Basic Information on zeemap

Task: zeemap
Purpose: Map the magnetic field from I and V cubes
Categories: profile analysis

        ZEEMAP tries to find the line-of-sight magnetic field splitting
        a transition by measuring the shift in the line owing to the
        Zeeman effect.
 

Key: iin
        Stokes I spectral cube with channel on the first axis.

Key: vin
        Stokes V spectral cube with channel on the first axis.

Key: b
        Output file name for line-of-sight magnetic field.

Key: d
        Output file name for the derivative of I/2 spectrum (op=div
        only).

Key: be
        Output file name for the error in B (op=div only).

Key: g
        Output file name for amount of residual I found in V (op=fit
        only).

Key: blc
        Bottom left corner of box to be fit.

Key: trc
        Top right corner of box to be fit.

Key: freq
        Frequency of line in GHz, used to determine amount of splitting
        per Gauss.

Key: op
        Operation code that controls how the line shift is determined -
          div: by dividing V by the derivative of I/2, or
          fit: by fitting of the derivative of I and I to V.

Key: cutoff
        For op="div", the division will not be performed unless the
        derivative of I/2 is greater than cutoff.
        For op="fit", the fit will not be performed unless one or more
        channels in the I spectrum is larger in absolute value than
        cutoff.

Key: vrms
        RMS deviation in V spectrum in a signal free area.  This can
        be obtained using histo.  Used for calculating error in B
        for op=div.

Key: mode
        This determines the algorithms used, if operation="fit". It
        can consist of several flags:
         l  Include leakage term,
         2  Use 2 sided derivative approximation,
         m  Use maximum likelihood technique,
         x  Perform extra checks for better solutions, when
            using the maximum likelihood technique.
        Default mode=2m.

Key: y corlen
        Correlation length.  Selected window must be divisible by this
        number, which is the number of pixels over which you think the
        magnetic field might be constant.  Default is 1, try maybe 2
        or 4.
 
Revision: 1.4, 2010/11/22 05:06:16 UTC