XMM-Newton Science Analysis System


evigweight (evigweight-1.8) [xmmsas_20230412_1735-21.0.0]

Event processing

evigweight computes a weight for each photon j falling at detector coordinates $(detx_j,dety_j)$ and of energy (PI) $E_j$ by the inverse of the ratio of the effective area at that position to the central effective area (at the same energy):

  $$w_j \; = \; \frac{A_{0,0}(E_j)}{A_{detx_j,dety_j}(E_j)}$$ (2)

This weight is stored by default as column WEIGHT (the name can be changed setting weightcolname).