We present results of the point spread function (PSF) calibration of the hard X-ray optics of the Nuclear Spectroscopic Telescope Array (NuSTAR). Immediately post-launch, NuSTAR has observed bright point sources such as Cyg X-1, Vela X-1, and Her X-1 for the PSF calibration. We use the point source observations taken at several off-axis angles together with a ray-trace model to characterize the in-orbit angular response, and find that the ray-trace model alone does not fit the observed event distributions and applying empirical corrections to the ray-trace model improves the fit significantly. We describe the corrections applied to the ray-trace model and show that the uncertainties in the enclosed energy fraction (EEF) of the new PSF model is less than or similar to 3 for extraction apertures of R greater than or similar to 60" with no significant energy dependence. We also show that the PSF of the NubSTAR optics has been stable over a period of similar to 300 days during its in-orbit operation.
|Location||Palais des congrés de Montréal Montréal, Quebec, Canada|
|Period||22/06/2014 → 27/06/2014|
|Series||Proceedings of S P I E - International Society for Optical Engineering|
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- X-ray optics
- Point Spread Function (PSF)
- Half Power Diameter (HPD)