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However, the image processing software did not produce any stacked images (combining the exposures) for these southern fields.  The data only got processed to the single-exposure level, so there presumably are no stack detections or other data products derived from the stack images.  There are some individual exposure images in these regions, but those will not be available for download until the DR2 data release (which we are hoping will be completed in 2018January 2019.) 

That is why there can be sources in the catalog that do not have associated stack images available.  These sources should only occur in the far southern sky.

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