The X-ray view of absorbed The X-ray view of absorbed INTEGRAL AGNINTEGRAL AGN

A. De Rosa On behalf of the INTEGRAL/AGN survey team

The broad-band INTEGRAL AGN sample The broad-band INTEGRAL AGN sample (part of…)(part of…)

SourceSource TypeType z*z* Observations Observations exp(ks)exp(ks)

IGR J12391-1610 Sy2 0.037 INTEGRAL/Chandra 200/3.2IGR J07565-4139 Sy2 0.021 INTEGRAL/Chandra 968/3.2IGR J12026-5349 Sy2 0.028 INTEGRAL/Chandra 728/3.2NGC 788 Sy2 0.014 INTEGRAL/ASCA 594/40ESO 103-G35 Sy2 0.013 INTEGRAL/XMM 44/12IC 4518A Sy2 0.016 INTEGRAL/XMM 898/11.5IGR J10404-4625 Sy2 0.024 INTEGRAL/XMM 626/13IGR J18027-1455 Sy1 0.035 INTEGRAL/XMM 2024/17LEDA168563 Sy1 0.029 INTEGRAL/XMM 135/9IGR J07597-3842 Sy1.2 0.040 INTEGRAL/XMM 837/13ESO 209-12 Sy1.5 0.040 INTEGRAL/XMM 936/20FRL 1146 Sy1.5 0.031 INTEGRAL/XMM 1041/5(16)4U 1344-60 Sy1.5 0.0129 INTEGRAL/XMM 1042/25IGR J16482-3036 Sy1 0.0313 INTEGRAL/XMM 1723/7IGR J16558-5203 Sy1.2 0.0054 INTEGRAL/XMM 1509/6IGR J17418-1212 Sy1 0.0372 INTEGRAL/XMM 1274/12 …. .. … …. …

From Bassani et al. 2006. and no more from XMM-AO6 large program . (*) optical spectroscopy, Masetti et al. 2006

We applied in XMM AO7 to observe 22 AGN We applied in XMM AO7 to observe 22 AGN selected at E>10 keV by INTEGRAL to finally selected at E>10 keV by INTEGRAL to finally

build a complete sample of 70 AGN in 0.2-200 keVbuild a complete sample of 70 AGN in 0.2-200 keV

Sample selectionSample selection

● Absorbed objects i.e. NH>1022 cm-2

● Type 2 AGN with F(20-100 keV) < 5 mCrab● X-ray data available (XMM/Chandra/ASCA)● We excluded sources with broad-band data already

studied by BeppoSAX● One well known source was retained (even if already

studied by BeppoSAX) as a posteriori check for our analysis taht is affected by limitation of using non simultaneous X and soft-gamma rays measurements

Our sample is representative of the populations of type 2 AGN observed by INTEGRAL above 10 keV

Our small Type 2 AGN sampleOur small Type 2 AGN sample

Source Source Type z Observations Type z Observations exp(ks) Flux*exp(ks) Flux*

LEDA170194 Sy2 0.03 INTEGRAL/Chandra 200/3.2 4.0

IGR J07565-4139 Sy2 0.021 INTEGRAL/Chandra 968/3.2 1.1

IGR J12026-5349 Sy2 0.028 INTEGRAL/Chandra 728/3.2 3.3

NGC 788 Sy2 0.014 INTEGRAL/ASCA 594/40 1.4

ESO 103-G35 Sy2 0.013 INTEGRAL/XMM 44/12 7.9

IC 4518A Sy2 0.016 INTEGRAL/XMM 898/11.5 2.9

IGR J10404-4625 Sy2 0.024 INTEGRAL/XMM 626/13.5 2.5

* In 2-10 keV. In 10-11 cgs

Broad band observations are a powerful and unique tool to Broad band observations are a powerful and unique tool to investigate the physics geometry of Innermost regions of AGNinvestigate the physics geometry of Innermost regions of AGN

Spectral slope and high energy cut-off: , Ec

Absorption: NH

type 2 vs type 1 objects

Nature/geometry of the absorbing gas

Iron line together with the Compton reflection hump: EW, R,AFe

CXRB synthesis

study

Nature/geometry of the reflecting gas

Compton thick vs Compton thin sources

Soft X-ray excess: kT, Asc/AIC

Thermal vs scattered scenario

Geometry at few Rg from the SMBH: AD? WSM?

IGR J10404-4625

Hard-X/soft-gamma components● Absorbed power-law + Fe K line● Absorbed power-law + Ecut-off + Fe K line● Absorbed power-law+Ecut-off+Reflection+Fe K line

Soft X-rays component● Thermal emission● Scattered power-law

Spectral analysis. Spectral analysis. Broad-band fitBroad-band fit

The absorptionThe absorption● The spectra of all sources are absorbed at low energies

from a gas with column density in the range (4-40)1022 cm-2. This suggests/confirms a Compton thin nature for the sources.

● Other indicators of thick absorption support this evidence (e.g. FX/F[OIII] and X/FIR)

● We associated the absorption medium with the molecular torus

The Compton reprocessing components:The Compton reprocessing components: I. The Reflection Hump I. The Reflection Hump

•For NH ~1023-1024-1025 cm-2 the contribution of the torus at the flux at 30 keV is 8, 29 and 55 per cent respectively (Ghisellini et al. 1994).

•Value of R higher than 2 can be 2 “real” or due to low flux state of the source or miscalibration between X-ray and gamma-ray instruments

•Cross-calibration constant measuerments on stable source (Crab) suggests C=1 at 20 keV for INTEGRAL/XMM-Chandra-ASCA (Kirsch et al. 2005)

Test the correlation between the photon index and R as proposed by Zdziarski et al. (1999) .. hard to check! Possible with the larger sample

Correlation factor r=0.0709

SAX average values

Is the absorbing gas able to produce the observed reflection hump?

The Compton reprocessing components:The Compton reprocessing components: II. II. The iron lines observationsThe iron lines observations

The lines are due to cold iron and with narrow profile <0.3 keV

If the line is produced far away the central source (TORUS?), at higher NH the continuum photons will be absorbed BUT not the line photons => increasing the EW

The NH values we found are in 4-40 1022 cm-2 would produce EW(Fe)=10-200 eV.

SAX

SAX

The origin of the Compton reflection featuresThe origin of the Compton reflection features

Question: Is this component produced in the absorbing medium? R and EW are too high to be produced in the absorber with the measured NH

Solution: the absorber is not homogeneous and the thick medium covers a large fraction of the solid angle but not the line of sight (already proposed by Risaliti et al. 2002). Clumpy torus

The alternative scenario: a grazing incidence of the intrinsic continuum on the inner edge of the torus: the high-energy photons

The sketch: a “grazing incidence” reflectionThe sketch: a “grazing incidence” reflection

Reflected

continuum

& Fe line

Comptonized continuum

Cold thick disctorus =100

scattered-thermal

component

NLR

The intrinsic continuum: The intrinsic continuum: vs vs EcEc●All the values of Ec we measure (even if lower limits) suggest that this feature is a common property of Seyfert galaxies.

●In a pair of AGN the photon index is flatter than the average observed in Seyfert. Also including type 1 INTEGRAL AGN (Panessa et al. 2007). This evidence can be or “real” (as expected in the CXRB synthesis model, Gilli et al. 2007) or to the presence of complex absorption

SAX

NGC 788

IC 4518A

An anti-correlation between photon index and Ec is expected in a Comptonizzation model (Haardt et l. 1997).. hard to check. Possible with larger sample and deep observations

II. Gradual upward curvature emerging below 4-5 keV BUT they are two peculiar case:

Starburst

SXV/SiXIV line

I. Sharp increase below 1-2keV

The soft X-ray excessThe soft X-ray excess

High resolution X-ray spectroscopy (HETG-LETG/Chandra and RGS/XMM) associated this component to photoionization of the NLR by the primary continuum (Bianchi et al. 2006) or thermal component due to starburst.

Thermal component: kT=0.2-0.9 keV - Scattered component:ASC/AIC fews%We observe different behaviour of the unabsorbed component

ConclusionsConclusions All the object show significant cold absorption NH>1023 cm-2 in good

agreement with the optical classification. All the sources are Compton thin (as confirmed by the ratio FX/[OIII]). We associated the absorber to the torusCompton reprocessing components (R & Fe line) tell us that the reflection/absorbing medium can be one and the same even if with some particular constraint (not homogeneous, grazing incidence)... but variability studies can help to investigate a different scenario: R vs flux relation. Link the iron line properties with the reflectionThe value of the high energy cut-off we found suggests that it is a common property of Type 2 AGN

...but correlations gamma vs flux, gamma vs Ecut-off have to be checkWe detect a soft excess in all the source. The origin seems to be different in different sources: photoionized plasma and/or warm scattering medium

What we need now?What we need now?

• Spend substantial amount of the INTEGRAL program on

extragalactic field. This will allow to build a larger

sample to search for correlations We stress that in 3th/2th

IBIS ratio of detected AGN is ~2…

•Variability studies (that we completely miss in this

analysis) need very deep INTEGRAL observations joint

to multi-wavelength campaign with XMM (hoping to

have success with the large program as proposed),

Chandra and Swift.