NICER observation list: Target ID 363703

Pulsating Ultra-Luminous X-ray sources (PULXs) are a recently discovered class of sources in which a pulsating Neutron Star (NS) is radiating well above the isotropic Eddington luminosity. Their high spin-up rates make them perfect targets for testbeds of accretion models and and accretion-driven spin-up in NSs, plus NS interior structure study. Moreover, pulsations in this class of objects is transient, and deserves dedicated observations in order to sample and study hysteresis behaviour in which similar flux levels show very different pulsed fractions. We identified three PULXs that are particularly well suited for such studies. Thanks to its high large effective area and our flexible observing plan, NICER will allow to meet our objectives within relatively short exposure times.