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UV_FIT

        [ADVANCED\]UV_FIT   [Func1 .. FuncN]  [/QUIET] [/SAVE File] [/WIDGET
    N]

    Fit UV data with a few simple functions. Func1 to FuncN (currently  N  <
    5)  are  the  names of the functions to be fitted. If not specified, the
    last names (or those attributed by the /WIDGET options) are used.

    The models are either simple functions or linear combinations of  simple
    functions.   The results of the fitting process are the position offsets
    in R.A. and Dec (in arc second) of the model source from the phase  ref-
    erence  center,  and  its flux (Jansky).  Depending on the fitting func-
    tions additional fit results are possible. Currently supported distribu-
    tions and additional fit parameters are:
    POINT     Point source              : None
    E_GAUSS   Elliptic Gaussian source  : FWHM Axes (Major and Minor), Pos Ang
    C_GAUSS   Circular Gaussian source  : FWHM Axis
    C_DISK    Circular Disk             : Diameter
    E_DISK    Elliptical (inclined) Disk: Axis (Major and Minor), Pos Ang
    RING      Annulus                   : Diameter (Inner and Outer)
    EXPO      Exponential brightness    : FWHM Axis
    POWER-2   B = 1/r^2                 : FWHM Axis
    POWER-3   B = 1/r^3                 : FWHM Axis
    E_RING    Inclined Annulus          : Inner, Outer, Pos Ang, Ratio
    E_EXPO    Elliptic exponential       : FWHM Axes (Major and Minor), Pos Ang
    SPERGEL   Spergel brightness profile : FWHM Axis, nu
    E_SPERGEL Elliptic Spergel profile   : FWHM Axes (Maj. and Min.), Pos Ang, n


    The  function  parameters  are found in a SIC structure named UVF% under
    names UVF%PARi%PAR[7]  (starting  values),  UVF%PARi%RANGE[7]  (starting
    ranges)  and UVF%PARi%START[7] (number of starts). The /WIDGET option is
    a convenient way to set these variables.

    UV_RESIDUAL will compute the fit residual when used after UV_FIT,  while
    it  computes  the  residual  from the Clean component list if used after
    CLEAN.

    WRITE UV_FIT file[.uvfit] will save the fit results in a  GILDAS  table,
    in the same format than that of the UV_FIT task.

    The  Pos  Ang (PA) are the Position Angles of the major axis of the dis-
    tribution. To deproject the elliptical shapes, one should use the  Posi-
    tion Angle of the rotational axis, PA-90 (see commands UV_CIRCLE, UV_DE-
    PROJECT and UV_RADIAL)


Subsections

Gildas manager 2023-06-01