X-ray astronomy 2008, Granada X-ray surveys of AGN: results and perspectives Andrea Comastri INAF-Osservatorio Astronomico Bologna R. Gilli (INAF-BO), A. Marconi (UniFI), C. Vignali (UniBO), K. Iwasawa (INAF-BO), M. Brusa (MPE), F. Civano (CfA), F. Fiore (INAF-Roma), E. Lusso (UniBO) and many others May 30, 2008 X-ray astronomy 2008, Granada

WHAT HAVE WE LEARNED FROM X-RAY SURVEYS (1)? Few keV (< 5) XRB mostly resolved into AGN Unobscured and Compton Thin fairly sampled X-rays detect more AGN than optical Compton thick AGN are being found (@z ~2) (Georgantopoulos, Fiore talks ) Rapid evolution up to a Lum. Dep. redshift (z ~ 1 for Seyferts z ~ 2-3 for QSO) (many talks) High redshift QSO (Brusa, Brandt talks) May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada WHAT HAVE WE LEARNED (2)? Type 2/1 fraction decreases with LX (Della Ceca) The type 2/1 fraction increases with z (?) (La Franca) AGN Host galaxy colors and morphologies (Mainieri) AGN-Host Galaxy co-evolution (Silverman) AGN trace the underlying LSS (Gilli) AGN responsible for quenching SF and accretion (Laird) … May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada Outline Original driver (resolve the XRB…) obscured AGN Census of SMBH (both in terms of accreted mass and emitted radiation) --> AGN evolution Luminosity and redshift dependence of obscuration Compton Thick AGN or the “holy grail” of X-ray surveys “Mildly” Compton Thick ( T ~ 1-3), “Heavily” ( T > 3 ) Compton Thick, “Ultra”-Thick” ( T >> 3), almost fully covered obscured AGN, … Missing sources or missing XRB (wild speculations…) Future perspectives Special Contents May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada X-ray spectra Unabsorbed: logNH<21 Compton-Thin: 21<logNH<24 (plus Compton Reflection & scattering) Compton-Thick: logNH>24 (T = 1 NH ~ 1.5 1024) Mildly (log NH=24-25) (NGC 6240, Circinus) Heavily (log NH >25) T >> 1 (NGC1068) May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada XRB The XRB synthesis provides an integral constraint (Gilli, AC, Hasinger 07) Red -> unobscured Blue -> Compton Thin Black -> Compton Thick The evolution is folded with the adopted XLF Obscured fraction (also for mildly and Heavily CT is Lum. Dep.) 4:1 log LX ~ 42 1:1 log LX ~ 46 May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada DOWNSIZING La Franca+05 ; Ueda+03 2-10 keV surveys Hasinger+05 0.5-2 keV surveys ~ 1000 sources May 30, 2008 X-ray astronomy 2008, Granada

Fraction of absorbed sources: Luminosity dependence Hasinger et al. 2005 (see also La Franca +05, Treister+05, Della Ceca+08) Black: X-ray Hasinger 2008 Green: IR Maiolino et al. 2007 Red: Optical Simpson et al. 2005 Della Ceca+08 Treister+08 Powerful AGN clean their sight-lines more rapidly than low luminosity AGN, and therefore the fraction of obscured AGN can be viewed as a measure of the timescale over which the nuclear feedback is at work. fraction of obscured AGN is a strong function of L: most luminous, less obscured Same result in DIFFERENT bands despite the very different selections!! May 30, 2008 X-ray astronomy 2008, Granada

Fraction of absorbed sources: Redshift dependence La Franca+05 La Franca +05 Hasinger 08 The most luminous objects reached the peak in their number density at earlier times (higher redshift) and declined faster than low-luminosity objects. Similar trends have been unveiled for the galaxy population and represent a challenge to current models of structure formation. “downsizing scenario” Luminosity effects observed fit in “downsizing” scenario more debated! Seen in (some) data [e.g. La Franca+05, Treister+06, Hasinger08], not seen in others (Ueda+03, Dwelly&Page 2006), not needed in XRB models (Gilli+07) but expected/predicted in feedback models (Menci+08) May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada Open Questions How do the present observations constrain the current SMBH-galaxy Coevolution paradigm ? Virtually all massive galaxies host an AGN (all galaxies experienced AGN) Magorrian relation MSMBH/Mbulge ~ 0.001 AGN feedback switch off SF and subsequent accretion It is matter of timescales (different phases) sub-mm galaxies (Alexander+05; Page talk) Downsizing , luminosity & redshift dependence of obscured fraction (most likely related to mass and accretion rates) Quantitative link with host galaxy properties (mass, SF, etc) Was the Magorrian relation already in place at high-z ? Do we see feedback in action ? (cold/thick and/or warm absorbers) Compton Thick are likely to provide further hints (Daddi+07; Fiore+08) May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada Selection of type-2 AGN at high z with MIPS/IRAC (Martinez-Sansigre+05-06;Alonso-Herrero+06; Polletta+06, Lacy+04; Stern+05; Daddi+07; Fiore+08a,b) Stack in the GOODS fields BzK selected Starforming galaxies R - K > 4.5 MIR(24)/O > 1000 May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada High Redshift Compton Thick Daddi + 07 L X > 1042 Fiore+07 L X > 1043 L X > 1044 Polletta+06 Martinez-Sansigre+06 L X > 1045 CT follows the same LDDE ev, Alexander+08 Fiore+08 May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada The Soltan argument BH c2 = (1-)/ * UT UT = ∫dt ∫Lbol F (Lbol) dLbol Bolometric UT = kbol∫dt ∫LX F (LX) dLX XLF UT = kbol 4  I0 / C * ( 1 + <z>) XRB UT --> Comoving AGN energy density --> Accretion efficiency I0 --> XRB energy density Kbol --> X-ray Bolometric correction Fabian & Iwasawa 99; Yu & Tremaine 02; Elvis+02; Marconi+04; Shankar+08; … May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada COSMOS Broad band SED ox ~ 1.4 x ~ 0.65 LBOL ~ 2 x 1046 erg/s Luminosity dependent KBOL OX is lum. Dep. Vignali+03; Steffen+06 Lusso, AC et al May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada Relic BH Mass Density BH c2 = (1-)/ * UT UT = ∫dt ∫Lbol F (Lbol) dLbol Bolometric UT = kbol∫dt ∫LX F (LX) dLX XLF UT = kbol 4  I0 / C * ( 1 + <z>) XRB Assume XLF, Bolometric correction and obscured AGN LF Require consistency with local value (MBH - Mbulge - ) 3-5 x 105 MSUN Mpc-3 (Salucci+99; Yu Tremaine 02; Marconi+04; … ) (8 x 104 MSUN Mpc-3 unobscured QSO optical LF in 1982) Continuity equation (differential) - Marconi+04 May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada The “only free” parameters are the accretion efficiency and Eddington ratio L = ε dM/dt c2 L = λ Ledd Good agreement  ~ 0.06-0.1 ~ 0.3-0.4 Marconi+04 Shankar+08 May 30, 2008 X-ray astronomy 2008, Granada

Radiative Efficiency and Eddington ratio Need to account for SMBH missed by X-ray surveys Compton Thick (XRB models) They come in at least two different “flavours” XRB constrain the mildly (possibly not uniquely … ) CT space density degenerates with geometry of reflecting matter 2% 10% 0.5% The higher the average scattering/ reflection intensity, the lower the number of sources, the higher the mass which goes into the BH, the lower the accretion efficiency  (and viceversa) May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada Beyond Compton Thick UT = U0 * kBOL * (1 + f(NH)) XLF approach, f(NH) Gilli+07 kBOL Marconi+04, lum. Dep. (1 - ) /  * (1 + Rthin+ RMthick + RHthick (0.02/f)) Luminosity dep. Constant (~150 for HL, ~ 50 for LL assuming  ~ 0.06 kBOL lum. Dep. & a “local” mass density of …) How many ultra-thick ( >> 1) and/or highly covered (f -> 0 or almost 4) AGN can be fit in without violating the mass constraints ? (1 - E)/E * (1 +  Rmodel + kE/kBOL* RE) KE E Bolometric correction and accretion efficiency of Enshrouded May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada Assume e = 0.1 then KE / KBOL * R ~ from 2 to 7 (Luminosity dependent) If KE ~ KBOL then the putative population of completely enshrouded AGN (X-ray quiet) maybe as numerous as the obscured AGN population If e ~ 0.3 even much more abundant (!) They radiate in the mid-far Infrared Depending from the column density and covering factor they may belong to the Daddi+07 / Fiore+08 samples May raise the SMBH contribution to the IR Background May 30, 2008 X-ray astronomy 2008, Granada

Mildly CT nearby galaxies AC+07 (astro-ph/0704.1253) SUZAKU OBSERVATION OF Mildly CT nearby galaxies AC+07 (astro-ph/0704.1253) Scattering fraction < 0.5 % NGC5728 Scattering fraction ~ 2% Ueda+07 Mushotzky talk NGC4992 May 30, 2008 X-ray astronomy 2008, Granada

 < 0.1 Slowly rotating BH ? ≈ 0.9 Stacking in the COSMOS ~ 54,000 counts ~ 1.58 +- 0.04 EW (6.4 keV) ~ 90 eV ≈ 0.2-0.4 Iwasawa+08 in prep ≈ -0.1 Miniutti , Longinotti, Nandra .. talks May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada More peaked Narrower redshift distr.? Different sources ? (see Gandhi+08) Difference spectrum CT from GCH07 EC = 200 keV INTEGRAL results De Rosa May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada Brusa,AC,Gilli+08 Gilli poster I5 May 30, 2008 X-ray astronomy 2008, Granada

Summary/Perspectives Aim to have “SDSS statistic” in the X-ray to put SMBH light up and evolution in a full context A truly multiwavelength approach is mandatory Obscured SMBH may come in different flavours they could also be X-ray quiet XRB set a “very useful” integral limit but cannot by itself breaks the parameter degeneracy Ultra deep XMM / Chandra and deep XEUS fields will reveal heavily obscured SMBH up to high redshifts Hard X-ray (10-100 keV) imaging (i.e. SimbolX; NexT XEUS) May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada Chandra 2 Ms (aim at ~ 6 Ms) 10-17 cgs over 50 arcmin2 XMM 1.3 Ms (aim at ~ 3 Ms) Confusion limited > 5 keV Luo+08 May 30, 2008 X-ray astronomy 2008, Granada

X-ray astronomy 2008, Granada September 7-11 , 2009 BOLOGNA - ITALY Aula Magna S. Lucia X-ray Astronomy 2009 : Present status, multi- approach and future perspectives Third in a decadal series of X-ray astronomy conferences in Bologna, this meeting will highlight the contribution of XMM-Newton and Chandra observatories, ten years after their launch. Emphasis will be given on cosmic sources multiwavelength studies and associated synergies with major facilities at all wavelengths, and on the perspectives for future high energy astrophysics missions. May 30, 2008 X-ray astronomy 2008, Granada