We report the detection of a complex of narrow X–ray absorption features from the low-mass X–ray binary GX 13 + 1 during 3 XMM-Newton observations in 2000 March and April .
The features are consistent with being due to resonant scattering of the K \alpha and K \beta lines of He- and H-like iron ( Fe xxv and Fe xxvi ) and H-like calcium ( Ca xx ) K \alpha .
Only the Fe xxvi K \alpha line has been previously observed from GX 13 + 1 .
Due to the closeness in energy the Fe xxv and Fe xxvi K \beta features may also be ascribed to Ni xxvii and Ni xxviii K \alpha , respectively .
We also find evidence for the presence of a deep ( \tau \sim 0.2 ) Fe xxv absorption edge at 8.83 keV .
The fits also require the presence of a broad emission feature whose energy and width are poorly determined , partly due to the presence of the deep Fe K \alpha features which severely cut into the feature and partly due to fit differences when using different XMM-Newton instruments .
The equivalent widths of the lines do not show any obvious variation on a timescale of a few days suggesting that the absorbing material is a stable feature of the system and present during a range of orbital phases .