Calibration of the NuSTAR High Energy Focusing X-ray Telescope

Understand

We present the calibration of the \textit{Nuclear Spectroscopic Telescope Array} (\nustar) X-ray satellite.

• We used the Crab as the primary effective area calibrator and constructed a piece-wise linear spline function to modify the vignetting response.
• The achieved residuals for all off-axis angles and energies, compared to the assumed spectrum, are typically better than $\pm 2$\% up to 40\,keV and 5--10\,\% above due to limited counting statistics.
• An empirical adjustment to the theoretical 2D point spread function (PSF) was found using several strong point sources, and no increase of the PSF half power diameter (HPD) has been observed since the beginning of the mission.