The Spectral Energy Distributions of Narrow-line Seyfert 1 Galaxies

1. The Spectral Energy Distributions of Narrow-line Seyfert 1 Galaxies Karen M. Leighly The University of Oklahoma

2. Summary • The spectral energy distribution, as either the origin or the consequence, is key for understanding Narrow-line Seyfert 1 galaxies.

3. ASCA Observations of NLS1s Leighly 1999 Emission region size ~black hole mass Absolute accretion rate

4. Variance / Soft Excess Correlation Leighly 1999 1H 0707-495 Ton S180 Alphaxx is a measure of the strength of the soft excess

5. z=0.04 XMM-Newton observation 10/2000 Exposure ~ 40 ks Boller et al. 2002 Z=0.06 XMM-Newton observation 12/2000 Exposure ~30 ks Vaughan et al. 2002 1H 0707-495 Ton S180 Andrea Crews, Carnegie Mellon Chiho Matsumoto, OU

6. Prominent soft excess. Well modeled by a single blackbody Subtle soft excess Modeled as two Comptonized spectra by Vaughan et al. Spectral Properties

7. High variance Variance roughly independent of energy. Low variance Variance roughly independent of energy. Light Curves

8. 2-10 keV structure function appears harder than other bands on short time scales. 3-10 keV structure function appears similar to other bands on short time scales. Structure Function Analysis

9. Hard X-rays mirror soft X-rays loosely. Hard X-rays show additional short time scale variability Implication: two physically distinct components Hard X-rays and soft X-rays show nearly identical variability. Implication: components are not distinct. Perhaps a distribution of optical depths and temperatures. Energy-sliced Light Curves

10. Hard X-rays much more variable than soft X-rays. Qualitatively similar to behavior during XMM-Newton observation. Also true in I Zw 1, in which a hard flare was observed? (See poster by Luigi Gallo) Chandra Observation of 1H 0707-495

11. Optical Spectra • No profound differences between the optical spectra, as expected. John Moore, OU

12. Strong low-ionization lines High SiIII]/CIII] ratio Strongly blueshifted, low equivalent width CIV line. Strong high-ionization lines Moderate SiIII]/CIII] ratio Weakly blueshifted, high equivalent width CIV. UV Spectra

13. CIV in a Sample of NLS1s Ton S180 1H 0707-495 Symmetric line Blueshifted line

14. An Interpretation • CIV line in some NLS1s is dominated by emission in a wind, resulting in the blueshift (red side is blocked by optically thick accretion disk). • What determines the presence of a wind? • The answer: the spectral energy distribution. X-rays relatively strong compared with UV X-rays relatively weak compared with UV

15. Resonance Line Driven Winds • What is required for a wind? • Resonance scattering of UV photons drives the wind, so the UV should be strong. • X-rays can overionize the wind (e.g. Proga et al.), so X-rays should be weak. • So steep alphaox should be associated with a wind.

16. 1H 0707-495 and Ton S180

17. Low-Ionization Lines • Low-ionization lines (FeII, SiII) are strong in windy NLS1s. • Filtering continuum through the wind creates a much harder continuum that produces lines characterized by low ionization potential. • Many details in Leighly & Moore (ApJ, submitted) • Also, next Tuesday-RIKEN, Wednesday-ISAS

18. Why do some NLS1s have blueshifted lines? • A blue UV continuum and weak X-ray emission can accelerate a wind without overionizing it. The wind emits blueshifted high-ionization lines (CIV, NV, OVI). • The wind filters the continuum before it strikes the intermediate-line emitting region. That region emits rather low-ionization lines (FeII, MgII, SiII).

19. Why do some NLS1s not have blueshifted lines? • Strong X-ray emission ionizes the wind before it can be accelerated. • The unfiltered continuum illuminates disk atmosphere producing strong relatively narrow and symmetric high-ionization lines.

20. Extreme NLS1s: RE 1034+39 • Simultaneous ASCA, EUVE, FUSE observations • A much harder continuum than that of 1H 0707-495 Casebeer & Leighly, in prep. Darrin Casebeer, OU

21. Emission lines in RE1034+39 can all be modelled with nearly the same profile - no blueshifted emission, as predicted.

22. Semi-empirical SED modeling • Semi-empirical spectral energy distributions parameterized by cutoff temperature

23. Modeling RE1034+39 • Darrin looked for an SED consistent with the lines he measures. He concludes that he very hard spectrum is not only consistent but required to produce the observed equivalent widths and ratios

24. PHL 1811 • Simultaneous HST and Chandra observations • Intrinsically X-ray weak - no evidence for significant absorption Leighly, Halpern & Jenkins in prep.

25. Factor of 4 variability in 12 days - rules out scattered X-rays. Nominal NLS1 photon index (2.25) plus black body - rules out absorption Ratio of the two spectra reveal evidence for spectral variability Intrinsically X-ray Weak 12/17/01 12/05/01

26. No clear evidence for intrinsic absorption on CIV - small feature has equivalent width of 0.2 angstroms. PHL 1811 is very unusual compared with other soft X-ray weak AGNs No Evidence for Absorption Galactic

27. CIV line is blueshifted, as expected. NV line may be blueshifted also. PHL 1811

28. Strong UV FeII in PHL 1811 • No semiforbidden or forbidden lines.

29. Very low-ionization lines • Strong NaD and CaII H&K lines

30. Modeling done by Yair Krongold and Fabrizio Nicastro (CfA). First component: U=1.14 logNH=21.92 Vout=24,000 km/s Second component: U=1.47 logNH=22.4 Vout=45,000 km/s Also Pounds et al. X-ray Outflows in 1H 0707-495

31. Summary • The spectral energy distribution, as either the origin or the consequence, is key for understanding Narrow-line Seyfert 1 galaxies. • NLS1 emission lines are a consequence of the SED, both in their excitation and dynamics. • Origin of the SED is in the central engine. Dispersion in X-ray spectral and variability properties among NLS1s indicates different conditions, geometries, … • And so we attempt to approach a complete picture of NLS1s…