Write in . The photon count ratio in d eliminates radius, electron number density and the common normalization:The extra is essential for a photon number spectrum. HenceThe measured central Compton y parameter and the supplied conversion coefficient then determine a column combination:To determine the two remaining quantities separately, define and . Use , , , , and in d. With the spectral unit conversion explained there, the count luminosity isExplicitly the numerical coefficient isSince , substitution gives , soRounding consistently with the supplied coefficient , the cluster has , and . Substituting the unrounded values into both X-ray count luminosities gives and , and the central Compton y parameter returns . If the observed were a projected-disk average, its central value would be times larger and this same inversion would give smaller by and larger by ; specifying the sightline is therefore part of the inference.