The probability distribution of 3D shapes of galaxy clusters from 2D X-ray images

ABSTRACT We present a new method to determine the probability distribution of 3D shapes galaxy clusters from 2D images using stereology. In contrast conventional approach combining different data sets (such as X-rays, Sunyaev–Zeldovich effect, and lensing) fit model cluster for each cluster, our requires only single set, such X-ray observations or effect observations, consisting sufficiently large number clusters. Instead reconstructing shape an individual object, we recover function (PDF) observed The PDF is relevant statistical quantity, which can be compared with theory used test cosmological models. apply this publicly available Chandra 89 well-resolved Assuming ellipsoidal shapes, find that sample mixture prolate oblate preference oblateness most probable ratio principle axes 1.4 : 1.3 1. assumption not essential directly applicable non-ellipsoidal shapes. Our insensitive radial density temperature profiles cluster. sensitive changes in emitting gas inner outer regions evidence variation distance centre.