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| Paper: |
Image Fidelity |
| Volume: |
217, Imaging at Radio Through Submillimeter Wavelengths |
| Page: |
344 |
| Authors: |
Wright, M. |
| Abstract: |
This paper discusses errors in images of complex sources such as the supernova remnant Cas A. We compared images from 1.4 to 83 GHz to look for spectral index variations across Cas A. The 83 Ghz image combines interferometer data from 75 to 87 GHz and 19 pointing centers, with single dish data to form a well sampled image. Significant large angular scale differences are apparent in these images. Image errors result from instrumental effects such as different uv-sampling, primary beam and pointing errors, calibration and image processing errors. Analysis of these images shows that the images have errors at the 1% to 2% level, in agreement with the empirical estimates from the ensemble of images made using in the course of the data reduction. We made an model study of images of Cas A and other complex sources to determine how the mosaicing and uv-sampling affects the image fidelity - i.e. how well the image represents the real source distribution. These results suggest that it is quite difficult to achieve an image fidelity much better than 1%. |
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