Galactic center as seen by XMM-Newton (EPIC-pn) in the 6.3–6.5 keV band (stacking of observations considered in this article). The dashed circular region marks the area used to accumulate the spectra for the energy calibration step. In that region, known massive GMCs reflect the past emission most probably associated with high-activity periods of Sgr A^⋆. The extended emission region encompassing Sgr A^⋆ is the SN remnant Sgr A East. We also highlighted the position of the known transient AX J1745.6-2901, which highly contaminates the flux from the CND region.