An image reconstruction method for an X-ray telescope system with an angular resolution booster

We propose an image reconstruction method for an X-ray telescope system with an angular resolution booster proposed by Maeda et al.(2018). The system consists of double multi-grid masks in front of an X-ray mirror and an off-focused two-dimensional imager. Because the obtained image is off-focused, additional image reconstruction process is assumed to be included. Our image reconstruction method is an extension of the traditional Richardson-Lucy algorithm with two regularization terms, one for sparseness and the other for smoothness. Such a combination is desirable for astronomical imaging because astronomical objects have variety in shape from point sources, diffuse sources to mixtures of them. The performance of the system is demonstrated with simulated data for point sources and diffused X-ray sources such as Cas A and Crab Nebula. The image resolution is improved from a few arcmin of focused image without the booster to a few arcsec with the booster. Through the demonstration, the angular resolution booster with the image reconstruction method is shown to be feasible.

[1]  J. Hughes,et al.  X-Ray Measurements of the Particle Acceleration Properties at Inward Shocks in Cassiopeia A , 2017, 1710.06992.

[2]  H. Krawczynski,et al.  Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes , 2016, 1609.09490.

[3]  Hideyuki Mori,et al.  First peek of ASTRO-H Soft X-ray Telescope (SXT) in-orbit performance , 2016, Astronomical Telescopes + Instrumentation.

[4]  Yoshiharu Namba,et al.  The ASTRO-H (Hitomi) x-ray astronomy satellite , 2016, Astronomical Telescopes + Instrumentation.

[5]  Shiro Ikeda,et al.  Bin mode estimation methods for Compton camera imaging , 2013, 1312.4291.

[6]  Marc Teboulle,et al.  A Fast Iterative Shrinkage-Thresholding Algorithm for Linear Inverse Problems , 2009, SIAM J. Imaging Sci..

[7]  F. Aharonian,et al.  Fast Variability of Nonthermal X-Ray Emission in Cassiopeia A: Probing Electron Acceleration in Reverse-Shocked Ejecta , 2008, 0803.3410.

[8]  Ryuichi Fujimoto,et al.  The X-Ray Observatory Suzaku , 2007 .

[9]  T. R. Gosnell,et al.  Digital Image Reconstruction: Deblurring and Denoising , 2005 .

[10]  Fionn Murtagh,et al.  Deconvolution in Astronomy: A Review , 2002 .

[11]  Martin C. Weisskopf,et al.  Chandra X-ray Observatory (CXO): overview , 1999, Astronomical Telescopes and Instrumentation.

[12]  J. Hughes,et al.  Nucleosynthesis and Mixing in Cassiopeia A , 1999, The Astrophysical journal.

[13]  L. Lucy.  An iterative technique for the rectification of observed distributions , 1974 .

[14]  William H. Richardson,et al.  Bayesian-Based Iterative Method of Image Restoration , 1972 .