The mass-energy budget of the ionised outflow in NGC 7469 Alexander J. Blustin STFC Postdoctoral Fellow, UCL Mullard Space Science Laborator Chandra X-ray Gratings Meeting, Cambridge, MA, 11 th 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)
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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.
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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
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