Statistics and implications of substructure detected in a representative sample of X-ray clusters. (arXiv:1210.5130v1 [astro-ph.CO])

Statistics and implications of substructure detected in a representative sample of X-ray clusters. (arXiv:1210.5130v1 [astro-ph.CO]):
We present a morphological study of 35 X-ray luminous galaxy clusters at
0.15<z<0.3, selected in a similar manner to the Local Cluster Substructure
Survey (LoCuSS), for which deep XMM-Newton observations are available. We
characterise the structure of the X-ray surface brightness distribution of each
cluster by measuring both their power ratios and centroid shift, and thus rank
the clusters by the degree of substructure. These complementary probes give a
consistent description of the cluster morphologies with some well understood
exceptions. We find a remarkably tight correlation of regular morphology with
the occurrence of cool cores in clusters. We also compare our measurements of
X-ray morphology with measurements of the luminosity gap statistics and
ellipticity of the brightest cluster galaxy (BCG). We check how our new X-ray
morphological analysis maps onto cluster scaling relations, finding that (i)
clusters with relatively undisturbed X-ray morphologies are on average more
luminous at fixed X-ray temperature than those with disturbed morphologies, and
(ii) disturbed clusters have larger X-ray masses than regular clusters for a
given temperature in the M-T relation. We also show that the scatter in the
ratio of X-ray and weak lensing based cluster mass measurements is larger for
disturbed clusters than for those of more regular morphology. Overall, our
results demonstrate the feasibility of assembling a self-consistent picture of
the physical structure of clusters from X-ray and optical data, and the
potential to apply this in the measurement of cosmological cluster scaling
relations.