Documentation on mosmem

Task: mosmem
Purpose: Maximum Entropy deconvolution for a mosaiced image
Categories: deconvolution

        MOSMEM is a MIRIAD task which performs a (joint) maximum entropy
        deconvolution of a mosaiced image.

Key: map
        The input dirty map, which should have units of Jy/beam, which was
        produced by INVERTs mosaic mode.

Key: beam
        The input dirty beam, also produced by INVERTs mosaic mode. No
        default

Key: model
        An initial estimate of the deconvolved image. For point sources,
        giving a good initial model may help convergence. In principle,
        this only helps convergence, but should not affect the final
        solution. The model could be the output from a previous run of
        MOSMEM or any other deconvolution task. It must have flux units of
        Jy/pixel. The default is a flat estimate, with the correct flux.

Key: default
        The default image. This is the image that the final solution will
        tend towards. The final result will be influenced by this default
        if the constrains that the data put on the solution are weak.
        The default is a flat estimate, with the correct flux.

Key: out
        The name of the output map. The units of the output will be Jy/pixel.
        It can be input to RESTOR or MOSMEM (as a model, to continue the
        deconvolution process).

Key: niters
        The maximum number of iterations. The default is 30.

Key: region
        This specifies the region to be deconvolved. See the Users Manual
        for instructions on how to specify this. The default is the entire
        image.

Key: measure
        The entropy measure to be used, either "gull" (-p*log(p/e)) or
        "cornwell" (-log(cosh(p)) -- also called the maximum emptiness
        criteria).

Key: tol
        Tolerance of solution. There is no need to change this from the
        default of 0.01.

Key: q
        An estimate of the number of points per beam. MOSMEM can usually
        come up with a good, image-dependent estimate.

Key: rmsfac
        MOSMEM knows the theoretical rms noise of the input dirty map, and 
        will, by default, attempt to reduce the residuals to have an rms of
        this amount. If the true rms noise is different from the theoretical,
        you may give the factor to multiply by to convert from theoretical
        to true rms noise.

        The theoretical rms will usually be an optimistic estimate of the
        true noise level. The true noise will be increased by calibration
        errors, confusion, poorly understood distant sidelobes, etc, so
        rmsfac will usually give some `fudge factor' greater than 1.

Key: flux
        An estimate of the total flux of the source. Giving a good total flux
        will help MOSMEM find a good solution. On the other hand, giving
        a poor value may do harm. Normally MOSMEM will NOT constrain the
        total flux to be this value, but see the ``doflux'' option below.
        The default is image-dependent for measure=gull, and zero for
        measure=cornwell.

Key: options
        Task enrichment parameters. Several can be given, separated by
        commas. Minimum match is used. Possible values are:
          doflux     Constraint the flux to be that given by the "flux"
                     parameter. Normally the "flux" parameter value is only
                     used to determine the default image level.
          verbose    Give lots of messages during the iterations. The default
                     is to give a one line message at each iteration.