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

Overview Introduction Open questions UV spectra and results X-ray spectra Ionization structure Geometry of the wind Mass loss through the wind Conclusions

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

Seyfert galaxies Low luminosity AGN 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

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

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

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

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

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

Photo-ionized plasma Strong radiation field Low density gas Plasma is ionized by absorbing photons Gives specific triplet ratios and series line ratios Optically thin → ignore radiative transfer Godet, Collin & Dumnont, 2004

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

XMM-Newton RGS (7-38 Ǻ) spectral resolution 0.07 Ǻ FWHM EPIC MOS EPIC pn Large effective area Simultaneous observations

Chandra HETGS (1-24 Ǻ) LETGS ( 1-180 Ǻ) Spectral resolution between 0.012 Ǻ and 0.05 Ǻ Long wavelength range Low effective area Non-simultaneous observations

Observational campaign RGS 137 ks July 2001 Simultaneous UV and X-ray observations: HETGS 170 ks Jan. 2002 LETGS 340 ks HST STIS 21 ks

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

Absorption components Outflow velocity FWHM Log NC IV Log NN V 166 km/s 61 km/s 17.76 m-2 18.16 m-2 336 km/s 145 km/s 18.43 m-2 18.86 m-2 530 km/s 159 km/s 17.97 m-2 18.94 m-2 667 km/s 43 km/s 17.75 m-2 1041 km/s 222 km/s 18.05 m-2 18.44 m-2

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 C 0.35 N 1 O 0.75 Mg 0.2 Si 0.06 Fe 0.05 But multiple ionization parameters per velocity component !

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

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

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

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

Order of magnitude more than detected in UV Ionization parameter Detect O VI and lower ionized ions log NO VI=20.6 m-2 Inferred NH ≈ 1024 m-2 Order of magnitude more than detected in UV

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

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

Ionization structure of velocity components HST STIS FUSE

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

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

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

Pressure equilibrium Ξ = L/ (4πcr2P) = 0.961x104 ξ/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

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

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

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

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.

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)

Geometry of the absorber

Geometry of the wind v (km/s) -166 -1040 ξ=1 0.0007 0.0001 ξ=1000 0.7 0.1

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

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

Broad emission lines Very weak O VII triplet Expected from optical and UV ionization

Future work Has the ionization a cut-off, or is most of the gas completely ionized? ASTROE-2 Launch: summer 2005 High resolution high energy grating Study the highly ionized universe

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