1 X-ray Diagnostics of Physical Conditions in Warm Absorbers Y. Krongold (UNAM) N. Brickhouse (CfA) M. Elvis (CfA) F. Nicastro (CfA) S. Mathur (Ohio State U.) D. Liedahl (LLNL)

2  Found in the X-ray and UV spectra of 1/2 of all Seyfert 1 galaxies  Blueshifted ( km s -1 )  winds  m OUT  m accr  dynamically important Valuable to understand quasars Interaction with ISM Metal pollution of the IGM Warm Absorbers

3 NGC 3783  Bright Seyfert galaxy redshift (2926 km s-1)  Extensively observed in the X-rays Monitored by the Chandra HETGS, Total exposure of 900 ksec > 2000 counts per resolution element at 7 A

4 NGC 3783 Chandra MEG 900 ksec exposure 1keV

5 Modeling with PHASE  Based on APED (Smith et al. 2001)  accuracy in the wavelength  Plus data for inner shell transitions (Behar et al. 2001, 2002), and from Verner list  Ionization balance from CLOUDY  Includes a Voigt Profiles  Self Consistent Model  Global Fit

6 NGC 3783 Model  Photoionization Equilibrium Models  3 Free parameters per absorption component: U =Q/4  cr 2 n Ionization Parameter N H Column Density V OUT Outflow Velocity  2 Absorption Components

7 NGC 3783 Chandra MEG 900 ksec exposure 1keV

8 NGC 3783 Chandra MEG 900 ksec exposure

9 Model Highlights  Simple solution  only 2 absorbing components (LIP and HIP)  Fits more than 100 features with only 6 free parameters.  Predicts reasonable absorption in the UV by the LIP  Netzer et al. (2003) modeled a third hotter component (Fe K-shell, VHIP)

10 Does not fit two significant LIP lines: Si X, Si XI  Lack of low temperature (n=0) DR rates for Fe M-shell (Netzer et al. 2003; Netzer 2004; Kraemer Ferland and Gabel 2004) Si X-XI

11 Other Representation  Many Charge states present in the spectrum  Continuous Radial Flow of Ionization structures Several charge states of the same element are significantly present  Not a global fit, but based on ion by ion Fits everything 40 free parameters Not self consistent

12  Pressure Equilibrium  Similar kinematical properties  Confirmed by Netzer et al. (2003), plus 3erd component  3 phase medium Phases of the same medium:  1/P

13 Another Case of Pressure Balance: NGC 985  Pressure Equilibrium  Similar kinematical properties  Marginal evidence of 3rd component  3 phase medium?  1/P Krongold et al. 2004, ApJ in press 80ksec exposure with Chandra HETGS

14 Constraining the Structure and Location of the Absorber

15 Constraining the Structure of the Absorber Continuous Flow  Several Charge States of the same element  Averaged absorption is observed  No response to flux variations by factors < 3-5 Clumped Gas  Should respond even to moderate flux variations  Isolated Components  vary as expected in PI   U   Flux  Opacity variation in response to flux variations

16 Variability on NGC 3783 (LIP) Bin size of 0.25 Å DataPhotoionization Equilibrium Model Krongold et al. 2005, ApJ in press 2X flux increase

17 The UTA varies as expected in PI Data Ratio Model Ratio Significance ~10

18 Implications of Variability  Variability observed in the UTA  rules out a Radial Continuous Flow of Ionization Stages  If LIP in PI Using t obs as upper limit to recombination time  n e  10 4 cm -3 Using n e and U1/n e D 2  D < 6 pc (Reeves et al. 2004; Nicastro et al 1999; Netzer et al. 2002; Kriss and Blustin et al. 2003, Kaastra et al.2004) ΔD <.15 pc  Compact Absorber  Behar et al. (2003) D > 2 pc

19 Further Constraints of the Density  Most Determinations are Upper or Lower Limits  We need to constrain the density n e to constrain D  Diagnostics of n:  Atomic Physics (Kaastra 2004)  Time Evolving Photoionization Models (Nicastro 1999)

20 Constraining the Line Widths of the Absorber Constraining the Geometry?

21 The width of the Lines  Absorption Lines are not Resolved  We have to constrain the width of the Lines indirectly  Through Models (Widths > 200 km s -1 )  Through UV data (Widths between km s -1 )

22 Voigt Profiles  Convolution of Natural and Doppler Broadening  Voigt Parameter a  Γ/Δ  Not relevant in other bands a << 1  Relevant in X-rays a > 1 (Inner shell Transitions)  Affects the Depth at the core of the line:  o N i f ul  o

23  o N i f ul  o Fe Inner Shell vs. Outer Shell

24 Constraining the Geometry UV data Constraints (Figure by Arav 2003) UV widths >> X-ray widthsUV widths ~ X-ray widths UV X-ray Constraining the widths we can constrain the angle of the flow Transverse Flow

25 Conclusions  WA can be modeled with a Simple picture Fits almost all absorption features with only few free parameters  3 or 2 phases  Observed in other objects (NGC 5548, Kaastra et al 2002; IRAS , Sako et al. 2001, etc.) Intrinsic property related to the structure of the nuclear environment of AGN  Pressure equilibrium (and similar kinematics) Suggests pressure confinement  Observed Variability Rules out a Radial Continuous flow  clumped gas  Better Diagnostics in n e and D  Better Diagnostics of the widths  Geometry  Consistent with transverse flow (consistent with UV observations)

26 Fe XVII-XXI does NOT vary simply (as expected in PI at constant density) Variability on NGC 3783 (HIP)

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28 Fe Inner Shell Si Complex between 6-7 A Inner Shell Transitions Outer Shell

29 Implications  Observed variability in the absorbing components is consistent with variation at constant pressure in a PI multi-phase wind  3 phase medium  Change in constant pressure  t Pgas < t PI  Fragmentation of the absorber in cloudlets (as suggested by the UV obs, Gabel et al. 2003)

30  LIP (Fe VII-XII) vary as expected in PI  HIP (Fe XVII-XXI) does not vary simply  VHIP (Fe XXIV-XXVI) vary as expected in PI (Reeves et al. 2004)  The HIP could be out of PI (Time evolving effects)  different location than that of the LIP and the VHIP  An scenario of pressure confinement can also explain the observed variation of the 3 components. Variation in Pressure Balance and PI

31 BeppoSAX BeppoSAX data of NGC 985  1/P 3X flux increase  1/P Krongold et al Variation of HIP in PI and const. n e Chandra VHIP

32 Observational limitations UV spectra have 20 times better spectral resolution Difficult component identifications Lack of simultaneous observations The UV/X-ray connection is uncertain:

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35 Fe Inner Shell

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