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The Bright Side of the X-ray SkyThe XMM-Newton Bright Survey
R. Della CecaT. Maccacaro
A. Caccianiga
P. Severgnini
V. Braito
INAF – Osservatorio Astronomico
di Brera,Milan
On behalf of the XMM-Newton Survey Science Centre
The XMM-Newton Bright Survey Project
The XMM Bright Survey is aimed at
selecting and spectroscopically identifying
a large and statistically representative
sample of bright (fx > ~7x10-14 c.g.s)
serendipitous XMM sources in the
0.5-4.5 keV energy band: Bright Sample (BS)
4.5-7.5 keV energy band: Hard Bright Sample (HBS)
Primary Selection Camera: the MOS2 detector
• Bright Sample (BS): CR (0.5-4.5 keV) > 0.01 s-1 (~7x10-14 cgs)
• Hard Bright Sample (HBS): CR (4.5-7.5 keV) > 0.002 s-1 (~7x10-14)
Criteria for ...
• Galactic latitude (|bII|>20); • Line of sight NH (<1021 cm-2);• Target confined within the
central chip;• Exposure time > 5 (-7) ks
to guarantee a flat sensitivity;
• Other (i.e. no very bright optical obj. in field, etc..)
• Source position: RI<R<RO
RI depending on
target/mode
RO =13'
• Avoid edges & gaps;
• No physical relation to
target
Primary Selection Camera: the MOS2 detector
Source selectionField selection
Among the scientific goals of the project are
• identifying X-ray “bright” sources suitable for detailed multi-wavelength follow-up studies;
• defining statistical identification procedures to select rare and interesting populations of X-ray sources (e.g. Type 2 QSO, absorbed AGNs);
• complementing medium and deep surveys to obtain a better coverage of the LX- z plane for statistical and evolutionary studies and to testcurrent AGN and XRB synthesis models.
Note that unlike deep/pencil beam surveys the XMM BSS is protected against problems connected to the cosmic variance
BS HBS
• Images used: 237 (211)
• Area Covered: 28.1 (25.17) sq.deg
• Total Source Sample 400
Sources in the Bright Sample: 389
Sources in the Hard Bright Sample: 67
(56 sources are in common)
The XMM-Newton Bright Survey Project
The XMM BSS in a context
Adapted fromBrandt and Hasinger, ARAAA, 2005, in press
XMM-Newton Bright Survey
The XMM BSS in a contextChandra , XMM
Deep Medium HEAO 1ASCABeppoSAX
XMM BSS 10 meters class telescope
4 meters class telescope
Adapted from Akiyama et al., 2003
Broad Line AGNs
Photometric z + X + etc..
X-ray spectral analysis is possible for almost all the sources in the XMM BSS!!
BS HBSSources 389 67Identified 311 (80%) 62 (90%)
Optical identification & classification(217 src our own spectroscopy + literature)
2%
1%
2%
16%
10%
69%
Broad Line AGN
Narrow LineAGN
Optically"Normal"Galaxy
Clusters ofGalaxies
BL Lac Objects
Stars
2%
2%
2%
3%
29%
62%
Broad Line AGN
Narrow LineAGN
Optically"Normal"Galaxy
Clusters ofGalaxies
BL Lac Objects
Stars
BS HBS
Extragalactic LogN - LogS
“hard” bright samplebright sample
AXIS (0.5-4.5 keV)
From ROSAT (0.5-2.0 keV)
From EMSS (0.3-3.5 keV)
XMM BSS
XMM BSS
From HELLAS(5-10 keV)
From HELLAS2XMM (5-10 keV)
From Lockmann Hole (5-10 keV)
Broad Band Properties of the
Sample
X-ray/optical flux ratio vs. HR2
“hard” bright samplebright sample
23
232
CRCR
CRCRHR
++++−−−−====Energy bands:
2) 0.5 - 2.0 keV; 3) 2.0 - 4.5 keV
CXB CXB
23
232
CRCR
CRCRHR
++++−−−−====
34
343
CRCR
CRCRHR
++++−−−−====
Energy bands:2) 0.5 - 2.0 keV3) 2.0 - 4.5 keV4) 4.5 - 7.5 keV
Hardness ratios
“hard” bright samplebright sample
CXB CXB
X-ray/optical flux ratio vs. 2-10 keV flux
“hard” bright samplebright sample
13% with X/O>10: Type 1 + Type 2 17% with X/O>10: Type 1 + Type 2
R=21 R=21
OPTICAL VERSUS X-RAY ABSORPTION
Optically type 1:Sy1 & QSO
NLSy1
Optically type 2:Sy2, QSO 2 & NELG
Sy1.9
Type 2 QSO
Exception
HBS 28 Sample (18h < RA < 5h) - 100% spectr. Id.)Caccianiga et al., 2004, A&A, 416, 901.HARDNESS-RATIOS
Sy 1 & QSONLSy1Sy2, QSO 2 & NELGSy1.9
23
232
CRCR
CRCRHR
++++−−−−====
34
343
CRCR
CRCRHR
++++−−−−====
Energy bands:2) 0.5 - 2.0 keV3) 2.0 - 4.5 keV4) 4.5 - 7.5 keV
Are optical and X-ray absorption unrelated ?
A Guided Spectral Tour in
the BSS and HBSS Sample
XMM X-ray spectrum (MOS+pn):ΓΓΓΓ=2.1, nH=1.1x1023 cm-2
Scattered Fraction = 2%
L(2-10 keV, intrinsic) = 1x1044 cgs
A Type 2 AGNs in the HBSS sample
Optical spectrum
Z=0.146
XMM X-ray spectrum(MOS+pn):ΓΓΓΓ=1.9*, nH=2.5x1022 cm-2
L(2-10 keV, intr.) = 3x1044 cgs
Optical spectrum
A High-Luminosity Type 2 AGNs
Z=0.562
Caccianiga et al., 2004, A.A., 416,901
An Absorbed Type 1 AGNs
XMM X-ray spectrum (MOS+pn):Absorbed power-law model
ΓΓΓΓ=1.9, nH=4x1022 cm-2 :Fe line
L(2-10 keV, intrinsic) = 3x1043 cgs
Optical spectrum
z=0.185
A High luminous Type 2 AGN
XMM X-ray spectrum (MOS+pn):Absorbed power-law model
ΓΓΓΓ=1.8, nH=3x1023 cm-2
L(2-10 keV, intrinsic) = 4x1045 cgs
Optical spectrum
z=1.154
MgII ?
A broad Line AGN with high X/0
XMM X-ray spectrum (MOS+pn):Absorbed power-law model
ΓΓΓΓ=2.0, nH=nHGal cm-2
L(2-10 keV, intrinsic) = 5x1044 cgs
Optical spectrum
z=0.465
AGN 2 UNABSORBED IN THE X-RAY
XMM-Newton MOS+pn
Γ=2.09 [1.95-2.20]NH<1.3x1020 cm-2
(Nhgal=2.5x1020 cm-2)
ESO3.6m/EFOSC2Sy1.9 (broad Hα)
Z=0.162
Caccianiga et al., 2004, A.A., 416,901
(R ≥≥≥≥ 24.5)
FF(2(2--10)10)≈≈≈≈≈≈≈≈1010--1313 cgscgsFxFx/Fo>/Fo>220220
K’ K’ ≈≈≈≈≈≈≈≈ 1919.5.5 magmag,, RR--K K ≥≥≥≥ 55
X-ray image
(0.5 - 4.5 keV)
Optical image (DSS)
R band image
K band image
A source with a very high X/0 ratio
ERO
FxFx/Fo>/Fo>220220 zz≈≈≈≈≈≈≈≈2.02.0
Fx
Fx /Fo
/Fo
(Fiore (Fiore etet al. 2003)al. 2003)
QSO2 CANDIDATEQSO2 CANDIDATE
ΓΓΓΓΓΓΓΓ=2, =2, NhNh=6=6x10x102222 cmcm--22
LL(2(2--10)10)intrintr=5=5x10x104545 erg serg s--11
A source with a very high X/0 ratio
If Fe lineZ=2.27
Severgnini et al., 2005, A&A, submitted
A deeper look at the HBSS
Sample
Work in progress………
HBS SAMPLE: OPTICAL BREAKDOWN
Class Spectral type Number %extra
Type 1 Sey1+QSO+NLSy1 39 65%
Type 2 Sey2+Sey1.9+QSO2 18 30%
Galaxies Optically Normal 1
Clusters Clusters of Galaxies 1
Galactic Accreting Binary 2
Unid 5
HBSS Sample
>50% of the 2-10 keV XRB
is produced at z < 1
Ueda et al., 2003
Modified Unified Scheme:XRB history
Lx = 43 - 44.5
Type 1 AGNType 2 AGN
Redshift Distribution
Type 1 AGN: 39 objectsType 2 AGN: 18 objects
Luminosity Distribution
Ueda et al., 2003
Modified Unified Scheme:
Lx = 43 - 44.5
Type 1 AGNType 2 AGN
Type 2 QSOHBSS Sample
Type 1 AGN: 39 objectsType 2 AGN: 18 objects
7 Type 2 QSOs
LogN - LogS of Type 1 and Type 2 AGN
“hard” bright sample
Type 1 AGNType 2 AGN
Expected from the XRB
synthesis models Ueda
et al., 2003
~ 41%Type 2 QSOs 0.28±±±±0.15 deg-2
Consistent with preliminary results from Caccianiga et al., 2004
)%934(2 ±≈
TotalAGN
AGNType
Nh-Lx plane for Type 2 AGN
“hard” bright sample
Conclusions• We have defined a complete sample of 400
Bright X-ray Sources using XMMMedium-good quality X-ray data for the majority of sources
• The spectroscopic ID work is almost completedMedium-good quality optical dataWe are accumulating multi-wavelength informationfrom existing archives
• Interesting results and firm numbers are emerging from this projectUnabsorbed Type 2 AGN, Type 2 QSO, high X/O, RQ vs. RL AGN
Many of the results discussed here arereported in:
♦ “XMM-Newton observations reveal AGN in apparently normal galaxies” by Severgnini et al., 2003, A&A, 406,483
♦ “The XMM-Newton HBS28 sample: Studying the obscuration in hard X-ray selected AGNs” by Caccianigaet al., 2004, A&A, 416, 901
♦ “Exploring the X-ray Sky with the XMM-Newton Bright Serendipitous Survey” by Della Ceca et al., 2004, A&A,428, 383
u “XMM-Newton spectroscopy of an X-ray selected sample of RL AGNs” by Galbiati et al., 2004, A&A, 430, 927
u “An x-ray bright ERO with an extreme x-ray to optical flux ratio” by Severgnini et al., 2005, A&A, submitted