Using XMM-Newton observations , we investigate the scaling and structural properties of the ICM entropy in a sample of 10 nearby ( z < 0.2 ) relaxed galaxy clusters in the temperature range 2-9 keV .
We derive the local entropy-temperature ( S – T ) relation at R = 0.1 , 0.2 , 0.3 and 0.5 R _ { 200 } .
The logarithmic slope of the relation is the same within the 1 \sigma error at all scaled radii .
However , the intrinsic dispersion about the best fitting relation is significantly higher at 0.1 R _ { 200 } .
The slope is 0.64 \pm 0.11 at 0.3 R _ { 200 } , in excellent agreement with previous work .
We also investigate the entropy-mass relation at density contrasts \delta = 5000 , 2500 and 1000 .
We find a shallower slope than that expected in simple self-similar models , which is in agreement with the observed empirically-determined entropy-temperature and mass-temperature scaling .
The dispersion is smaller than for the S – T relation .
Once scaled appropriately , the entropy profiles appear similar beyond \sim 0.1 R _ { 200 } , with an intrinsic dispersion of \sim 15 per cent and a shape consistent with gravitational heating ( S ( r ) \lower 3.0 pt \hbox { $ \buildrel \textstyle \propto \over { \textstyle \sim } $ } r ^ % { 1.1 } ) .
However , the scatter in scaled entropy profiles increases with smaller scaled radius , to more than 60 per cent at R \lesssim 0.05 R _ { 200 } .
Our results are in qualitative agreement with models which boost entropy production at the accretion shock .
However , localised entropy modification may be needed to explain the dispersion in the inner regions .