ROSITA - ROentgen Survey with an Imaging Telescope Array

ROSITA is a mission being studied jointly by ESA's Human Spaceflight and Science Directorates. The intention is to perform an all-sky medium energy X-ray survey by placing an array of sensitive X-ray telescopes on ESA's Columbus module on the International Space Station. ROSITA will continue the pioneering work of European scientists on X-ray surveys using the German/US/UK ROSAT observatory which completed the first all-sky imaging survey. Because of technology limitations at the time, ROSAT was only sensitive below 3 keV, where the effects of absorption are strongest in the X-ray band. The ROSITA Principal Investigator is Prof. G. Hasinger who leads a team of scientists from MPE Garching, AIT Potsdam, and the IAA Tubingen. The proposed ROSITA survey will have a hundred times more senstivity and a hundred times better angular resolution than the previous 2-10 keV survey which was performed in the 1970's by the non-imaging HEAO-A2 instrument.

During the 3 year lifetime, ROSITA will detect around 50,000 sources above 2 keV. These will be mainly AGN, half of which will be completely unknown. ROSITA is expected to find several 10,000 clusters of galaxies. X-ray and optical measurements of such a large sample of clusters will allow the nature of dark matter to be sensitively probed. This is because the X-ray cluster emission is dominated by hot gas trapped in the deep, dark matter dominated, gravitational field. ROSITA will also contribute to galactic science by studing the hard emission from stellar coronae, stellar flares embedded protostars and X-ray binaries.

The ROSITA telescope will consist of seven 27-fold nested mirrors and a novel form of CCD detector being developed at MPE. Following an internal ESA study that confirmed the overall feasibility of accommodating ROSITA on the ISS, ROSITA has been approved for a Phase A study which is expected to start during 2004.