Documentation on zeestat

Task: zeestat
Purpose: Fits Zeeman parameters to I and V cubes
Categories: model fitting

        ZEESTAT is a Miriad task that fits Zeeman parameters to a region of
        input I and V cubes. Zeestat also analyses the noise correlations
        to determine a factor used in correcting the sigma estimates.

Key: iin
        Input I cube in vxy order. Wild card expansion is supported. No default.

Key: vin
        Input V cube in vxy order. Wild card expansion is supported. No default.

Key: beam
        The beam of the observation. This is used in determining the sigma
        correction factor. The default is a delta function. You should
        give the beam if you want an accurate estimate of sigma.
        Wild card expansion is supported. 

Key: rho
        The channel-to-channel correlation coefficient. This is used in
        determining the sigma correction factor. The default is 0.

Key: freq
        Frequency (GHz) of splitting. No default.

Key: mode
        This is a character string that determines the algorithm used in the
        fitting process. It consists of several flags, which can be:
          m Use maximum likelihood technique.
          l Include a leakage term in the fitting.
          2 Use a two sided derivative estimate.
          x Perform extra checks for better solutions when using the maximum
            likelihood technique.
        The default is ' ' i.e., least squares and 1.

Key: aveop
        If 'a' then the spectra specified by the spatial window are
        averaged before being passed to the fitting routine.  Otherwise,
        and by default, all spectra are passed to the fitting routine
        and "spatial summing" (as defined by SKLZ) is performed.

Key: chan
        Channel range. Default is all channels.

Key: blc
        Bottom left corner of spatial region to examine. Default is (1,1).

Key: trc
        Top right corner of spatial region to examine. Default is all
        of image.

Key: log
        This is the name of an output logfile, which shows how the error
        estimate varies with the alpha parameter.

Key: out
        Output results to this file as well as screen