regions in the higher order maps. An example of this process is shown in Figure \[separate\], where two blended sources are identified by FOF as one in panels 1 to 4, and finally as two separate sources in panel 5. A source is tagged as blended whenever its source region includes more than one source in one of the higher order maps.

At this point we had a list of sources virtually free from blending. Their positions were assigned by searching for the pixel whose $3\times 3$ square island has the largest number of photons. Then we separated the blended sources among the most reasonable non-overlapping source regions, without assuming a source brightness model. This is obtained as follows. For each pair of blended sources, we can find a threshold above which they are detected without overlapping pixels. Sorting all occupied pixels by their photon densities, we identify the pixel with the lowest value whose inclusion causes the bridging of the two sources. This pixel is flagged as a [*bridge pixel*]{} and is removed from the original image. After a [*bridge pixel*]{} is found and removed, we again run FOF on all occupied pixels above local background. Unless the sources 