Thermal emission from pulsars to constrain the neutron star equation of state

Several methods exist to measure the masses and the radii of neutron stars andthus constrain the equation of state, but almost 50 years after their discoverythe nature of neutron star matter is still unknown. One way to constrain themass and the radius is to model the Xray pulse profile of low magnetic fieldmillisecond pulsars (MSPs), showing predominantly thermal emission and with veryprecise mass measurements. However, only four thermally emitting MSPs are knownand just one has a precisely known mass. We request observations of two moreMSPs with precisely known masses, to determine if their spectra are thermal.These MSPs can then be used to constrain the nature of neutron star matter,providing complementary information to laboratory data. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]