| Research efforts in this thesis are focused on two areas: (1) the High Energy Focusing Telescope (HEFT), a next-generation, focusing, hard X-ray telescope, and (2) the spectral analysis of the isolated neutron star 1E1207.4-5209.;I describe the production, calibration, and flight performance of the High Energy Focusing Telescope (HEFT), a balloon-borne focusing hard X-ray telescope sensitive to X-rays in the 20--70 keV energy band. A number of new technologies were developed and implemented to achieve significant improvements in effective area and angular resolution over previous instruments. HEFT's balloon flight in the Spring of 2005 was highly successful, making HEFT the first focusing hard X-ray instrument to yield scientific results.;The thermal emission from isolated neutron stars provides a clean probe of the extreme physical conditions present at the surface and in the interior of neutron stars. In particular, the identification of spectral features in these spectra can be used to determine neutron star parameters, such as temperature, magnetic field, surface chemical composition, and equation of state. The isolated neutron star 1E1207.4-5209 differentiates itself from all other known neutron stars by possessing multiple X-ray absorption lines. We have reanalyzed the 260 ksec XMM-Newton observation and applied more rigorous statistical analysis to the data. We do not find a third and fourth spectral feature as previously reported in 1E1207.4-5209 with our improved analysis, but only the two broad absorption features. |
