & Chandra ultra-deep CDFS surveys WFC3 - IR deep (AB ~ 28) high resolution observations Obscured AGN host galaxy morphologies Pick up faint red nuclei Red passive galaxy hosting dying SMBH ? The role of environment (i.e. z ~ 0.7) Is AGN feedback responsible of SF quenching ? Very faint or undetected --> very high-z AGN ? Summary