Atomic data for astrophysics: Fe xiii soft X-ray lines

Abstract

We present new large-scale R-matrix (up to n = 4) and distorted wave (up to n = 6) scattering calculations for electron collisional excitation of Fexiii. We aim to provide accurate atomic data for the soft X-rays, where strong n = 4 → n = 3 transitions are present. As found in previous work on Fex, resonances from within the n = 4 levels and cascading from higher levels significantly increase the intensities of these lines. We provide a number of models and line intensities, and list a number of strong unidentified lines.