Plasma environment effects on K lines of astrophysical interest

Abstract

Aims. In the context of accretion disks around black holes, we estimate plasma-environment effects on the atomic parameters associated with the decay of K-vacancy states in highly charged iron ions, namely Fe XVII– Fe XXV.Methods. Within the relativistic multiconfiguration Dirac–Fock (MCDF) framework, the electron–nucleus and electron–electron plasma screenings were approximated with a time-averaged Debye–Hückel potential.Results. Modified ionization potentials, K thresholds, wavelengths, radiative emission rates, and Auger widths are reported for astrophysical plasmas characterized by electron temperatures and densities in the ranges 105 − 107K and 1018 − 1022cm−3, respectively.Conclusions. We conclude that the high-resolution microcalorimeters on board future X-ray missions such as XRISM and ATHENA are expected to be sensitive to the lowering of the iron K edge due to the extreme plasma conditions occurring in accretion disks around compact objects.