Upper: fit of the EPIC-pn spectrum combined from the first four XMM-Newton observations to a power law absorbed by the Galactic column of 1.9 × 10²⁰ cm⁻². Lower: spectra from the first Swift observation (September 12, 2016; black), the XMM-Newton observations of November 27, 2016 (green) and April 25, 2018 (blue), and the combined data from Swift between February 15, 2017 and August 14, 2017 (red), all fitted with a power law of Γ = 2.58 absorbed by the Galactic column. Residuals to the fits are shown below.