AMD Absorption Measure Distribution Evidence for Thermal Instability? By Tomer Holczer Cambridge, MA July 2007

Outline Interesting Questions about AGN outflows Absorption Measure Distribution analysis – The method Results Thermal Instability?

Some Interesting Questions Where is the wind? How close is it to the engine? Are there several absorbing components or a continuous distribution? Is the absorber in pressure equilibrium? Do thermal instabilities play a role?

Fig 1 : NGC 3783 flux – absorption lines from all charge states From neutral to H-like (5 orders in  )‏ The Data

Outflow Model : Method Determine continuum Identify absorption lines; determine outflow and broadening velocity Obtain column densities from data of each individual ion by fitting all its lines Reconstruct the Absorption Measure Distribution (as a function of  )‏ Fig 2 : IRAS line profile of Fe +16 resonance at 15 Å (in black) and model in red. Fitting the broadening (width) and outflow (shift) velocity.

Absorption Measure Distribution, A New Method (analogous to emission measure distribution) Improvement on multi-component models AMD – Absorption Measure Distribution – is the gas column-density (N H ) distribution in ionization parameter ξ : AMD

Measuring N ion from HETG data Fig 3 : NGC 3783 (left panel), IRAS (middle panel), and MCG (right panel). spectra in black, model in red.

Iron ion fractional abundances NGC 3783 Fig 4: Iron ion’s relative abundances for NGC 3783 using XSTAR (Kallman & Krolik 1995)‏

Fig 5 : AMD of IRAS The lower panel is the integrated column density. For IRAS N H ~ cm -2.

Abundance Ratios Compared to Sun

Fig 6 : AMD of NGC (Blustin et al. 2007). N H ~ cm -2.

Fig 7 : AMD of NGC The cyan bins in NGC 3783 are the Krongold et al. model (with a bin width) and the green bins Netzer et al. model. N H ~ cm -2.

Photo-ionized Plasma Models for NGC 3783 red squares represent the observed gap ION (Netzer et al. 2003)‏ XSTAR (Used by Holczer et al. 2007)‏ CLOUDY (Krongold et al. 2003)‏ TITAN (Goncalves et al. 2006)‏

Cooling Curves Cooling rates at different values of ξ/T (Krolik et al. 1981))

Conclusions All outflows in the AGN’s we’ve checked are missing gas at logT ~ K We believe this is evidence for thermal instability in this region Observed unstable region is not produced exactly by codes Moreover, there are discrepancies between the different models

THE END

Fig 6 : Preliminary AMD of MCG MCG have total column density around cm -2.

2± ± ± ± ±2 MCG (A z /A Fe )/ (A z /A Fe ) O 0.7 ± ±1.41Carbon 4.3± ± ± ±0.38Nitrogen 1.9±0.42.3±0.811±91.15±0.17Silicon 1.0 ±0.36± ±0.08Sulfur 1.5 ±0.51.4±0.51.0± ±0.29Magnesium 1.9 ±0.630±201.20±0.29Sodium 1.4± ±0.83.0± ±0.44Neon 1.0± ± ± Oxygen NGC 3783 (A z /A Fe )/ (A z /A Fe ) O IRAS (A z /A Fe )/ (A z /A Fe ) O NGC 7469 (A z /A Fe )/ (A z /A Fe ) O Sun Ratios (A z /A Fe ) O from Asplund et al Element