1240014

We propose to perform a 210 ks INTEGRAL ToO observation of a transient millisecond X-ray pulsar in outburst. The target can be either one of the twelve known transient accreting millisecond X-raypulsars in the case of a new outburst or a newly observed object of this class. As these transient sources have broad astronomical interest an outburst will trigger ToO criteria with other X-rayobservatories. These observations can be coordinated in order to study the broad band spectrum in detail from hard to soft X--ray energies as well as the timing properties or eclipsing features of the source during its outburst. This will allow us to disentangle the contribution of soft black bodyreflection (if any) and hard Comptonized spectral components as well as the detection of type-I X-ray bursts or for the first time also burst oscillation at high energy (if present). In particular we will be able to study the energy spectrum in a broad band energy range and with unprecedented high sensitivity above 20 keV. The INTEGRAL observation will also allow a timing analysis to study the pulse profile time lags total and pulsed spectrum in an interesting energy range also for in future planed missions. [truncated! Please see actual data for full text]