... moments

Note that, in general, the center of X-ray emission, the center of tSZ-light and the center of mass do not necessarily coincide in the same point.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... paper

Note that one expects a small (logarithmic) dependence of the observed quadrupole with the map size. This can be easily seen for the case of two point-like clusters, where the asymptotic behaviour of the $\delta T_{{\rm RS}}$ signal goes as r^-2 for large distances r from the center of mass of the system.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.