The ionization structure of the wind in NGC 5548

1. The ionization structure of the wind in NGC 5548 Katrien Steenbrugge Harvard-Smithsonian Center for Astrophysics In collaboration with Jelle Kaastra N. Arav, M. Crenshaw, S. Kraemer, R. Edelson, C. de Vries, I. George, D. Liedahl, R. van der Meer, F. Paerels, J. Turner, T. Yaqoob

2. NGC 5548 • Well studied nearby Seyfert 1 galaxy • Low Galactic absorption • X-ray bright • Has a rather strong warm absorber • Collision 0.6-1.0 Gyr ago(Tyson et al.1998, ApJ, 116, 102) • Study the core

3. Seyfert galaxies NGC 5548, Kaastra et al. 2002 • Low luminosity AGN • Broadened emission lines in optical and UV spectra • Seyfert 1: broad and narrow lines X-ray: Absorption spectrum • Seyfert 2: broad lines in polarized light X-ray: Emission line spectrum NGC 1068, Kinkhabwala 2002

4. Geometry of the absorber Narrow and broad emission/absorption lines Viewing angle and unification Seyfert 2: edge on Seyfert 1: face on Urry & Padovani, 1995, PASP, 107, 803

5. Geometry of the absorber Elvis, 2000, ApJ, 545, 63 No absorption BAL NAL

6. Similarities between models Elvis, 2000, ApJ, 545, 63 Clouds in pressure equilibrium with a hot outflow

7. Differences between models • Difference in viewing angle • Difference in opening angle of the outflow • Difference in location of the absorber • Explains Seyfert 1 galaxies without absorption • Explains broad absorption line quasars • Expect only 1 outflow velocity • Explains IR emission • Explains Seyfert 2 galaxies

8. Open questions • Are the absorbers seen in the UV and the X-rays the same (Mathur, Wilkes & Elvis, 1995, ApJ, 452, 230) • Ionization structure of the absorber • Location and geometry of the absorber • Mass loss through wind, enrichment IGM

9. Ionization parameter • ξ = L/nr2 • L luminosity • n gas density • r distance from source

10. Observational campaign SimultaneousUV and X-ray observations:

11. UV spectra • Broad emission lines FWHM~8000 km/s • Narrow emission lines FWHM~1000 km/s • Absorption lines FWHM~100 km/s • 5 ≠ outflow v • Lowly ionized absorber Arav et al. 2001, 2003, Crenshaw et al. 2003, Brotherton et al. 2002

12. Absorption components

13. UV spectra: dusty absorber • Fit 1 ionization parameter per velocity component • In order that all 4 lines fit: play around with abundances • Abundance ratios could be explained if some C, Mg, Si and Fe are stored in dust But multiple ionization parameters per velocity component !

14. UV spectra: results Crenshaw et al. 2003: • Dusty absorber • log NOVI=20.26 m-2 logNOVIII=20.20 m-2 Arav et al. 2002,2003: • FUSE:log NOVI=19.69 m-2 • Non-black saturation • Lower limit to column density

15. X-ray spectra • Combine HETGS resolution with λ range LETGS • Probe low to highly ionized absorber

16. Are the absorbers seen in the UV and the X-rays the same ?

17. Velocity structure • Resolve the highest UV outflow v for 6 ions • Same outflow velocity structure as the UV

18. Ionization parameter • DetectO VIand lower ionized ions • log NO VI=20.6 m-2 • Inferred NH ≈ 1024 m-2 Order of magnitude more than detected in UV

19. Comparison • Same velocity structure, same ionization • Different column densities Possible solution(Arav et al. 2002): The absorber does not cover the NEL’s → Non-black saturation, underestimate NH Velocity dependent covering factor in the UV UV and X-ray absorber are the same

20. Velocity structure • If we measure 1 outflow v • Higher ionized ions have higher outflow velocities

21. Ionization structure of velocity components HST STIS FUSE

22. Ionization structure of the absorber Both models require clouds in pressure equilibrium. Pressure equilibrium implies several separate components with a different ionization parameter.

23. Ionization structure • Iron is best indicator of ionization • H abundance = 10 • Lower ionized iron ionization is uncertain (Netzer et al. 2003)

24. Ionization structure • RGS data • Fe only • Model with 3,4 and 5 ionization components

25. Pressure equilibrium Ξ = L/ (4πcr2P) = 0.961x104ξ/T L luminosity, r distance c speed of light P ideal gas pressure P = nkT T temperature In Ξ versus T plot means vertical section constant nT

26. Ionization structure Are the different ionization states in pressure equilibrium?

27. Continuous ionization distribution • Assume solar abundances • Continuous distribution over 3.5 orders in ξ • dNH/dlnξ~ξα • α=0.40±0.05

28. Spectral variability: low state • New observation • March 15 2005 • Low hard state • Preliminary results • M. Feňovčík

29. Spectral variability: low state • Stronger OV, O III • Noisy O IV • Column density of O VI, O VII and O VIII did not vary • Supports continuum ionization model • Hard to explain in clouds in pressure equilibrium model Marian Feňovčík, in prep.

30. Spectral variability: NGC 3783 RGS EPIC pn Higher ξ absorber is variable, while low ξ is not in NGC 3783 XMM data (Behar et al. 2003, Reeves et al. 2004)

31. Geometry of the absorber

32. Geometry of the wind

33. Geometry of the absorber • Narrow streams • Dense core lowly ionized • One stream per outflow velocity component observed • Gives asymmetric line profile Arav et al., 1999, ApJ, 516, 27

34. Can mass escape? • Important for the enrichment of the IGM and AGN feedback • vesc = (2GMBH/r)1/2 • MBH = 6.8 · 107 Mo (Wandel 2002) • v ≥ 166 km/s to 1041 km/s • r ≥ (5.8/vr2) · 105 pc • Assuming vr = 1000 km/s →r ≥ 0.6 pc • Assuming all mass escapes and mass loss = mass accretion: Mloss = 0.3 M0/yr

35. Conclusions • The UV and X-ray absorbers are the same • The absorbers are not in pressure equilibrium • The ionization structure is likely continuous spanning 3.5 orders in ξ • The outflow occurs in narrow steamers • Likely, part of the outflow escapes