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Theses Doctoral

HEFT measurement of the hard X-ray size of the Crab Nebula and the hard X-ray optics of the Nuclear Spectroscopic Telescope Array (NuSTAR)

An, Hongjun

In this thesis, I discuss two topics: The High Energy Focusing Telescope (HEFT) and the Nuclear Spectroscopic Telescope Array (NuSTAR). HEFT is the first experiment done with imaging telescopes in the hard X-ray energy band (~20-70 keV). I briefly describe the instrument and the balloon campaign. The inflight calibration of the Point Spread Function (PSF) is done with a point source observation (~50 minutes of Cyg X-1 observation). With the PSF calibrated, I attempt to measuring the size of the Crab Nebula in this energy band. Analysis for aspect reconstruction, optical axis determination and the size measurement are described in detail. The size of the Crab Nebula is energy dependent due to synchrotron burn-off. The measurement of the size at different energies can provide us with important parameters for the pulsar wind nebula (PWN) model such as the magnetization parameter. With ~60 minutes of observation of the Crab Nebula with HEFT, I measure the size of the Crab Nebula at energies of 25-58 keV. The analysis technique I used for the size measurement here can be used for measuring the size of astrophysical objects whose sizes are comparable to the width of the PSF. NuSTAR is a satellite version of the HEFT experiment although the spatial and spectral resolution of the optics are improved significantly. And thus, the fabrication technique for the HEFT optics needed to be modified. I describe the fabrication technique for the NuSTAR optics, focusing on the epoxy selection and process development and the metrology systems for characterizing the figure of the glass surfaces.


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More About This Work

Academic Units
Thesis Advisors
Hailey, Charles J.
Ph.D., Columbia University
Published Here
November 9, 2011