Robust identification of distant Compton-thick AGNs

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Robust identification of distant Compton-thick
AGNs
IR AGN
Alexander et al. (2008)
Need for deep optical-mid-IR spectroscopy
multiple lines of evidence for intrinsic AGN
luminosity can make a case for distant
Compton-thick absorption
X-rays
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Enhanced AGN Activity in a z3.09 Protocluster
David M Alexander, Bret Lehmer, Jim Geach
(Durham) With Franz Bauer, Scott Chapman, Yuichi
Matsuda, Ian Smail, Toru Yamada, amongst others
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Broad Range of blank-field X-ray Surveys
Murray et al. (2005)
5 ks NOAO DWFS
now also 2Ms!
Brandt Hasinger (2005)
2 Ms CDF-N
CDFN LX3x1040 erg/s at z0.5 LX1042 erg/s at
z2 (almost 100x deeper than Bootes but 100x
larger)
Alexander et al. (2003)
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Evolution of AGNs from blank-field surveys
Ueda et al. (2003)
Hasinger et al. (2005)
But what causes this AGN downsizing? What
drives the growth of black holes?
Fiore et al. (2003)
Luminosity-dependent density evolution (LDDE)
high-luminosity AGNs (i.e., quasars, such as
those found by SDSS) peaked at higher redshifts
than more typical AGNs
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z3.09 SSA22 protocluster
A key laboratory of black-hole growth mechanisms
a distant protocluster?
400ks Chandra exposure of SSA22
Predicted to become a massive Coma-like cluster
by the present day
PI D.M. Alexander
The galaxy density is 6x higher than the field
already at z3.09
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First insight into AGN activity in a Distant
Protocluster
Bret Lehmer
Many more obscured quasars in protocluster
(400ks blue) than found in field (2Ms red) at
z3
Lehmer, Alexander, et al., in prep
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Enhanced black-hole growth compared to the field
LAEs
LBGs
Lehmer, Alexander, et al., in prep
But is the shift in the x-axis or the y-axis?
AGN fraction suggestively larger than found in
the field (by a factor of 3.4)
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Shift may be in the x-axis larger black holes?
Steidel found that galaxies in a z2.3
protocluster are more massive if the same is
found in SSA22 then this may imply that the black
holes are larger
Steidel et al. (2005)
Implication the characteristic X-ray luminosity
and active black-hole mass may be a function of
environment as well as redshift
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Role of Environment?
LAE density image
Yamada et al., in prep
Protocluster structure extends over 100 Mpc
region (1 deg) and has variations in galaxy
density require more X-ray observations to
explore the effect of galaxy density on enhanced
AGN activity
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Extended lyman-alpha outflows AGN or
star-formation powered?
Jim Geach
Geach, Alexander, et al., in prep
5/29 extended lyman-alpha objects are X-ray
detected considerably higher source density than
radio galaxies
Mbh/Msph10-3
z2.16
Lyman-alpha outflow PKS1138-262 radio gal
Do outflows forge this M-sigma relationship?
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Lower luminosity (but much more typical) AGN
outflows than found in radio galaxies?
IFU constraints on outflow kinematics of
PKS1138-262
High-z radio gals
Nesvadba et al. (2006)
Geach, Alexander, et al., in prep
Require high-quality integral field unit
observations (we have FLAMES observations in
optical) to spatially resolve kinematics and test
whether accretion-related outflows are a
widespread phenomena
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Summary

• Compton-thick AGNs are very difficult to
  identify in the local Universe let alone at z2
  detailed observations are required to identify
  individual sources to strengthen the case for the
  missing distant Compton-thick AGN population

• 400ks Chandra observation of z3.09 SSA22
  protocluster to explore AGN activity (black-hole
  growth) in an overdense environment a laboratory
  on what drives black-hole growth
• AGN fraction in galaxies higher than found in
  the field large fraction are obscured quasars -
  longer AGN duty cycle OR higher characteristic
  AGN luminosity than found in field (Lehmer et
  al.)?
• Some of the AGNs are associated with large-scale
  outflows (Ly-alpha) X-ray-Ly-alpha luminosity
  ratios similar to high-redshift radio galaxies
  but gt1 order of magnitude less luminous
  tentative evidence for accretion-related outflows
  in typical AGNs in the distant Universe (Geach
  et al.)?

• Require more extensive observations of SSA22 to
  explore wider role of environment (galaxy
  density) on AGN activity - is this the primary
  driver for black-hole growth?

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Role of Environment Blank-field Surveys?
Lehmer Alexander
AGNs from COSMOS compared to galaxies from GOODS
Need (1) large area (trace full range of
environments), (2) large number of sources
(explore the key parameters), and (3) good
sensitivity (to trace dominant AGN at each
epoch) e.g., 10 galaxy density bins, 5 redshift
bins, 5 luminosity bins, 2 large-scale structure
(clusters vs non clusters), and gt10
objects/bingt10000 AGNs
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Prospects for a Wide-Area XMM Proposal?
Cosmological simulation of z1 regions in 2 sq
deg field
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The Wide-Deep XMM-Newton Survey Proposal
3 Ms Proposal Failed Last Round to give 10 sq
deg at 50ks

• Survey Parameters
• 50 ks exp in 5 fields (9 pointings/sq deg) with
  IR-submm data (7.1 sq deg but total of 10 sq deg
  when combined with existing data)
• Wide RA range eases stress on XMM scheduling and
  follow-up
• f(0.5-2keV)5x10-16 erg/s/cm2
  f(2-10keV)3x10-15 erg/s/cm2
• Sensitivity limits 1.6x1043 erg/s (rest-frame
  4-20 keV) at z1 about order of magnitude higher
  at z3 (trace AGN downsizing)

• Source Statistics
• 10000 X-ray AGNs 1000 with gt100 counts (basic
  X-ray spectra)
• 500 zgt3 quasars (obscured and unobscured) and
  10 at zgt6
• 100-150 Compton-thick AGNs (IDd from SEDs)
• 80-160 X-ray starbursts
• 300-400 clusters (30 with Mgt1014 solar masses
  20-30 at zgt1)

Many possible science goals