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Robust identification of distant Compton-thick AGNs IR AGN Optical AGN Need for deep optical-mid-IR spectroscopy: multiple lines of evidence for intrinsic.

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Presentation on theme: "Robust identification of distant Compton-thick AGNs IR AGN Optical AGN Need for deep optical-mid-IR spectroscopy: multiple lines of evidence for intrinsic."— Presentation transcript:

1 Robust identification of distant Compton-thick AGNs IR AGN Optical AGN Need for deep optical-mid-IR spectroscopy: multiple lines of evidence for intrinsic AGN luminosity can make a case for distant Compton-thick absorption Alexander et al. (2008) 1Ms simulated XEUS spectrum X-rays

2 Enhanced AGN Activity in a z=3.09 Protocluster David M Alexander, Bret Lehmer, Jim Geach (Durham) With Franz Bauer, Scott Chapman, Yuichi Matsuda, Ian Smail, Toru Yamada, amongst others

3 2 Ms CDF-N 5 ks NOAO DWFS Broad Range of blank-field X-ray Surveys Alexander et al. (2003) Murray et al. (2005) CDFN: L X ~3x10 40 erg/s at z~0.5; L X ~10 42 erg/s at z~2 (almost 100x deeper than Bootes but 100x larger) Brandt & Hasinger (2005) now also 2Ms!

4 Evolution of AGNs from blank-field surveys Ueda et al. (2003) Fiore et al. (2003) Hasinger et al. (2005) 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 But what causes this “AGN downsizing”? What “drives” the growth of black holes?

5 A key laboratory of black- hole growth mechanisms: a distant protocluster? 400ks Chandra exposure of SSA22 PI: D.M. Alexander z=3.09 SSA22 protocluster Predicted to become a massive Coma-like cluster by the present day The galaxy density is ~6x higher than the field already at z~3.09

6 First insight into AGN activity in a Distant Protocluster Lehmer, Alexander, et al., in prep Many more obscured quasars in protocluster (400ks; blue) than found in field (2Ms; red) at z~3 Bret Lehmer

7 Enhanced black-hole growth compared to the field But is the shift in the x-axis or the y-axis? LBGs LAEs AGN fraction suggestively larger than found in the field (by a factor of ~3.4) Lehmer, Alexander, et al., in prep

8 Shift may be in the x-axis: larger black holes? Implication: the characteristic X-ray luminosity and “active” black-hole mass may be a function of environment as well as redshift Steidel et al. (2005) Steidel found that galaxies in a z=2.3 protocluster are more massive: if the same is found in SSA22 then this may imply that the black holes are larger

9 Role of Environment? 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 Yamada et al., in prep LAE density image

10 Extended lyman-alpha outflows: AGN or star-formation powered? Geach, Alexander, et al., in prep Jim Geach Do outflows forge this M-sigma relationship? Mbh/Msph~10 -3 Lyman-alpha outflow: PKS1138-262 radio gal z=2.16 5/29 extended lyman- alpha objects are X-ray detected: considerably higher source density than radio galaxies

11 Lower luminosity (but much more typical) AGN outflows than found in radio galaxies? 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 Geach, Alexander, et al., in prep High-z radio gals IFU constraints on outflow kinematics of PKS1138-262 Nesvadba et al. (2006)

12 Summary 400ks Chandra observation of z=3.09 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 >1 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? Compton-thick AGNs are very difficult to identify in the local Universe let alone at z~2: detailed observations are required to identify individual sources to strengthen the case for the “missing” distant Compton-thick AGN population

13 Role of Environment: Blank-field Surveys? 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 >10 objects/bin>10000 AGNs AGNs from COSMOS compared to galaxies from GOODS Lehmer & Alexander

14 Prospects for a Wide-Area XMM Proposal? Cosmological simulation of z~1 regions in 2 sq deg field

15 The Wide-Deep XMM-Newton Survey Proposal 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/cm 2 ; f(2-10keV)~3x10 -15 erg/s/cm 2 Sensitivity limits: 1.6x10 43 erg/s (rest-frame 4-20 keV) at z~1; about order of magnitude higher at z~3 (trace AGN “downsizing”) 3 Ms Proposal Failed Last Round: to give 10 sq deg at 50ks Source Statistics: ~10000 X-ray AGNs; ~1000 with >100 counts (basic X-ray spectra) ~500 z>3 quasars (obscured and unobscured) and ~10 at z>6 ~100-150 Compton-thick AGNs (ID’d from SEDs) ~80-160 X-ray starbursts ~300-400 clusters (~30 with M>10 14 solar masses; ~20-30 at z>1) Many possible science goals


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