The mass-energy budget of the ionised outflow in NGC 7469

Alexander J. Blustin

STFC Postdoctoral Fellow, UCL Mullard Space Science Laboratory

Chandra X-ray Gratings Meeting, Cambridge, MA, 11th July 2007

In collaboration with G. Kriss (STSCI), T. Holczer (Technion), E. Behar (Technion), J. Kaastra (SRON), M. Page (UCL-MSSL), S. Kaspi (Tel-Aviv), G. Branduardi-Raymont (UCL-MSSL), K. Steenbrugge (Oxford)

ionised wind

X-ray absorption – more ionised

Blustin et al. 2007, 466, 107

UV absorption – less ionised

Kriss, Blustin

et al. 2003, A&A 403, 473

Artist’s impression of ionised wind in nuclear region of a galaxy (A. Blustin)

What is the total mass-energy output through an AGN wind?

How biased is this by the waveband in which we do the spectroscopy?

Dataset and spectral continuum

• NGC 7469 (z = 0.0164) is an X-ray and UV bright Seyfert with a low-column warm absorber

• 164 ks with XMM-Newton, obtained in Nov/Dec 2004

• Highest signal-to-noise X-ray grating and CCD spectra yet obtained for this source

Basic form of spectral continuum obtained from EPIC-pn: power-law ( = 1.81) plus soft excess (we used a 0.144 keV blackbody component). Significant soft X-ray residuals are visible

Blustin et al. 2007, A&A 466, 107

The X-ray absorption and emission features

Significance of narrow spectral features

2 = 16 implies 4significance

Blustin et al. 2007, A&A 466, 107

Fitting individual ionic columns

Ion-by-ion (slab in SPEX) absorber model superimposed on RGS data

Individual ion columns

Blustin et al. 2007, A&A 466, 107

Absorption Measure Distribution (AMD)

See talk by Tomer Holczer for more details on AMDs

The AMD expresses the total line-of-sight column density as an integral over its distribution in log

NHtotal = (3.3 ± 0.8) x 1021 cm-2

Two main ionisation regimes: most gas at higher levels of ionisation

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Photoionised absorber modelling

Spectral Energy Distribution (SED) used to calculate SPEX xabs photoionised absorber model has PN spectral slope, and is normalised using fluxes from RGS and OM

Scott et al. 2005 SED for Chandra/FUSE data

Blustin et al. 2007 SED for XMM-Newton data

Blustin et al. 2007, A&A 466, 107

Photoionised absorber modelling 3 absorber components:

X-ray 1

X-ray 2

X-ray 3

Log = 0.8+0.4-0.3

Log NH = 19.5 ± 0.2 cm-2

v = -2300 ± 200 km s-1

Log = 2.73 ± 0.03Log NH = 21.30+0.04

-0.05 cm-2

v = -720 ± 50 km s-1

Log = 3.56+0.08-0.07

Log NH = 21.5 ± 0.1 cm-2

v = -580+80-50 km s-1

Blustin et al. 2007, A&A 466, 107

Velocity components in the X-ray absorber

Comparison with UV-absorbing outflow

Log v (km/s) NCIV NNV NHI

Ionic columns (1014 cm-2)

UV 1 1.61 562 ± 6 0.98 ± 0.09 2.9 ± 0.8 7 ± 2

UV2 0.51 1901 ± 6 2.0 ± 0.1 2.5 ± 0.2 2.4 ±0.5

X-ray 1 0.8+0.4-0.3 2300 ± 200 1.6 3.4 6.2

X-ray 2 2.73 ± 0.03 720 ± 50 n/a 0.00091 n/a

X-ray 3 3.56+0.08-0.07580+80

-50 n/a n/a n/a

UV properties from Scott et al. 2005

Comparison with UV-absorbing outflow

Log v (km/s) NCIV NNV NHI

Ionic columns (1014 cm-2)

Identify UV component 2 with X-ray component 1

UV 1 1.61 562 ± 6 0.98 ± 0.09 2.9 ± 0.8 7 ± 2

UV2 0.51 1901 ± 6 2.0 ± 0.1 2.5 ± 0.2 2.4 ±0.5

X-ray 1 0.8+0.4-0.3 2300 ± 200 1.6 3.4 6.2

X-ray 2 2.73 ± 0.03 720 ± 50 n/a 0.00091 n/a

X-ray 3 3.56+0.08-0.07580+80

-50 n/a n/a n/a

UV properties from Scott et al. 2005

The location of the soft X-ray/UV absorbing outflow

Outflow component

Distance estimates:

Rmin from escape velocity

Rmax from R/R ≤ 1

Blustin et al. 2007, A&A 466, 107

Calculating the mass and energy transport of the outflow

Mass outflow rate, Mout ~1.23 mproton Lion Cv v

.

Volume filling factor of the outflow obtained from the assumption that, for a radiatively driven wind:

Momentum of outflowing

matter~

Momentum of radiation absorbed and

scattered by wind

Blustin et al. 2005, A&A 431, 111

Calculating the mass and energy transport of the outflow

Mass outflow rate, Mout ~1.23 mproton Lion Cv v

.

Kinetic luminosity, LKEout = Mout v2.1

2

Volume filling factor, Cv ~ 1.23 mproton c Lion v2

(Labs + Lscatt)

Blustin et al. 2005, A&A 431, 111

The mass-energy output of NGC 7469

X-ray component 1 0.002 39.6

X-ray component 2 0.03 39.7

X-ray component 3 0.02 39.4

UV component 1 0.006 38.7

UV component 2 0.0004 38.7

Mass outflow rate(Solar masses

per year)

Log Kinetic Luminosity

(erg s-1)

The mass-energy output of NGC 7469

X-ray component 1 0.002 39.6

X-ray component 2 0.03 39.7

X-ray component 3 0.02 39.4

UV component 1 0.006 38.7

UV component 2 0.0004 38.7

Mass outflow rate(Solar masses

per year)

Log Kinetic Luminosity

(erg s-1)

The same gas

The mass-energy output of NGC 7469

X-ray component 1 0.002 39.6

X-ray component 2 0.03 39.7

X-ray component 3 0.02 39.4

UV component 1 0.006 38.7

UV component 2 0.0004 38.7

Total 0.06 40.1

Mass outflow rate(Solar masses

per year)

Log Kinetic Luminosity

(erg s-1)

Using the X-ray phase properties for X1/UV2

The same gas

Conclusions

• We estimate that ~90% of the mass outflow rate and ~95% of the kinetic luminosity are associated with the soft X-ray absorbing components in this object.

• For a complete picture, we would also want to look at the highest-ionisation gas absorbing above 6 keV.

• Is this also the case for distant X-ray faint AGN (e.g. BALQSOs) for which we can only do optical spectroscopy? This has implications for attempts to infer the mass-energy output of cosmologically-interesting AGN winds from their rest-frame UV spectra.

For further details see Blustin et al. 2007, A&A 466, 107