The mass-energy budget of the
ionised outflow in NGC 7469
Alexander J. Blustin
STFC Postdoctoral Fellow, UCL Mullard Space Science Laboratory
In collaboration with G. Kriss (STSCI), T. Holczer (Technion), E. Behar (Technion),
J. Kaastra (SRON), M. Page (UCL-MSSL), S. Kaspi (Tel-Aviv), G. BranduardiRaymont (UCL-MSSL), K. Steenbrugge (Oxford)
Chandra X-ray Gratings Meeting, Cambridge, MA, 11th July 2007
What is the total mass-energy output
through an AGN wind?
X-ray absorption – more ionised
How biased is this by the waveband
in which we do the spectroscopy?
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)
Blustin et al. 2007, A&A 466, 107
Dataset and spectral continuum
• NGC 7469 (z = 0.0164) is an X-ray
and UV bright Seyfert with a lowcolumn 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
(G = 1.81) plus soft excess (we
used a 0.144 keV blackbody
component). Significant soft X-ray
residuals are visible
The X-ray absorption and emission features
Blustin et al. 2007, A&A 466, 107
Significance of narrow
spectral features
Dc2 = 16 implies 4s significance
Fitting individual ionic columns
Blustin et al. 2007, A&A 466, 107
Ion-by-ion (slab in SPEX)
absorber model superimposed
on RGS data
Individual ion columns
The AMD expresses the total line-ofsight column density as an integral
over its distribution in log x
NHtotal = (3.3 ± 0.8) x 1021 cm-2
Two main ionisation regimes:
most gas at higher levels of
ionisation
See talk by Tomer Holczer for more
details on AMDs
Blustin et al. 2007, A&A 466, 107
Absorption Measure Distribution (AMD)
Photoionised absorber modelling
Blustin et al. 2007, A&A 466, 107
Scott et al. 2005 SED for
Chandra/FUSE data
Blustin et al. 2007 SED
for XMM-Newton data
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
Photoionised absorber modelling
3 absorber
components:
X-ray 1
Log x = 0.8+0.4-0.3
Log NH = 19.5 ± 0.2 cm-2
v = -2300 ± 200 km s-1
X-ray 2
Log x = 2.73 ± 0.03
Log NH = 21.30+0.04-0.05 cm-2
v = -720 ± 50 km s-1
X-ray 3
Log x = 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
UV properties from
Scott et al. 2005
Comparison with UV-absorbing outflow
Log x
Ionic columns (1014 cm-2)
v (km/s)
NCIV
NNV
NHI
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+0.08-0.07
580+80-50
n/a
n/a
n/a
UV properties from
Scott et al. 2005
Comparison with UV-absorbing outflow
Log x
Ionic columns (1014 cm-2)
v (km/s)
NCIV
NNV
NHI
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
Identify UV component 2 with X-ray component 1
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+0.08-0.07
580+80-50
n/a
n/a
n/a
The location of the soft X-ray/UV absorbing outflow
Distance
estimates:
Rmin from
escape
velocity
Rmax from
DR/R ≤ 1
Outflow component
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 W
x
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 ~
Volume filling factor, Cv ~
1.23 mproton Lion Cv v W
x
(Labs + Lscatt) x
1.23 mproton c Lion v2 W
Kinetic luminosity, LKEout
1 .
Mout v2
=
2
Blustin et al. 2005, A&A 431, 111
The mass-energy output of NGC 7469
Mass
outflow rate
Log Kinetic
Luminosity
(Solar masses
per year)
(erg s-1)
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
The mass-energy output of NGC 7469
The
same
gas
Mass
outflow rate
Log Kinetic
Luminosity
(Solar masses
per year)
(erg s-1)
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
The mass-energy output of NGC 7469
The
same
gas
Mass
outflow rate
Log Kinetic
Luminosity
(Solar masses
per year)
(erg s-1)
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
Using the X-ray phase properties for X1/UV2
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