the chandra survey of the cosmos field fabrizio fiore & the c-cosmos team particular thanks to...
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The Chandra survey of the The Chandra survey of the COSMOS fieldCOSMOS field
The Chandra survey of the The Chandra survey of the COSMOS fieldCOSMOS field
Fabrizio Fiore & the C-COSMOS teamFabrizio Fiore & the C-COSMOS team
Particular thanks to Particular thanks to T. Aldcroft, M. Brusa, N. Cappelluti, T. Aldcroft, M. Brusa, N. Cappelluti, F. CivanoF. Civano, A. Comastri, , A. Comastri,
M. Elvis, M. Elvis, S. Puccetti, C. VignaliS. Puccetti, C. Vignali, G. Zamorani, G. ZamoraniM. Salvato & S-COSMOS teamM. Salvato & S-COSMOS team
& many others& many others
Table of contentTable of content
Presentation of the survey C-COSMOS in a context Selected scientific results
Close pairs High-z QSOs Fraction of obscured AGN
Summary (what you should bring home after all..)
Multiwavelength coverage is mandatory X-ray is the leading band for all AGN studies
(provided that X-ray coverage is deep enough)
Presentation of the survey C-COSMOS in a context Selected scientific results
Close pairs High-z QSOs Fraction of obscured AGN
Summary (what you should bring home after all..)
Multiwavelength coverage is mandatory X-ray is the leading band for all AGN studies
(provided that X-ray coverage is deep enough)
The C-COSMOS survey: which science
The C-COSMOS survey: which science
Black hole growth and census XMM has ~20% of ambiguous identifications. Chandra survey secures the
discovery and identifications of rare objects (elusive AGN, high-z AGN).
The combination of Chandra data and Spitzer’s 24m and 3-8 m data allows us to unveil highly obscured accretion, thus providing a complete census of accreting SMBH
The influence of the environment on galaxy activity excesses of X-ray point sources (AGN) within a few Mpc of clusters at
0.2<z<1.
spikes in the redshift distribution of the X-ray sources The AGN and galaxy ACF and CCF down to a few arcsec: how the
AGNs trace the cosmic web. AGN pairs with separation<10-20”: galaxy activity vs. galaxy interaction
Black hole growth and census XMM has ~20% of ambiguous identifications. Chandra survey secures the
discovery and identifications of rare objects (elusive AGN, high-z AGN).
The combination of Chandra data and Spitzer’s 24m and 3-8 m data allows us to unveil highly obscured accretion, thus providing a complete census of accreting SMBH
The influence of the environment on galaxy activity excesses of X-ray point sources (AGN) within a few Mpc of clusters at
0.2<z<1.
spikes in the redshift distribution of the X-ray sources The AGN and galaxy ACF and CCF down to a few arcsec: how the
AGNs trace the cosmic web. AGN pairs with separation<10-20”: galaxy activity vs. galaxy interaction
The C-COSMOS survey: howThe C-COSMOS survey: how The Chandra high resolution permits to resolve sources 2”
apart over 0.9 sq. deg., corresponding to 8-16 kpc separations for z = 0.3-0.9, and locates point sources to < 4 kpc at any z. Thus close mergers can be resolved, and AGNs can be distinguished from ULXs and off-nuclear starbust.
Thanks to the good PFS, ACIS-I is not background limited, then C-COSMOS reaches ~3 times deeper than XMM-COSMOS in both hard and soft bands and cross the threshold where starburst galaxies become common in X-rays.
The low ACIS background enables stacking analysis, in which counts at the positions of known classes of objects are co-added to increase the effective exposure time
The Chandra high resolution permits to resolve sources 2” apart over 0.9 sq. deg., corresponding to 8-16 kpc separations for z = 0.3-0.9, and locates point sources to < 4 kpc at any z. Thus close mergers can be resolved, and AGNs can be distinguished from ULXs and off-nuclear starbust.
Thanks to the good PFS, ACIS-I is not background limited, then C-COSMOS reaches ~3 times deeper than XMM-COSMOS in both hard and soft bands and cross the threshold where starburst galaxies become common in X-rays.
The low ACIS background enables stacking analysis, in which counts at the positions of known classes of objects are co-added to increase the effective exposure time
C-COSMOS in a contextC-COSMOS in a contextHST ACS imaging HST ACS imaging with resolution 0.05” and sensitivity 27.2 mag (10 ) provides morphologies of over 2 milions galaxies at < 100 pc resolution!
IR/Optical/UV large surveys to improve photometric redshift
Spitzer: IRAC-deep
MIPS-Shallow
MIPS-Deep
Optical spectroscopy surveys: zcosmoszcosmos:540 hours on the ESO VLT using VIMOS. Magellan COSMOS
VLA-Cosmos Large Project plus submm
XMM-NewtonXMM-Newton: 1.4 Msec.
Chandra!Chandra!
Cycle 8 proposal•1.8 Msec•200ksec•0.9sq.deg
•flim ~2x 10-16 cgs (0.5-2 keV)
40
arcmi
n
52
arcmin
z = 0.73 structure
z-COSMOS faint
Color: XMM first year
Full COSMOS field
C-COSMOS: numbersC-COSMOS: numbers 1.8 Ms total exposure time 36 ACIS-I pointings 200 ksec average exposure
0.5deg2
100 ksec average exposure 0.4deg2
Flim~2x10-16 cgs (0.5-2 keV) 1759 X-ray sources
(probability threshold 2x10-5)
1.8 Ms total exposure time 36 ACIS-I pointings 200 ksec average exposure
0.5deg2
100 ksec average exposure 0.4deg2
Flim~2x10-16 cgs (0.5-2 keV) 1759 X-ray sources
(probability threshold 2x10-5)
Elvis et al. 2008
The C-COSMOS multiwavelenth catalog
The C-COSMOS multiwavelenth catalog
Identification in the 3.6micron K, and I bands using a statistical method to match the X-ray error box to the most likely cp (“likelihood ratio technique”) “identification” in 3 bands
sample: 94% !! IR “identified” sample 5%
most interesting sources high-z QSOs, obscured QSOs
ambiguous/unidentified sample 1%
870 sources in common with XMM 895 NEW sources!!
450 spectroscopic redshift already in hand(SDSS,VIMOS,IMACS)
Photometric redshift already available for 60% of the sample
Identification in the 3.6micron K, and I bands using a statistical method to match the X-ray error box to the most likely cp (“likelihood ratio technique”) “identification” in 3 bands
sample: 94% !! IR “identified” sample 5%
most interesting sources high-z QSOs, obscured QSOs
ambiguous/unidentified sample 1%
870 sources in common with XMM 895 NEW sources!!
450 spectroscopic redshift already in hand(SDSS,VIMOS,IMACS)
Photometric redshift already available for 60% of the sample
Obscured AGN
unobscured AGN
SFgalaxiesXBONGs
Star
Extreme AGN 5%
XMM-COSMOSlimit on 1deg2
Civano et al 2008
Close pairsClose pairs
•Thanks to the good Chandra PSF it is possible to study close pairs to search for X-rays from galaxy interactions.•Wavelet detection algorithm (PWDETECT, Damiani et al.) optimized to resolve nearby sources (Puccetti et al. 2008). • A total of 106 sources closer than 12” are present in the X-ray catalog. > than expected from simulation.•Next step is to obtain the spectroscopic identification to verify the fraction of physical pairs (Vignali et al. 2008)
Chandra/XMM comparisonChandra/XMM comparison
• 50% of the chandra pairs have associated only one XMM 50% of the chandra pairs have associated only one XMM source. In several cases the brightness of the sources of the pair source. In several cases the brightness of the sources of the pair is similar.is similar.
BLUE circles= 0.5-7 keV chandra detections. Green =XMM contours
High redshift AGNHigh redshift AGN
C-COSMOS XMM-COSMOSElvis et al. 2008 Brusa et al. 2008Civano et al. 2008
•XMM-COSMOS: •QSO z>3 ~30 deg2
•QSO z>4 ~3 deg2
• Chandra ~3 times deeper than XMM
•100-200 QSO z>3 deg2
•10-20 QSO z>4 deg2
Obscured AGNObscured AGN
Chandra U ACS K 3.6m 4.5m
Type 1 AGNNon type 1 AGN MIR/O>1000
High X/O, high MIR/O
AGN densityAGN density
43-44
44-44.5
44.5-45.5
>45.5
42-43
La Franca, Fiore et al. 2005Menci, Fiore et al. 2008
Paucity of Seyfert like sources @ z>1 is real? Or, is it, at least partly, a selection effect?
Are we missing in Chandra and XMM surveys highly obscured (NH1024 cm-2) AGN? Which are common in the local Universe…
Paucity of Seyfert like sources @ z>1 is real? Or, is it, at least partly, a selection effect?
Are we missing in Chandra and XMM surveys highly obscured (NH1024 cm-2) AGN? Which are common in the local Universe…
Why multiwavelength surveysWhy multiwavelength surveys
IR surveys: AGNs highly
obscured at optical and X-ray wavelengths shine in the MIR thanks to the reprocessing of the nuclear radiation by dust
IR surveys: AGNs highly
obscured at optical and X-ray wavelengths shine in the MIR thanks to the reprocessing of the nuclear radiation by dust
Dusty
torus
Central engine
Use both X-ray and MIR surveys:
Select unobscured and moderately obscured AGN in X-rays
Add highly obscured AGNs selected in the MIR
Simple approach: Differences are emphasized in a wide-band SED analysis
Use both X-ray and MIR surveys:
Select unobscured and moderately obscured AGN in X-rays
Add highly obscured AGNs selected in the MIR
Simple approach: Differences are emphasized in a wide-band SED analysis
Why multiwavelength surveysWhy multiwavelength surveys
MIR selection of CT AGNMIR selection of CT AGN
ELAIS-S1 obs. AGN ELAIS-S1 24mm galaxies HELLAS2XMMCDFS obs. AGN
Fiore et al. 2003
Open symbols = unobscured AGN Filled symbols = optically obscured AGN * = photo-z
Unobscured obscured
X/0
MIR/O
MIR selection of CT AGNMIR selection of CT AGN
COSMOS X-ray COSMOS 24um galaxies
R-K
Fiore et al. 2008a Fiore et al. 2008b
Open symbols = unobscured AGNFilled symbols = optically obscured AGN* = photo-z
CDFS X-rayHELLAS2XMM GOODS 24um galaxies
COSMOS MIR AGN COSMOS MIR AGN
Fiore et al. 2008b
Stack of Chandra images of MIR sources not directlynot directly detected in X-rays
AGN fractionAGN fraction
Chandra survey of the Bootes field (5ks effective exposure) Brand et al. 2006 assume that AGN populate the peak at F24um/F8um~0 only. They miss a large population of obscured AGN, not detected at the bright limits of their survey.
CT AGN volume densityCT AGN volume density
A
BC
GCH 2007 logNH>24
z=1.2-2.2: density IR-CT AGN ~ 45% density X-ray selected AGN, ~90% of unobscured or moderately obscured AGNz=0.7-1.2: density IR-CT AGN ~ 100% density X-ray selected AGN, ~200% of unobscured or moderately obscured AGNThe correlation between the fraction of obscured AGN and their The correlation between the fraction of obscured AGN and their luminosity holds luminosity holds including CT AGN,including CT AGN, and it is in place by z~2 and it is in place by z~2
No AGN feedback AGN feedback
Gilli et al. 2007 model
La Franca et al. 2005
Density of Obscured AGNsDensity of Obscured AGNs
Dashed lines = Menci model, no AGN feebackSolid lines = Menci model, AGN feedback 2-10 keV data = La Franca, FF et al. 2005
Spectroscopic confirmation: very difficult for the CDFS-GOODS sources (R~27, F(24um)~100uJy
Possible for the COSMOS sources!! F24um~1mJy ==> Spitzer IRS AO5 program (Pri. C, Salvato et al.)
? ?
SummarySummary Chandra sensitive survey of the COSMOS field: 1758
sources, ~half new, I.e. not detected by XMM ~100 sources with optical counterpart fainter than I=26.5:
==> highly obscured QSOs, high-z QSOs Large sample of bright pairs: ==> galaxy interaction vs. galaxy activity Combined use of Chandra and Spitzer over a large field: Combined use of Chandra and Spitzer over a large field:
==> discovery of CT type 2 QSOs at z=1-2==> discovery of CT type 2 QSOs at z=1-2 ==> fraction of X-ray detected and X-ray emitting AGN in ==> fraction of X-ray detected and X-ray emitting AGN in
24um samples is large (~50%)24um samples is large (~50%) All this will allow a precise determination of the evolution of
the accretion in the Universe, a precise census of accreting SMBH
While multiwavelength coverage is mandatory, X-ray is the leading band for AGN studies (provided that X-ray coverage is deep enough)
Chandra sensitive survey of the COSMOS field: 1758 sources, ~half new, I.e. not detected by XMM
~100 sources with optical counterpart fainter than I=26.5: ==> highly obscured QSOs, high-z QSOs
Large sample of bright pairs: ==> galaxy interaction vs. galaxy activity Combined use of Chandra and Spitzer over a large field: Combined use of Chandra and Spitzer over a large field:
==> discovery of CT type 2 QSOs at z=1-2==> discovery of CT type 2 QSOs at z=1-2 ==> fraction of X-ray detected and X-ray emitting AGN in ==> fraction of X-ray detected and X-ray emitting AGN in
24um samples is large (~50%)24um samples is large (~50%) All this will allow a precise determination of the evolution of
the accretion in the Universe, a precise census of accreting SMBH
While multiwavelength coverage is mandatory, X-ray is the leading band for AGN studies (provided that X-ray coverage is deep enough)