NICER / ISS Science Nugget for February 28, 2019

Scientific American heralds NICER's study of neutron star interiors

The cover story of the March 2019 issue of Scientific American magazine (see figure) concerns NICER's work to help reveal the inner workings of neutron stars. These stars are the densest objects in the universe, with a mass of up to 2 Suns squeezed into the volume of a city. The exact density in the core of a neutron star constrains the physical theories that describe the interactions of large numbers of neutrons and other sub-atomic particles.

For four neutron stars, NICER has accumulated very deep exposures -- millions of seconds, built up in hundreds of individual observations made during separate ISS orbits. These data are being analyzed with supercomputers to assess and model the pulsations that reach Earth from the stars' sweeping emission beams. Small deviations in the received pulse shapes due to light "bending" in the strong gravity near ultra-compact objects encode information about the mass and radius of each neutron star. NICER is close to releasing the initial results of this analysis. The Scientific American article provides context and demonstrates the science community's interest in this work.