The properties of the X-ray corona in the distant ($z=3.91$) quasar APM 08279+5255

E. Bertola, C. Vignali, G. Lanzuisi +7

We present new joint XMM-Newton and NuSTAR observations of APM 08279+5255, a gravitationally-lensed, broad-absorption line quasar ($z=3.91$). After showing a fairly stable flux ($f…