How do atomic code uncertainties affect abundance measurements in the
  intracluster medium?
  Accurate chemical abundance measurements of X-ray emitting atmospheres
pervading massive galaxies, galaxy groups, and clusters provide essential
information on the star formation and chemical enrichment histories of these
large scale structures. Although the collisionally ionised nature of the
intracluster medium (ICM) makes these abundance measurements relatively easy to
derive, underlying spectral models can rely on different atomic codes, which
brings additional uncertainties on the inferred abundances. Here, we provide a
simple, yet comprehensive comparison between the codes SPEXACT v3.0.5 (cie
model) and AtomDB v3.0.9 (vapec model) in the case of moderate, CCD-like
resolution spectroscopy. We show that, in cool plasmas ($kT \lesssim 2$ keV),
systematic differences up to $\sim$20% for the Fe abundance and $\sim$45% for
the O/Fe, Mg/Fe, Si/Fe, and S/Fe ratios may still occur. Importantly, these
discrepancies are also found to be instrument-dependent, at least for the
absolute Fe abundance. Future improvements in these two codes will be necessary
to better address questions on the ICM enrichment.
