1 / 25

X-ray Diagnostics of Physical Conditions in Warm Absorbers

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). Warm Absorbers. Found in the X-ray and UV spectra of 1/2 of all Seyfert 1 galaxies

chastity-dominguez
Download Presentation

X-ray Diagnostics of Physical Conditions in Warm Absorbers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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. Warm Absorbers • Found in the X-ray and UV spectra of 1/2 of all Seyfert 1 galaxies • Blueshifted (500-1000 km s-1) winds • mOUTmaccr dynamically important Valuable to understand quasars • Interaction with ISM • Metal pollution of the IGM

  3. NGC 3783 • Bright Seyfert galaxy redshift 0.0097 (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. 1keV NGC 3783Chandra MEG900 ksec exposure

  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cr2n Ionization Parameter • NH Column Density • VOUT Outflow Velocity • 2 Absorption Components

  7. 1keV NGC 3783Chandra MEG900 ksec exposure

  8. NGC 3783Chandra MEG900 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. Si X-XI 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)

  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 80ksec exposure with Chandra HETGS Krongold et al. 2004 , ApJ in press

  14. Constraining the Structure and Location of the Absorber

  15. 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 Constraining the Structure of the Absorber • Opacity variation in response to flux variations

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

  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 tobs as upper limit to recombination time  ne  104 cm-3 • Using ne and U1/neD2 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 densityneto constrain D • Diagnostics of n: • Atomic Physics (Kaastra 2004) • Time EvolvingPhotoionization Models(Nicastro 1999)

  20. Constraining the Line Widths of the AbsorberConstraining 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 100-200 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Nifulo

  23. Fe Inner Shell vs. Outer Shell oNifulo

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

  25. Conclusions • WA can be modeled with a Simple picture • Fits almost allabsorption features with only few free parameters • 3 or 2 phases Observed in other objects(NGC 5548, Kaastra et al 2002; IRAS 13349+2438, 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 RadialContinuous flow clumped gas • Better Diagnostics in neand D • Better Diagnostics of the widths  Geometry • Consistent with transverse flow (consistent with UV observations)

More Related