High resolution X-ray Timing from a LOFT

LOFT (Large area Observatory For X-ray Timing) is an innovative mission concept for a next generation of X-ray timing experiments. Recent developments in the field of Silicon detectors allow to design a realistic observatory devoted to X-ray timing studies with an effective area around 13 m2, in the energy range 2-30 keV. In this paper we present the mission concept together with the key properties of the detectors, as demonstrated in our laboratory, including an energy resolution better than 500 eV at room temperature. The overall power and weight budgets fit to a standard mission design. Such an exceedingly large area (>20 times RXTE/PCA), with a time resolution better than 10 ms, will allow unprecedently fast and accurate time variability studies related to accreting compact objects (e.g. fast coherent pulsations and QPOs). We describe here the scientific performance of a timing observatory in the 10 m2 class for open problems in fundamental physics, such as strong gravity effects, the measurement of the mass of black holes and neutron stars, the equation of state of ultradense matter. Finally, we present the results of simulated LOFT observations.