Hard X-ray selected sample of AGN: population studies

Transcription

1 Hard X-ray selected sample of AGN: population studies Angela Malizia

2 INCREASE OF AGN POPULATION IN THE INTEGRAL SURVEYS most of the unidentified objects have been subsequently classified as AGN Many more in the next IBIS survey

3 OUTLINES OF THIS TALK Which type of AGN? How hard X-ray surveys can help in understand their properties Which type of host galaxies? How hard X-ray survey can help in understand the link between AGN and host galaxy

4 AGN POPULATION VIEWED BY INTEGRAL Last INTEGRAL AGN cat (272 sources): Seyferts & Blazars from Malizia et al Blazar; 22 Other; 13 Sey 2; 105 Sey 1; 132

5 AGN population viewed by INTEGRAL not only Seyfert galaxies Few Liners, all with N H 22, none CT Also a few type 2 QSO 22.2 N H XBONG, 0.01 z 0.1, N H 23 All type of AGN observed in soft X-rays now seen above 20 kev

6 NOT ONLY BLAZAR BUT THE MOST EXTREME BLAZARS Hard X-rays allow the discovery of: 1) very high power objects, those having: IGR J z=3.7 more powerful jet more luminous accretion disks larger black hole masses MeV Compton peak but redshifted to hard X-ray domain Lanzuisi et al z>2 z>2 Above z=3, 8 detections now by BAT/IBIS against 4 by Fermi

7 Wolter et al EXTREME BLAZARS FOUND (SEE L. BASSANI TALK) 2) very LOW power objects, those having less powerful jet inefficient accretion disks IGR J =HESS J Hard X-ray Synchrotron peak 1H peak above 100 kev even if source in low flux state Szostek et al Compton peak at TeV domain Radio galaxies see Molina talk

8 The INTEGRAL sample: a powerful tool for AGN science Absorption studies Complete sample of AGN broad band spectral shape in type 1 & type 2 Contribution of AGN to the CXB

9 ABSORPTION PROPERTIES 48% of INTEGRAL AGN are absorbed and 7% are Compton Thick! Absorbed AGN: N H cm -2 Compton thick: N H T x cm AGN with secure optical classification and X-ray data (Malizia et al. 2012) BUT EVEN HARD X-RAY SURVEYS ARE BIASED!

10 ABSORPTION PROPERTIES Using a Complete sample of AGN, INTEGRAL for first estimate the TRUE FRACTION OF ABSORBED AND COMPTON THICK (Malizia et al. 2009) Range NH (Log) Flux Reduction Number missed % % % 12 Assuming Euclidean LogN-LogS Loss of about 15 CT objects (Malizia et al 2009) CT AGN 7% 21% IN THE COMPLETE SAMPLE

11 True Fraction of CT AGN confirmed by other studies Adopting a similar correction, also Burlon et al. (2011) found a fraction of CT AGN 20% using a BAT sample of AGN!! IR IRAS/12µ (Brightman & Nandra 2011) 20% Optical--Palomar ( Akylas & Georgantopoulos 2009) 15% Note that within Seyfert 2 population CT objects are in agreement with revised fraction of Risaliti et al. (1999)

12 True fraction of ABSORBED and COMPTON THICK Complete versus enlarged AGN sample 1) Fraction of abs AGN decreases with z 2) Heavily abs AGN now seen at higher z 3) True view of abs AGN only in first z bin Absorbed AGN 80% CT AGN 17±3 %

13 TRUE FRACTION OF ABSORBED AGN VS HARD X-RAY LUMINOSITY work in progress with F. La Franca et al. Using this large sample we have studied if the fraction of absorbed AGN changes with luminosities as observed at lower energies (La Franca et al. 2005). Note that this study for the first time takes into account the bias in z discussed before. MORE ABSORBED AGN AT LOW LUMINOSITIES

14 BROAD BAND SPECTRA OF THE COMPLETE SAMPLE - UPDATE - all type 2 had already good quality X-ray data (XMM-Suzaku-Chandra) [De Rosa et al. 2012] many type 1 only poor X-ray data (XRT) [Molina et al. 2009] we have now XMM data of all the type 1 plus we have added latest Swift/BAT to increase the statistics at high energy XMM IGR J IBIS BAT before (XRT+IBIS) now (XMM+IBIS+BAT) Γ soft (soft excess) N H (10 22 ) 1.06 ± ± 0.09 Γ hard 1.70 ± ± 0.09 E line ± 0.04 R NC <1.84 E C NC ~ 110

15 BROAD BAND SPECTRA OF THE COMPLETE SAMPLE Newton-XMM + INTEGRAL-IBIS +Swift-BAT NOT contemporaneous but cross correlations between instruments OK (see Molina et al updates, De Rosa et al. 2012, Molina et al. 2013) Great variety: extreme complexity with many components: 1. SOFT EXCESS Sy1 always present in Sy2, but in 6 objects is more complex than a scattered power law Sy2 present in a good fraction of Sy1, but dominates only in a few sources

16 BROAD BAND SPECTRA OF THE COMPLETE SAMPLE Complexity: 2. simple and/or complex absorption Absorption in type 2 AGN of the complete sample plus complex absorption in 25% of type 1 AGN: one or more layer of material partially covering the source OFTEN THIS COMPLEX ABSORPTION IS VARIABLE In agreement with results from the entire AGN sample (Malizia et al. 2012) Opt. type 1 Opt. type 2 Total Unabsorbed (52%) Absorbed (48%) Total 154 (57%) 118(43%) 272 IGR J

17 BROAD BAND SPECTRA OF THE COMPLETE SAMPLE Complexity: 3. iron line/s type 1 Kα line almost always present and generally narrow (σ<10 ev) A few broad Kα line observed in around 10% of both Sy1 and Sy2 15% of Sy1 require also a Kβ line type 2 Sy1 : EW=81 ev (σ=50 ev) Sy2 : EW=490 ev (σ=670 ev) Sy2(No CT) : EW=306eV (σ=565 ev) no CT

18 BROAD BAND SPECTRA OF THE COMPLETE SAMPLE PRIMARY PHOTON INDEX now measured type 1 & type 2 the same type 1: <Γ>=1.74 (σ=0.18) Γ flatter than canonical 1.9 but OK with CAIXA sample Type 2: <Γ>=1.70 (σ=0.27) Large spread

19 BROAD BAND SPECTRA OF THE COMPLETE SAMPLE REFLECTION also estimated not easy to constrain: complexity, variability, modelling type 1: <R>=1.47 (σ=0.87) type 2: <R>=1.69 (σ=1.27)

20 BROAD BAND SPECTRA OF THE COMPLETE SAMPLE CUT-OFF: located type 1: <E c >=126 kev (σ=82) type 2: <E c >=135 kev (σ=103)

21 BROAD BAND SPECTRA OF THE COMPLETE SAMPLE not easy to constrain: complexity, modelling (many upper limits) Measured E c clusters around 100 kev Bulk of lower limit below 300 kev NuSTAR starting to confirm INTEGRAL results source INTEGRAL NuSTAR IC 4329A 152±40 (Molina et al. 2009) 145±9 (Matt 2013 ) MCG ±18 (Beckmann et al. 2008) ~100 (Matt 2013) Swift J ±33 (Panessa et al. 2011) ~ (Marinucci ) ( Brindisi workshop)

22 BROAD BAND SPECTRA OF THE COMPLETE SAMPLE Although Γ, R and E C are strongly linked in the fitting procedure, NO evidence for correlations between them has been found

23 HOST GALAXIES OF INTEGRAL AGN OBSCURATION ON LARGE SCALE 1) The effect of bars in AGN: X-ray absorption and bar strength Non axisymmetric internal perturbations such as bars are often suspected to be a way to channel gas from the outer part of a galaxy to its central regions. The resulting concentrations of gas can play a role in the obscuration and might be relevant for AGN unification theory previous studies: Maiolino NGC et 1365 al. 99 STRONG CORRELATION in Sey 2 between N H and presence of bar in the host galaxy 80% of CT are in strongly barred (SB) galaxies Results confirmed in 2007 by Maiolino & Risaliti

24 The effect of bars in the INTEGRAL AGN sample 143 source out of 272 for which bar info are available 20% of the sample Morphological classification taken from Hyperleda catalogue NO CORRELATION BETWEEN ABSORPTION AND PRESENCE OF BAR ALSO IN TYPE 2 ONLY BUT NEED TO TAKE INTO ACCOUNT BIAS DUE TO LACK OF CT AT HIGH z work in progress

25 b) Inclination of host galaxy (axial ratio b/a) can have a role in the X-ray absorption SWIFT J ESO 323-G77 b/a = 0.2 Edge-on b/a = 0.92 Face-on

26 axial ratio (previous studies) Simcoe+ 97 All have a deficit of edge-on Sy 1 but looks like these are recovered going to higher energies. Schmitt+ 01 IR

27 axial ratios in the INTEGRAL sample type 2 type S type 1 1 E a) if absorber/torus aligned with galaxy: Sy1 face-on and Sy2 edge-on b) if not, no correlation between Sy type and axial ratio expected type 2 neither works : type 1 S E Sy 2 uncorrelated with a/b Sy 1 correlated with a/b need for dual absorbers (proposed by Maiolino & Rieke 95)

28 where is this extra absorption? NA Is it related with N H measured in X-rays? GA Gelbord et al. 05 Heavily obscured N H > over all b/a NA i.e. torus (no alignment) Unabsorbed mainly in face-on galaxies neither NA or GA Mildly obscured N H ~10 22 difficult to associate to a given absorber optical data needed work in progress

29 Future Prospects multi-waveband studies of INTEGRAL AGN Radio: see talks by Molina and Panessa Very high energy (GeV /TeV): see Bassani talk Optical/X and hard-x: absorption on large scale systems in interaction (merger /dual objects) Study AGN activation Probe relation with absorption Understand how black holes grow

30 X-RAY ABSORPTION AND GALAXY INTERACTION NI 62% I 38% I NI 0 type 1 type 2 interaction is not relevant for the X-ray absorption