SExtractor flags:
----------------

1     The object has neighbors, bright and close enough to 
      significantly bias the photometry, or bad pixels 
      (more than 10% of the integrated area affected).

2     The object was originally blended with another one.

4     At least one pixel of the object is saturated 
      (or very close to).

8     The object is truncates (to close to an image boundary).

16    Object's aperture data are incomplete or corrupted.

32    Object's isophotal data are incomplete or corrupted.

64    A memory overflow occurred during deblending.

128   A memory overflow occurred during extraction.


An object close to an image border may have FLAGS = 16, 
or perhaps FLAGS = 8+16+32 = 56.