Abstract

We present new broad-band 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 ionized 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 characterize 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 [MBH/M⊙] = 8.0 ± 0.6 (1s uncertainties). This is in good agreement with previous estimates based on the Ha and Hβ 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 per cent confidence), adding IRAS 09149-6206 to the growing list of radio-quiet active galactic nuclei (AGNs) that host rapidly rotating black holes. The outflow velocities of the various absorption components are all relatively modest (vout ≤ 0.03c), implying these are unlikely to drive significant galaxy-scale AGN feedback.