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)