obscured and unobscured growth of super-massive black holes
DESCRIPTION
Obscured and unobscured growth of Super-massive Black Holes. Francisco J. Carrera, X. Barcons, J. Bussons, J. Ebrero, M. Ceballos, A. Corral (IFCA, CSIC-UC, Spain) & XMM-Newton Survey Science Centre (S. Mateos, M. J. Page, M.G. Watson, J. Tedds, R. Della Ceca ...). - PowerPoint PPT PresentationTRANSCRIPT
Obscured and unobscured growth of Super-massive Black Holes
Francisco J. Carrera, X. Barcons, J. Bussons, J. Ebrero, M. Ceballos, A. Corral (IFCA, CSIC-UC, Spain)
&XMM-Newton Survey Science Centre
(S. Mateos, M. J. Page, M.G. Watson, J. Tedds, R. Della Ceca ...)
Extragalactic X-ray Surveys, Boston, November 6, 2006
Resolving the X-ray background:An XMM-Newton International
Survey (AXIS)
Definition of the AXIS survey (Carrera
et al 06) • 36 XMM-Newton target fields:
– Galactic latitude |b|>20 deg– X-ray observations with EPIC-pn
detector in FULL-FRAME-MODE– ~Avoided fields with bright and/or
extended targets– Good time intervals > 10 ksec– Available early on in the mission
• Solid angle ~4.8 deg2
• Using SAS v6.1.1 to produce final source list and products: – Exposure and background maps– Source detection– Spectra and calibration matrices
• Areas around target + OOT+ near the pn CCD gaps excluded
• Own empirical sentitivity maps from detected source parameters
• Very detailed source screening• Total of 1433 distinct X-ray
sources with detection likelihood >15 in any of 4 bands (see below)
NGC4291
Mrk 205
Soft0.5-2 keV
XID0.5-4.5
keV
Hard2-10 keV
Ultrahard4.5-7.5 keV
X-ray source counts (XMM-Newton & Chandra & ASCA)
The contribution to the X-ray background
ShallowMediumDeep Surveys
Medium surveysresolve the
brightest50% of the
X-raybackground
The XMM-Newton Medium Survey(XMS)
The XMS samples (Barcons et al.
07)
Name Band (keV)
Flux limit 10-14 cgs
# sources(unique)
# identified (fraction)
Soft XMS-S
0.5-2 1.5 210 (1) 200 (95%)
Hard XMS-H
2-10 3.3 159 (20) 132 (83%)
XID XMS-X
0.5-4.5 2.0 284 (56) 261 (92%)
Ultrahard XMS-U
4.5-7.5 - 70 (2) 60 (86%)
• Subset of AXIS:– 25 fields chosen for follow-up: 3.3 deg2
– Flux limited in Soft, Hard and XID
Optical identification of the XMS
• Optical imaging: g,r,i (SDSS), Z (Gunn), mostly at the INT/WFC to r~23-24mag
• Reliable & unique candidate counterpart in r/i for virtually all sources (< 5” or < 5)
• Optical spectroscopy– 50% from AXIS programme (WHT, TNG, NOT):
multi-fibre and long-slit spectroscopy– 20% from Calar Alto/3.5m long-slit spectroscopy– 15% from VLT/FORS2 long-slit spectroscopy– A few from AAT/2dF, SUBARU/FOCAS, and others
• Preliminary results from 2 XMM-Newton fields (~30 sources) in Barcons et al (2002)
The content of the XMS
10
12
14
16
18
20
22
24
26
28
0,1 1 10 100
0.5-4.5 keV flux / 10-14 erg cm-2 s-1
r o
r i o
r R
BLAGN
NELG
Gal
Star
Unid
4m spec lim
10m spec lim
Deep Medium Shallow
Breakdown of identified sources
XMS-S Soft
XMS-H Hard
XMS-X XID
XMS-U Ultrahard
Broad-line AGN
75% (148/200)
63% (83/132)
73% (190/261)
65% (39/60)
Narrow-line galaxies (AGN)
13% (27/200)
27%(35/132)
15% (39/261)
27% (16/60)
Absorption line galaxies+clust
4% (8/200)
7% (9/132)
4% (10/261)
5% (3/60)
Stars 8% (15/200)
2% (3/132)
8% (20/261)
0% (0/60)
Redshift distributionXMS-S
0
5
10
15
20
25
30
35
0 1 2 3 4
z
Nu
mb
er
Soft
XMS-H
0
2
4
6
8
10
12
14
16
18
0 1 2 3 4
z
Nu
mb
er
Hard
Peak of QSO distribution(z~1.5) well sampled.
Obscured population outto z~1 in Hard sample
Luminosities and redshiftsXMS-S
41
42
43
44
45
46
47
0 1 2 3
z
log
L (0.5
-2 k
eV
)
XMS-H
41
42
43
44
45
46
47
0 1 2 3
z
log
L (2-1
0 k
eV
)
Soft
Hard
QSO-2 @ z=2.2
All galaxies consistentwith hosting AGN
LX>1042 erg/s
QSOs
“Seyferts”
Tips for statistical identification
~90% Obscured AGN
90% unobscured AGN
Stars
HR2
log
(FH
ard
/Fop
t)
Obscured and Unobscured AGN
X-ray to optical ratio:
a marker for obscuration?
Soft•5% of sources with fX/fopt>10•30% of fX/fopt>10 obscured AGN
FX/Fopt >10
Hard
log
(FH
ard
/Fop
t)
•15% of sources with fX/fopt>10•~70% of fX/fopt>10 obscured AGN
log
(FS
oft/F
op
t)
FX(10-
14cgs)
FX(10-14cgs)
Optical colours
QSOsS+Irr
E+S0
10% of QSOsare red
QSOsS+Irr
E+S0
HardSoft
r-i
g-r g-r
#
Reddening
Fainter X-ray sources are redder?
FHard(10-14cgs)
r-i
Optical versus X-ray “colours”: Hard
Hard Softer
Harder sources are >90% obscured AGNSofter sources: Optically blue: unabsorbed AGN Optically red: mix of abs & unabs AGN
HR2
g-r
X-ray absorption vs obscuration: not equivalent
The XMS survey
•10% of type 1 AGN are absorbed(with NH<1022 cm-2) •>40% of type 2 AGN are absorbed
Mateos et al (2005)
The Lockman Hole survey
•15% (<30% at 3) of type 1 AGN are absorbed (with NH<1022 cm-2) •80% (>50% at 3) of type 2 AGN are absorbed. But 5/28 are unabsorbed
Mateos et al (2006)
Stacking analysis
• Procedure still being tested• Selecting X-ray spectra with >80cts• Unfolding with best fit Gal+Intrinsic abs. p.l.• Correcting for Galactic NH
• De-redshifting• Renormalizing using flux in 2-8 keV band• Averaging in final bins (≥500 cts)• Averaging AXIS:
– BLAGN (200 sources)– NELG (43)
• Much improved averaging AXIS+XMM-2dF (see Xu, Mateos):– BLAGN (549): =1.95±0.02 Fe line @6.5±0.2 keV EW=130±60 eV – NELG (113): =1.53±0.02 Fe line @6.6±0.4 keV EW=130±100 eV
AXIS+XMM-2dFBLAGN
AXIS+XMM-2dFNELGs
Averaging X-ray spectraCorral et al., in preparation
Conclusions
• On-going work• Brightest 50% of the X-ray background dominated by AGN.• Unobscured accretion dominates, but increasingly
important contribution from obscured objects.• X-ray absorption and optical obscuration not
equivalent:– 10% of type 1 AGN are X-ray absorbed– 15% of type 2 AGN are not X-ray absorbed
– 25% of fX/fopt>10 hard X-ray sources are type 1 AGN
– 10% of X-ray selected type 1 AGN have red colours
• Even at medium fluxes, an important fraction of the X-ray sources have optically faint and red optical counterparts.
• Most unIDed objects faint (r/i>21.5) and extended: NELGs• Preliminary results from average spectra show Fe lines
in both BLAGN and NELGs