zeemap - Map the magnetic field from I and V cubes
ZEEMAP tries to find the line-of-sight magnetic field splitting
a transition by measuring the shift in the line owing to the Zeeman
Stokes I spectral cube, with axes in order Channel, X, Y.
Stokes V spectral cube, with axes in order Channel, X, Y.
Output file name for Line-of-sight magnetic field.
Output file name for amount of residual I found in V (FIT only)
Output file name for the derivative of I/2 spectrum (DIV only)
Output file name for the error in B (DIV only)
Bottom left corner of box to be fit
Top right corner of box to be fit
Frequency of line in GHz. This is used to determine amount of
splitting per Gauss.
Operation code. Possible values are ``div'' and ``fit''. For
``div'', the line shift is determined by dividing V by the
derivative of I/2. For ``fit'', the line shift is determined
by fitting of the derivative of I and I to V.
For ``div'', the division will not be performed unless the
derivative of I/2 is greater than cutoff.
For ``fit'', the fit will not be performed unless one or more
channels in the I spectrum is larger in absolute
value than cutoff.
RMS deviation in V spectrum in a signal free area. This can easily
be gotten using histo. Used for calculating error in B for op=div.
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.
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.