MAKIMG -- make a starting image for doppler tomography or for simulating
data.
FIGARO variables:
IMAGE -- The name of the image file to create
NSIDE -- Size of images (which are square)
VPIX -- Size of pixels in km/s. The product of NPIX and VPIX should
more than cover the FWZI of the line of interest. VPIX should
be less than or equal to the km/s/pixel of the data. Note there
is no problem if VPIX is much smaller, except in the extra
CPU and memory required.
NIMAGE -- Number of images. Blended lines can be dealt with by assigning
an image for each line, although it is also possible for the
same image to represent more than one line.
NWAVE -- Number of lines. e.g you could map the Paschen series and the
CaII triplet with 2 images, one for CaII and one for the
hydrogen lines, but you would have to specify a wavelength for
each line to be mapped.
WAVE(NWAVE) -- Central wavelengths in Angstroms
If (NWAVE .NE. NIMAGE)
NWHICH(NWAVE) -- Defines which image corresponds to each line
SCALE(NWAVE) -- Defines scale factor to apply to each line (allows for
different lines to have same image but a different
scaling.) These values can be optimised outside MEM
using optscl.
FWHM -- Full width half maximum of instrument, km/s. Don't make too
large or it will be attempting an impossible deconvolution.
Too small does not matter, but a finite FWHM is good for
smoothing out numerical noise.
GAMMA -- Systemic velocity of system km/s.
NSUB -- Subdivision factor to account for finite exposure length.
Each exposure will be divided into NSUB exposures uniformly
spread through the exposure and then trapezoidally averaged.
If your exposures are short, set = 1. If you do use it, only
apply towards the end of the iterations because it slows things
down. The effect of NSUB has never quite satisfied me to be
honest.
OFFSET -- Constant to add to all phases to account for zero point
error in the ephemeris. This rotates the entire image but
the image must be re-iterated after any change to OFFSET.
NDIV -- The projection is first done onto a fine grid which is then
blurred and binned onto the final array. This is faster
than blurring each pixel of the image directly onto the coarse
grid. NDIV is the factor by which each coarse pixel is split.
NDIV must be large enough so that the FWHM is well sampled.
e.g if FWHM=2, then NDIV>2 should be used.
However there is no reason not to change NDIV as you iterate
and you could for example start with NDIV = 1 and only raise
it for the final few iterations. Note that large NDIV values
will slow things down so be careful.
(use 'setobj 5 image.more.doppler.ndiv' to set ndiv = 5 for
example)
NB This used to be called DIVI a real parameter but the binning
part which has changed from before is much easier with integer
sub-division which is what I always used anyway. For old
images you may have to use
creobj '_INTEGER' file.more.doppler.ndiv' and
setobj 3 file.more.doppler.ndiv
to set its value.
USE -- This specifies whether the HJDs or phases should be used
to compute the phases during iterations. Although HJDs
allow you to vary the ephemeris with HJD0 and PERIOD,
those which come from phase folding inside molly will be
INCORRECT as far as phases are concerned (imagine averaging
the HJDs of two spectra taken one cycle apart). Normally you
should use the phases therefore. The two options are
HJDs -- use HJDs
Phases -- use phases
or any shortening of them.
Old style images do not have this parameter. By default in
these cases the phases and then the HJDs will be searched for.
Now parameters defining shape of image:
FANCY -- .TRUE. then you want more than just a constant. The fancy
option allows you to combine a gaussian spot, a spiral pattern
and a power law in radius.
if(FANCY)
XCEN -- X centre of gaussian spot (km/s)
YCEN -- Y centre of gaussian spot (km/s)
WIDTH -- FWHM of gaussian spot (km/s)
PART -- Fraction of total flux from gaussian
XSP -- X centre of spiral pattern and power law disc (km/s)
YSP -- Y centre of spiral pattern and power law disc (km/s)
VLOW -- Lowest disc velocity (outer disc) (km/s)
VHIGH -- Highest disk velocity (inner disc) (km/s)
EXPON -- exponent between them (intensity scales as V**EXPON)
ANGLE -- Opening angle of two armed spiral pattern (degrees)
CURVE -- Difference in angle between outer and inner velocities
FRACT -- Fraction of total flux at a particular radius contained
in spiral relative to power law
TOTAL -- Sum of emission over image.
This command belongs to the classes: