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)