Properties of the NLR from Spatially Resolved Spectroscopy

1. Properties of the NLR from Spatially Resolved Spectroscopy Nicola Bennert University of California Riverside Collaborators: Bruno Jungwiert, Stefanie Komossa, Martin Haas, Rolf Chini

2. Extended enough to be directly accessible Affected by ionizing source, presence of torus, jets, … Forbidden lines for diagnostics The Narrow-Line Region of Active Galaxies [OIII] narrow-band imaging commonly used (e.g. Mulchaey et al. 1996, Schmitt et al. 2003)

3. NLR size-luminosity relation Schmitt et al. 2003 Bennert et al. 2002 constant product U x n Strömgren: constant density? AGNs: same U, n, ionizing SED? (Netzer 1990) ⇒ionization mechanism, AGN lifetimes (Martini et al. 2004), BH mass? ⇒Disappearing NLR (Netzer et al. 2004)?

4. Extended enough to be directly accessible Affected by ionizing source, presence of torus, jets, … Forbidden lines for diagnostics [OIII] narrow-band imaging commonly used (e.g. Mulchaey et al. 1996, Schmitt et al. 2003) But: dependency on sensitivity Mulchaey et al. 1996 vs. Schmitt et al. 2003: 6 times larger NLRs! And: emission contaminated by contributions from e.g. star formation/shock-ionized gas The Narrow-Line Region of Active Galaxies

5. Probe AGN photoionization, measure „true“ NLR size (diagnostic diagrams) Probe physical parameters (U, n , E_(B-V), T, v, surface brightness) VLT & NTT observations of 6 Sy1s, 6 Sy2s (Bennert et al. 2006a,b,c) Answers from Spectroscopy Detailed case study: Seyfert-2 galaxy NGC 1386 (Bennert et al. 2006a) Bennert et al. 2006 Bennert et al. 2006 Correction of stellar contribution: galaxy itself at 18‘‘ distance Reddening correction (dust)

6. Spatially resolved diagnostics Separation NLR/HII region (2Sy1s, 2Sy2s), confirmed by CLOUDY modeling ⇒ NLR size free of stellar contamination: r ~ 6‘‘ (here) vs. r ~ 3‘‘ (Schmitt et al. 2003) vs. r ~ 12‘‘ (Fraquelli et al. 2003)

7. Electron density and ionization parameter Both radially decreasing (1/r) ⇒ excitation of the NLR due to photoionization ⇒ No Strömgren behaviour

8. Stellar and gaseous kinematics curves similar, signs of rotational motion, no difference in HII region ⇒NLR gas distributed in a disk rather than a sphere ⇒ torus axis not aligned with galaxy axis, ionization cone lies in disk? Central AGN and galaxy randomly orientated? (e.g. Kinney et al. 2000)

9. The Narrow-Line Region of Active Galaxies NLR size free of stellar contamination NLR gas in a disk Torus axis in galaxy disk? Unified model supported NLR photoionized

11. BLR size from literature („reverberation mapping“; Kaspi et al. 2000) NLR size versus BLR size Bennert et al. 2004 ⇒ determine BH masses MBH = (105.22 M⊙) v30002RNLR,10.88MBH = (108.83 M⊙) v30002L44,[OIII]0.48

12. Unified model (Antonucci 1993) & „receding“ torus (Lawrence 1991) Modeling: NLR size and luminosity ⇒ Different slopes for type 1/2 flatter than

13. Reddening determined from Hα/Hβ continuum slope ⇒ locally varying amount of dust intrinsic to the NLR? (true for all objects)

14. Seyfert 2s Reddening of nuclear spectrum higher Seyfert 1s [OIII] 4363, [FeVII], [FeX] higher Ionization parameter higher, decreases faster Higher temperatures Comparison of type-1 and type-2 Electron densities comparable (decrease faster in Sy1s) In agreement with statistics: high-ionization lines & high-critical-density lines stronger in Sy1s ⇒ Highly-ionized gas clouds are located close to nucleus and can be hidden by torus (e.g. Nagao et al. 2000)

15. CLOUDY modeling ⇒ transition in first and third diagnostic diagram: decreasing ionization parameter & metallicity But not for second diagnostic diagram Solid line 1: ionization parameter (log U = -4.0 … -1.5 steps of 0.5, from bottom to top; n = 800, 400, 200 cm-3; r = 50, 100, 250 pc, from right to left) Dotted lines 2&3: metal abundances (Z = 3…0.05 solar, from right to left; log U = -2.8 for line 2; log U = -3.7 for line 3) Dash-dotted lines 4&5: N & S abundances (Z, U dito 2&3) Dashed line 6: high density (n = 1000000 cm-3; U dito 1)