WHAT HAVE WE LEARNED FROM X-RAY SURVEYS (1)?

May 30, 2008 May 30, 2008 X-ray astronomy 2008, GranadaX-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

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


WHAT HAVE WE LEARNED FROM X-WHAT HAVE WE LEARNED FROM X-RAY SURVEYS (1)?RAY SURVEYS (1)?

Few keV (< 5) XRB mostly resolved into AGNFew keV (< 5) XRB mostly resolved into AGN Unobscured and Compton Thin fairly sampledUnobscured and Compton Thin fairly sampled X-rays detect more AGN than optical X-rays detect more AGN than optical Compton thick AGN are being found (@z ~2) Compton thick AGN are being found (@z ~2)

(Georgantopoulos, Fiore talks )(Georgantopoulos, Fiore talks ) Rapid evolution up to a Lum. Dep. redshift (z ~ 1 for

Seyferts z ~ 2-3 for QSO) (many talks)(many talks) High redshift QSO High redshift QSO (Brusa, Brandt talks)(Brusa, Brandt talks)


WHAT HAVE WE LEARNED (2)?WHAT HAVE WE LEARNED (2)?

Type 2/1 fraction decreases with LType 2/1 fraction decreases with LX X (Della Ceca) (Della Ceca) The type 2/1 fraction increases with The type 2/1 fraction increases with z (?) z (?) (La Franca) (La Franca) AGN Host galaxy colors and morphologies AGN Host galaxy colors and morphologies (Mainieri) (Mainieri) AGN-Host Galaxy co-evolution AGN-Host Galaxy co-evolution (Silverman)(Silverman) AGN trace the underlying LSS AGN trace the underlying LSS (Gilli)(Gilli) AGN responsible for quenching SF and accretion AGN responsible for quenching SF and accretion (Laird)(Laird) ……


OutlineOutline Original driver (resolve the XRB…) obscured AGN Original driver (resolve the XRB…) obscured AGN Census of SMBH Census of SMBH (both in terms of accreted mass and (both in terms of accreted mass and

emitted radiation)emitted radiation) --> AGN evolution --> AGN evolution Luminosity and redshift dependenceLuminosity and redshift dependence of obscurationof obscuration Compton Thick AGN or the Compton Thick AGN or the “holy grail”“holy grail” of X-ray surveys of X-ray surveys ““Mildly”Mildly” Compton Thick ( Compton Thick ( TT ~ 1-3 ~ 1-3), ), “Heavily” (“Heavily” ( TT > 3 ) > 3 )

Compton Thick, Compton Thick, “Ultra”-Thick” (“Ultra”-Thick” ( TT >> 3 >> 3), almost fully ), almost fully covered obscured AGN, …covered obscured AGN, …

Missing sources or missing XRB (wild speculations…) Missing sources or missing XRB (wild speculations…) Future perspectives Future perspectives Special Contents Special Contents


Unabsorbed:logNH<21Compton-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)

X-ray spectraX-ray spectra


XRB

The XRB synthesisprovides an integralconstraint(Gilli, AC, Hasinger 07)

Red -> unobscured

Blue -> Compton Thin

Black -> Compton Thick

The evolution is foldedwith the adopted XLFObscured fraction (also for mildly and Heavily CT is Lum. Dep.)4:1 log LX ~ 42 1:1 log LX ~ 46


DOWNSIZING La Franca+05 ; Ueda+032-10 keV surveys

Hasinger+05 0.5-2 keV surveys

~ 1000 sources


Fraction of absorbed Fraction of absorbed sources: Luminosity sources: Luminosity

dependencedependence

fraction of obscured AGN is afraction of obscured AGN is a strong function of Lstrong function of L: : most luminous, less obscured most luminous, less obscured

Same result in DIFFERENT bandsSame result in DIFFERENT bands despite the very despite the very different selections!!different selections!!

Hasinger et al. 2005

(see also La Franca +05, Treister+05, Della Ceca+08)

Black: X-ray Hasinger 2008

Green: IRMaiolino et al. 2007 Red: Optical Simpson et al. 2005

Della Ceca+08 Treister+08


Fraction of absorbed Fraction of absorbed sources: Redshift sources: Redshift

dependencedependence

more debated!more debated! Seen in (some) dataSeen in (some) data [e.g. La Franca+05, Treister+06, [e.g. La Franca+05, Treister+06,

Hasinger08],Hasinger08], not seen in othersnot seen in others (Ueda+03, Dwelly&Page 2006),(Ueda+03, Dwelly&Page 2006), not needed in XRB modelsnot needed in XRB models (Gilli+07)(Gilli+07) but expected/predicted but expected/predicted in feedback modelsin feedback models (Menci+08)(Menci+08)

La Franca +05 Hasinger 08La Franca+05


Open Questions 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)


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)

BzK selectedStarforming galaxies

R - K > 4.5MIR(24)/O > 1000

Stack in the GOODS fields


High Redshift Compton Thick Daddi + 07

L X > 1042

Fiore+07L X > 1043

L X > 1044

Martinez-Sansigre+06L X > 1045

Polletta+06

Alexander+08 Fiore+08

CT follows the same LDDE ev,


The Soltan argumentThe Soltan argumentThe Soltan argumentThe Soltan argumentBH 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 densityKbol --> X-ray Bolometric correction

Fabian & Iwasawa 99; Yu & Tremaine 02; Elvis+02; Marconi+04;Shankar+08; …


COSMOS Broad band SED COSMOS Broad band SED

Lusso, AC et al

ox ~ 1.4 x ~ 0.65LBOL ~ 2 x 1046 erg/s

Luminosity dependent KBOL

OX is lum. Dep. Vignali+03; Steffen+06


Relic BH Mass DensityRelic BH Mass DensityRelic BH Mass DensityRelic BH Mass DensityBH 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


The “only free” parameters The “only free” parameters are the accretion efficiency are the accretion efficiency and Eddington ratioand Eddington ratio

L = L = εε dM/dt c dM/dt c22

L = L = λλ L Leddedd

Good agreementGood agreement ~ 0.06-0.1~ 0.06-0.1 ~ 0.3-0.4~ 0.3-0.4

Marconi+04Marconi+04Shankar+08 Shankar+08


Radiative Efficiency and Eddington Radiative Efficiency and Eddington ratioratio

2%

0.5%10%

CT space density degenerates with geometry

of reflecting matter

Need to account for SMBHmissed by X-ray surveysCompton Thick (XRB models) They come in at least twodifferent “flavours”

XRB constrain the mildly(possibly not uniquely … )

The higher the average scattering/ reflection intensity, the lowerthe number of sources, the higher the mass which goes into the BH, the lower the accretion efficiency (and viceversa)


Beyond Compton ThickBeyond Compton ThickUT = 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


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


NGC5728 NGC5728

NGC4992 NGC4992

ScatteringScattering fraction ~ fraction ~ 2% 2%

Scattering fraction < Scattering fraction < 0.5 %0.5 %

SUZAKU OBSERVATION OFSUZAKU OBSERVATION OFMildly CT nearby galaxiesMildly CT nearby galaxies

AC+07 (astro-ph/0704.1253)AC+07 (astro-ph/0704.1253)

Ueda+07Ueda+07Mushotzky talkMushotzky talk


< 0.1 Slowly rotating BH ?< 0.1 Slowly rotating BH ?

Stacking in the COSMOS

~ 54,000 counts

~ 1.58 +- 0.04

EW (6.4 keV) ~ 90 eV

≈ 0.9

≈ 0.2-0.4

≈ -0.1

Iwasawa+08 in prep

Miniutti , Longinotti, Nandra .. talks


CT from GCH07EC = 200 keVINTEGRAL resultsDe Rosa

Difference spectrum

More peaked Narrower redshift distr.?Different sources ?(see Gandhi+08)


Brusa,AC,Gilli+08

Gilli poster I5


Summary/PerspectivesSummary/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)


Chandra 2 Ms (aim at ~ 6 Ms)

10-17 cgs over50 arcmin2

XMM 1.3 Ms(aim at ~ 3 Ms)

Confusion limited> 5 keV

Luo+08


X-ray Astronomy 2009 : Present status, multi- approach and future perspectives

September 7-11 , 2009 BOLOGNA - ITALY Aula Magna S. Lucia

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.

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WHAT HAVE WE LEARNED FROM X-RAY SURVEYS (1)?