XMM-Newton (cross)-calibration
  ESA's large X-ray space observatory XMM-Newton is in its fifth year of operations. We give a general overview of the status of calibration of the five X-ray instruments and the Optical Monitor. A main point of interest in the last year became the cross-calibration between the instruments. A cross-calibration campaign started at the XMM-Newton Science Operation Centre at the European Space Astronomy Centre in collaboration with the Instrument Principle Investigators provides a first systematic comparison of the X-ray instruments EPIC and RGS for various kind of sources making also an initial assessment in cross calibration with other X-ray observatories. 
M.G.F. Kirsch, B.Altieri, B. Chen, F. Haberl, L. Metcalfe, A.M.T.   Pollock, A.M. Read, R.D. Saxton, S. Sembay, M.J.S. Smith