Abstract for Proposal 096132
X-ray pulse waveform of an accreting ms pulsar and the NS equation of state
Modelling the waveform of the X-ray pulsations of accreting ms pulsars
(AMSP) is one of the most promising ways to constrain the equation of
state of neutron stars. This requires collecting many photon counts
to break the degeneracy between the several parameters that shape
pulse profiles. The polarimetric information granted by IXPE eases the
requirement by independently measuring the geometry of the hot spots. We
propose a 110 ks XMM-NuSTAR ToO observation of the next outburst of an
AMSP to measure the pulsar ephemeris and fold simultaneous IXPE data,
model the broadband spectrum, and derive a high statistics energy-resolved
pulse profile. The proposed observation will measure the mass and the
radius with an accuracy of a few per cent.
Details on Observing Strategy and Trigger Criteria
ToO observation of an X-ray outburst of an AMSP triggered by an X-ray
flux >3E-10 erg/cm2/s (0.5-10 keV). Reaction time < a week to ensure the
maximum scientific return. A simultaneous NuSTAR observation is requested
(only one trigger).