A Full Characterisation of the Supermassive Black Hole in IRAS
  09149-6206
  We present new broadband X-ray observations of the type-I Seyfert galaxy IRAS
09149-6206, taken in 2018 with $XMM$-$Newton$, $NuSTAR$ and $Swift$. The source
is highly complex, showing a classic 'warm' X-ray absorber, additional
absorption from highly ionised iron, strong relativistic reflection from the
innermost accretion disc and further reprocessing by more distant material. By
combining X-ray timing and spectroscopy, we have been able to fully
characterise the supermassive black hole in this system, constraining both its
mass and - for the first time - its spin. The mass is primarily determined by
X-ray timing constraints on the break frequency seen in the power spectrum, and
is found to be $\log[M_{\rm{BH}}/M_{\odot}] = 8.0 \pm 0.6$ (1$\sigma$
uncertainties). This is in good agreement with previous estimates based on the
H$\alpha$ and H$\beta$ line widths, and implies that IRAS 09149-6206 is
radiating at close to (but still below) its Eddington luminosity. The spin is
constrained via detailed modelling of the relativistic reflection, and is found
to be $a^* = 0.94^{+0.02}_{-0.07}$ (90% confidence), adding IRAS 09149-6206 to
the growing list of radio-quiet AGN that host rapidly rotating black holes. The
outflow velocities of the various absorption components are all relatively
modest ($v_{\rm{out}} \lesssim 0.03c$), implying these are unlikely to drive
significant galaxy-scale AGN feedback.
