Context : Fairall 51 is a polar-scattered Seyfert 1 galaxy , a type of active galaxies believed to represent a bridge between unobscured type-1 and obscured type-2 objects .
Fairall 51 has shown complex and variable X-ray absorption but only little is known about its origin .

Aims : In our research , we observed Fairall 51 with the X-ray satellite Suzaku in order to constrain a characteristic time-scale of its variability .

Methods : We performed timing and spectral analysis of four observations separated by 1.5 , 2 and 5.5 day intervals .

Results : We found that the 0.5–50 keV broadband X-ray spectra are dominated by a primary power-law emission ( with the photon index \approx 2 ) .
This emission is affected by at least three absorbers with different ionisations ( \log \xi \approx 1 – 4 ) .
The spectrum is further shaped by a reprocessed emission , possibly coming from two regions – the accretion disc and a more distant scattering region .
The accretion disc emission is smeared by the relativistic effects , from which we measured the spin of the black hole as a \approx 0.8 \pm 0.2 .
We found that most of the spectral variability can be attributed to the least ionised absorber whose column density changed by a factor of two between the first ( highest-flux ) and the last ( lowest-flux ) observation .

Conclusions : A week-long scale of the variability indicates that the absorber is located at the distance \approx 0.05 pc from the centre , i.e. , in the Broad Line Region .