Hitomi HXT deconvolution imaging of the Crab Nebula dazzled by the Crab pulsar.

This article presents a novel image deconvolution method developed to recover high-resolution images of the Crab Nebula taken by the Hitomi Hard X-ray Telescope (HXT), effectively suppressing artifacts caused by the bright Crab pulsar. The method extends the Richardson–Lucy algorithm by simultaneously deconvolving multi-pulse-phase images and separating the nebula and pulsar components using smoothness and flux regularizations, respectively. Applying this technique to Hitomi HXT data in energy bands from 3.6 to 70 keV, the authors confirm known structures such as the torus and jets consistent with Chandra X-ray observations below 15 keV, and independently verify NuSTAR's finding that the nebula size decreases at higher energies. The approach also reveals that the north-east side of the nebula dims more rapidly with increasing energy, and the algorithm is adaptable to other telescope images of faint diffuse objects containing bright point sources.