Before fitting, you must prepare your set of model spectra in a way
that the program can understand.
Yafit understands a number of model formats, including outputs
from certain spectral simulation codes.
You can either provide your models in one of these formats directly
or convert them to the special
.ymod format prior to use.
copymodel task can convert
from the various foreign model formats to
optionally applying custom transformations to the data.
Even if your model data is in one of the formats that Yafit understands,
you may wish to use
copymodel so as to apply these
additional conversions, for instance annotating or modifying the units
on the X (wavelength) or Y (flux) axes to match those presented in the
Here is an example invocation of
yafit copymodel ifmt=galaxev in=bc2003_salp.a1 in=bc2003_salp.a2 xname=Wavelength xunit=Angstrom yname=Luminosity yunit=erg/s y=3.826e33*y out=gal.ymodIn detail, this works as follows:
galaxevis one of the formats that Yafit understands (see Section 4).
copymodeltask is given in Appendix A.1.
Having prepared your .ymod file, you can view it using the
plotmodel command if you wish
before using it for actual fitting.