the powerful black hole wind in the luminous quasar pds 456 james reeves astrophysics group, keele...
TRANSCRIPT
The Powerful Black Hole Wind in the Luminous Quasar PDS
456James Reeves
Astrophysics Group, Keele University & UMBC
in collaboration with: E. Nardini (Keele), J. Gofford (Keele/UMBC) - M. Costa, G. Matzeu (Keele) - V. Braito (Brera/ASI) - F. Harrison, D Walton (Caltech) - G. Risaliti (Arcetri/CfA), P.T. O’Brien (Leicester), E. Behar (Technion), G. Matt (Roma) T.J. Turner
(UMBC), M. Ward (Durham) and NuSTAR team
NuSTAR Special Session, High Energy Astrophysics Division Meeting, Chicago, August 17-21, 2014
Black hole/host galaxy coevolution
Kormendy & Ho 2013
Jahnke & Macciò 2011
AGN feedback is widely accepted as the underlying mechanism but… Hierarchical assembly through galaxy mergers might be equally
relevant
King 2010
Tombesi+ 2010
Maiolino+ 2012
Powerful disc winds are naturally
expected at high accretion rates:
How powerful are disc winds actually?
The geometrical structure has to be assumed rather than directly
measured: it is therefore still unclear whether disc winds have sufficient mechanical energy to power feedback on galactic
scales
The mass-loss rate depends on the physical, dynamical and geometrical properties of the wind. The detection of narrow, blueshifted X-ray
absorption lines does not provide on its own any solid constraint on its total
energetics.
★ Solid angle: frequency of disc wind signatures among local AGN
★ Column density: modelling of absorption by photo-ionised gas
★ Outflow velocity: observed line’s energy following identification
★ Launch radius: ionisation state of the gas and escape velocity
The possible Rosetta Stone: PDS 456
The new campaign: 5 simultaneous XMM + NuSTAR observations
Rest-frame energy (keV)
Ra
tio
PDS 456 is the most luminous radio-quiet AGN in the local Universe (z < 0.3)
Reeves+ 2003
Background: systematic detection of a deep
trough above 7 keV rest-frame, occasionally
resolved into a pair of individual absorption
lines: evidence for a large column density of
highly ionised matter outflowing gas at about one third of the speed of light.
PDS 456 is the ideal target for studying AGN winds in the Eddington-limited
regime.
The importance of a broadband view
A persistent wide-angle wind
The line apparently responds to continuum
changes over ~7-10 days (see also Gofford+ 2014)
The P-Cygni-like profile is resolved independently
at any epoch (aperture > 50º from FWHM)
Some (interesting) numbers
All the critical information can now be determined from the data: 1. absorbed versus re-emitted luminosity 2. self-consistent photo-
ionisation modelling 3. line energy and width 4. variability timescale
A few per cent of the Eddington limit is already enough to prompt
significant feedback on the host galaxy (e.g. Hopkins & Elvis 2010)
For a wind lifetime of 107 yr the energy released through the accretion disc wind likely exceeds the binding energy of the
bulge:
Summary★PDS 456 is an exceptionally luminous AGN in the local Universe, yet representative of an accreting SMBH during its quasar phase and thus
offering a unique view of the possible mechanism that links the growth
of the central black holes to the evolution of their host galaxies over
cosmic time.★The new campaign XMM + NuSTAR campaign allowed the first direct
measure of the mass-loss rate and total energetics of a disc outflow,
whose mechanical power is largely consistent with the requirements of
feedback models.★At the peak of the quasar epoch, such powerful winds would have provided the energy and momentum to self-regulate the SMBH growth
and control the star formation in stellar bulges.★The present-day scaling relations are left as a record of this process.
Nardini+ (submitted)