CLEAN_ARES

    This  is the minimal flux in the dirty map that the program will consider as
    significant.  Alternatively, the threshold can be specified as a fraction of
    the peak flux using CLEAN_FRES.  Once this level has been reached  the  pro-
    gram stops subtracting, and starts the restoration phase.  The unit for this
    parameter is the map unit (typically Jy/Beam).  The parameter should usually
    be of the order of magnitude of the expected noise in the clean map.

    If 0, CLEAN_FRES will be used instead. If all of CLEAN_NITER, CLEAN_ARES and
    CLEAN_FRES are 0, an absolute residual equal to the noise level will be used
    for CLEAN_ARES.

    Short form is ARES.

    This  may  be  overseded by the /ARES option which imposes a limit per plane
    through an array of values.