XMM-Newton

The X-ray Multi-Mirror Mission (now called XMM-Newton) was launched by the European Space Agency in December 1999. It possesses three grazing incidence X-ray telescopes with CCD detectors (the European Photon Imaging Camera; EPIC) in each focal plane. XMM-Newton is complementary to Chandra in the sense that, while not possessing the high spatial resolution of Chandra (it can achieve spatial resolutions of $\sim 5$arcsec), it has a significantly larger collecting area thereby allowing high-throughput spectroscopy. Since many studies of X-ray reflection in accreting black holes are signal-to-noise limited, XMM-Newton has become an extremely important observatory for these purposes. Two of the telescopes also have (reflection) diffraction gratings that permanently intercept half of the X-ray beam in two of the telescopes, providing simultaneous high-resolution (up to $E/\Delta E\sim 500$) X-ray spectra in the soft X-ray band (below 2keV).