084384

The recent discovery of a handfuln of ULXs showing pulsations openParPULXsclosePar unambiguously associated them to neutron stars openParNSsclosePar exceeding up to about 500 times their L_Edd. During AO17 we were awarded a LP aimed at searching for new PULXs within 8 fields containing promising candidates. So far we obtained data for half of sample and we discovered one new PULX. This result confirms the goodness of the LP adopted strategy and that a relatively large fraction of ULXs likely hosts an accreting NS. The present proposal is aimed at observing two bright openParhigh fluxclosePar ULXs in Timing mode and at looking for coherent signals over a period range openPar1ms<P<100msclosePar. The detection of even one very fast PULX would be very important for constraining NS accretion models as well as binary systems.