Radio-quiet neutron star ten bodies have been proposed as rotation-powered neutron stars that are not visible as radio sources, but are visible as x–ray and gamma ray sources. Indicators that they are indeed neutron stars include them having a high x-ray to lower frequencies emission ratio, a constant x-ray emission profile, and coincidence with a gamma ray source. Quark stars, theoretical neutron star-like objects composed of quark matter, may be radio quiet, according to some theories. More plausibly, however, radio-quiet neutron stars may simply be pulsars which do not pulse in our direction. As pulsars spin, it is theorized they emit radiation from
The Magnificent Seven (neutron stars) star radius. Reality is somewhat more complicated, but this oversimplified analysis catches the essence of what is needed in order to measure the neutron star radius: distance, flux and surface temperature. Observing the star thermal emission is therefore crucial. Among all thermally emitting neutrons stars the Magnificent Seven are the only ones with a purely blackbody spectrum. Their clean thermal emission, unmarred by contamination from magnetospheric activity, a surrounding nebula or supernova remnant, makes these sources ideal targets for such a study. Despite many attempts, no radio emission is detected from these sources. The preliminary results from latest deep search