Deconvolution of Images Taken with the Suzaku X-Ray Imaging Spectrometer
Abstract
We present a non-iterative method to deconvolve the point spread function (PSF) from images taken with the Suzaku X-ray Imaging Spectrometer (XIS). The method is optimized for analyses of extended sources with high photon statistics. Suzaku has four XIS detectors, each with its own X-ray CCD and X-Ray Telescope (XRT), and has been providing opportunities in spatially-resolved analyses of extended objects. The detectors, however, suffer from broad and position-dependent PSFs with their typical half-power diameter (HPD) of ∼110''. The present method is intended to recover spatial resolution to ∼15'' over a dynamic range of around 1:100 in the brightness without assuming any source model. Our deconvolution proceeds in two steps: An XIS image is multiplied by the inverse response matrix, calculated from its PSF after rebinning CCD pixels to larger-size tiles (typically 6'' × 6''). The inverted image is then adaptively smoothed. The PSF is modeled on a ray-tracing program and an observed point-source image. The method has been applied to images of Centaurus A, PSR B1509-58 and RCW 89 taken by one XIS (XIS1). The results have been compared with images taken with Chandra to conclude that the spatial resolution has been recovered to ∼20'' down to regions where the surface brightness is about 1:50 of the brightest tile. We believe the spatial resolution and the dynamic range can be improved with higher fidelity PSF modeling and higher precision pointing information.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- January 2009
- DOI:
- 10.1093/pasj/61.sp1.S55
- arXiv:
- arXiv:0805.3074
- Bibcode:
- 2009PASJ...61S..55S
- Keywords:
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- method: data analysis;
- techniques: image processing;
- X-rays: general;
- Astrophysics
- E-Print:
- 21 pages, accepted for publication in PASJ. A PS file with original-quality figures is available at http://www.slac.stanford.edu/~sugizaki/preprint/pasj3256/sugizaki_No3256.ps