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X-ray view of the most obscured QSOs at high redshift Chiara Feruglio CNRS - CEA, Saclay

X-ray view of the most obscured QSOs at high redshift Chiara Feruglio CNRS - CEA, Saclay IRAM - Institut de RadioAstronomie Millim etr ique  thanks to: Daddi, Fiore, Piconcelli, Alexander, Malacaria, Puccetti et al. IXO science meeting, Roma, 14 March 2011.

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X-ray view of the most obscured QSOs at high redshift Chiara Feruglio CNRS - CEA, Saclay

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  1. X-ray view of the most obscured QSOs at high redshift Chiara Feruglio CNRS - CEA, Saclay IRAM - Institut de RadioAstronomie Millimetrique  thanks to: Daddi, Fiore, Piconcelli, Alexander, Malacaria, Puccetti et al. IXO science meeting, Roma, 14 March 2011

  2. Why highly obscured, Compton thick, high luminosity AGN are so important: • They can be witnesses of a crucial phase in the AGN/galaxy coevolutionary sequence, an evolutionary scenario led by galaxy interactions (& mergers): • Obscured, rapid growth of both central SMBH and galaxy (high SF) • Onset of AGN feedback, through powerful winds major mergers galaxy-galaxy interactions • AGN power heats and expells the ISM in the disk, quenching star-formation [Silk & Rees 98, Di Matteo+ 05, Croton+ 06, King 05 Hopkins +08, Somerville+ 08, Menci +08, Catteneo+08] The phase of highly obscured, intrinsecally luminous QSO hosted in powerful SF galaxies should be the best to catch AGN feedback

  3. A spectacular example: QSO feedback in Mrk 231 The nearest (z=0.042, 187Mpc) QSO • Lbol=2 1046 erg/s • highly obscured, NH~1024 cm-2 • loBAL with winds arising from the BLR • expanding bubbles on kpc scales seen by HST • hosted in a ULIRG with SFR ~200 MSun/yr (late stage merging system) Braito+2004 Lipari+09 Goal : detect the outflow of the cold molecular gas in the QSO host

  4. QSO feedback revealed in Mrk 231 (Feruglio et al. 2010) IRAM-PdBI detection of broad CO(1-0) CO(1-0) Broad CO(1-0) CO(1-0) @115.2712 GHz Narrow component + low surface brightness broad component with wings extending out to +-800 km/s (FWZI = 1500 km/s). OUTFLOW RATE dM(H2)/dt = 700 M ⊙ /yr Wings are spatially resolved and extended on 1.2 kpc scales. SFR ~ 200M⊙ /yr Kinetic energy of outflowing gas: E =1.2 1044 erg/s = ~1% LBol (2 1046 erg/s) Map of Blue wing Map of Red wing expected for AGN radiation driven shock-wave expanding in the ISM (Lapi+05)

  5. Mrk 231 massive, Kpc-scale molecular outflow Confirmed by Herschel... (Fischer et al. 2010) The P-Cygni profiles of the OH 119 μm and 18OH 120 μm OH 79 μm blue-shifted lines confirm the OUTFLOW with vel ~1400 km/s. ... and recently confirmed by IFU spectroscopy (Rupke+2011) Neutral gas absorption traces 2-3 Kpc scale outflow with v ~ 1100 km/s powered by the AGN Are SMBH/galaxy rapid obscured growth and QSO feedback common at z~2 ? peak of AGN & SF activity

  6. Gilli et al. 2007 Finding the most obscured, missing BH at high z • Finding highly obscured & Compton thick AGNs is extremely challenging because of • Obscuring column NH > 1024 cm-2 • but crucial for: • the hard X-ray background • feedback on SF • BH mass-bulge relation • Recent discovery of very large gas reservoirs in high-z massive galaxies support rise in average NH (hence, in very obscured system) (Daddi et al. 2009, Tacconi et al. 2010) Highly obscured AGN

  7. Finding the most obscured, missing BH • IR selection of candidate highly obscured AGN, missed by hard X-ray surveys: • objects with mid-IR excess (Daddi+07) • obj bright in the mid-IR and faint in the optical (DOGs, Fiore+08,09, Martinez-Sansigre 2005) • Power-law SED in the IR (Lacy+2004, Polletta+2006, Donley+2008) X-ray stacking shows that a large fraction hosts highly obscured AGN. However, only X-ray observations can confirm the AGN nature of these sources, by estimating obscuration and the intrinsic AGN power. mid-IR excess DOGs power-law SED

  8. Compton thick AGN in the local universe Circinus galaxy Only few dozen objects known even locally Fe Kwith high EW (>1 keV) on flat continuum is the hallmark of Compton thick obscuration NH > 1.5 1024 cm-2 Guainazzi+2005 Fukazawa+2010

  9. Gilli+2011 @z = 4.76 stacked Compton thick AGN in the distant universe a type 2 QSO at z=3.71 in CDFS (Norman et al. 02; 2) Confirmed recently by Comastri et al. 2011 (XMM survey of CDFS, 3 Ms) Deep X-ray observations confirm a few CThick at high z with • Fe K 6.4 keV with EW > 1 keV • flat spectrum Georgantopoulos+09, 6 CThick in CDFN, Fe K

  10. Discovery of CThick QSO in two BzK galaxies at z~2.5-3 Feruglio, Daddi, Fiore, Alexander, Piconcelli & Malacaria, 2011 Based on the 4 Msec Chandra data of CDFS BzK4892 zspec=2.578 Fe Kα (6.4 keV) > 4σ detection EW=2.3 -0.6+1 keV zspec=2.578 EW(Fe Kα) = 2.3 keV ==> COMPTON THICK QSO , NH>>1024 cm-2 L(2-10 keV) ~1044.5 erg/s, most likely 1045 erg/s derived from Fe Kα, mid-IR , optical lines

  11. Discovery of CThick QSO in two BzK galaxies at z~2.5-3 Feruglio, Daddi, Fiore, Alexander, Piconcelli & Malacaria, 2011 BzK8608 zphot=2.9 Fe Kα 3σ detection with EW=1.2 ± 0.4 keV zphot=2.9 Compton-thick QSO, NH> a few 1024 Lx ~ 1044 erg/s

  12. spectro-z Fe K redshift constraint vs optical redshift constraint photo-z • FeK might be a useful tool (for future missions) • to measure redshifts of the most obscured systems • z/1+z ~ 0.02 (1)

  13. The SF host galaxies of Compton thick QSOs Highly obscured QSO hosted in highly star forming, dust obscured galaxies ACS ACS • Mid-IR excess (x6), • U-band drop-out • SFR ~70 MSun/yr from UV • SFR ~300 MSun/yr from Radio • no Herschel detection • Extreme mid-IR excess (x170), • DOG, F(24um) = 591 uJy • U-band drop-out • SFR ~70 MSun/yr from UV • SFR ~1100 MSun/yr from Radio (VLA) SFR ~500 MSun/yr from Apex-Laboca 870 um • detected by Herschel PACS+Spire • ACS morphology suggests merger, 2 blobs

  14. ERS+GOODS-MUSIC survey in the CDFS 4Msec exposure Compton thick AGN at z > 3 20-40keV ERS (FF+11) GCH 2007 Treister 2009 2-10 keV Chandra/XMM Large fraction of highly obscured AGN at z > 3 (3/17) in CDFS 4Ms ERS survey (Fiore+2011). Fraction of CThick~17% at F(2-10)~0.3-3 10-16 cgs This is already ~ total CT fraction predicted by GCH2007. Fraction of CT at high-z may be higher than predicted before (similar result obtained by Gilli+ 2011) E537 L(2-0keV)=1043.8 erg/s E1577 L(2-10keV)=1043.6 erg/s E8579 L(2-10keV)=1043.5 erg/s Fiore+2011

  15. ERS+GOODS-MUSIC survey in the CDFS 4Msec exposure Gas-to-dust ratio of the absorbing matter ~ 1/100-1/1000 of the Galactic value. Compact absorber <1 pc smaller than dust sublimation radius (see eg. Shi+2006) or smaller dust content Filled:Point-like Open: extended Shi+2006 1/100 1/1000

  16. Density of CThick AGN • @z=1.4-3 and L(2-10keV) > 1044 erg/s: 3E-6 Mpc-3 ~1 in 80 arcmin2 • @z >3 and L(2-10keV) > 10 43.5 : ~ 1 in 25 arcmin2 • In WFI 18x18 arcmin FOV it means between 2-10 obj. per field NGC1068 Matt+2004 Simulated 100 and 500ks IXO/WFI spectra of ERS 537 and ERS 1577, assuming Fe Ka 6.4 keV, Fe He-like 6.7 keV and Fe H-like 6.9 keV as in NGC1068

  17. The IXO view of CThick QSOs • Simulated spectra of BzK4892 at z=2.578: • WFI in 100 ks make redshift of BzK-like objects z / 1+z ~ 0.01 (1 • - XMS: detects emission lines only: search for sharp concentration of photons in deep XMS fields A survey of 20 50/200ks fields would yield ~40 CThick with L(2-10keV) > 1044 erg/s at z<3 and ~160 with L(2-10keV)>1043.5 erg/s with spectra of quality similar or better to that available today with Chandra multiMsec exposures. Surprises from search of photon concentration in energy in deep XMS pointings

  18. Conclusions • Luminous CT AGN can be witnesses of crucial phase in AGN/galaxy co-evolution: onset of AGN feedback • Chandra provides today the best evidence for luminous CThick AGNs at high-z • Tip of the iceberg: Lx ~ 1044 erg/s for BzK4892 Strong Fe Ka (30 counts in the line, 80 total in 4Msec) • Lx>1043.5 erg/s CThick AGN and/or higher z are fainter but still feasible with Chandra (Gilli+2011, Fiore+2011). They are probably more common, 1-2 per WFI FOV.

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