Micro-Turbulence in Emission and Absorption in AGN. Steve Kraemer (Catholic Univ. of America). Via collaborations with: Mike Crenshaw (GSU), Mark Bottorff (Southwestern), Jane Turner (UMBC), Lance Miller (Oxford). Is Micro-Turbulence Present?.
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Micro-Turbulence in Emission and Absorption in AGN
Steve Kraemer (Catholic Univ. of America)
Via collaborations with:
Mike Crenshaw (GSU), Mark Bottorff (Southwestern), Jane Turner (UMBC), Lance Miller (Oxford)
Why not in AGN?
convective acceleration: time independent acceleration of fluid w.r.t space
non-linear advection operator → distortion of velocity field
Q = ηνρ (vturb 3 /D) ergs cm-3 s-1
(vturb equivalent to b or 1/1.665 FWHM)
NV 1240, affected by photo-excitation + heating, [NeV] 3426 bossted by heating.
High resolution X-ray spectra of AGN show myriad of soft X-ray emission lines arising in NLR
Ratios of resonance to forbidden lines in He-like triplets can indicate temperature and density. High r/f ratios: collisionally excited gas (Ogle et al. 2000); Photo-excitation (Sako et al. 2000; Kinkhabwala et al. 2002)/
Narrowness of Radiative Recombination Continua suggests low Temps (Photo-ionization) → photo-excitation.
But photo-excitation depends strongly on vturb
Sim of OVII triplet, courtesy of R. Porter.
Cloudy models, (logU=0), showing dependence of r/f ratio on vturb and column density.
Is turbulence present in intrinsic absorbers?
Most readily answered using high-res UV spectra of Type 1 Seyferts.
STIS spectra of NGC 5548, showing multiple kinematic components in HI, NV, and CIV. Note the difference in the profiles.
STIS spectra of NGC 3783 (Gabel et al. 2003), showing variations in absorption over three epochs, separated by 13 and 9 months. Radial velocity changes or profile changes (superposition of components)?
Comparison of FWHM and total H column densities (derived from photo-ionization models) for absorbers in NGC 3516, NGC 4051, NGC 4151, NGC 5548, and Mrk 509 (Crenshaw, in prep). Note even smallest large column density absorbers have super-thermal widths.
Slope of Nh to FWHM is ~ 1.5. For Kolmogorov cascade, slope is unity. Note: slope is flatter for the lower envelope. Combination of turbulence and superposition?
If minimum widths due to turbulence, what would we see?
Two cases, logU=-1.5, logNh=20.5
FWHM = 1000 km/s at face; no decay. Profile difference dominated by differences in ionic columns and oscillator strengths.
FWHM = 1000 km/s at face; exponential decay. Local value of vturb has strong effect.
Conclusions? Perhaps“open questions” is better term: