Code papers (please cite these if you use Korg):

• Korg: A Modern 1D LTE Spectral Synthesis Package. This is also a good overview of how spectral synthesis works, the inputs and outputs, etc.
• Korg: fitting, model atmosphere interpolation, and Brackett lines

Tutorials:

• Korg basics
• Korg basics in python
• other tutorial notebooks

Example

using Korg, PyPlot

wls, flux, continuum = synth(
    Teff=5000, # effective temperature of 5000 Kelvin
    logg=4.32, # surface gravity of 10^(4.32) cm/s²
    m_H=-1.1,  # metallicity, [m/H]. Overridden for individual elements by alpha_H and individual abundances
    C=-0.5,    # The Carbon abundance, [C/H].  Works for anything from He to U.
    linelist=Korg.get_GALAH_DR3_linelist(),
    wavelengths=(5850, 5900)
)

# plot
figure(figsize=(12, 4))
plot(wls, flux, "k-")
xlabel(L"$\lambda$ [Å]")
ylabel(L"$F_\lambda/R_\mathrm{star}^2$ [erg s$^{-1}$ cm$^{-5}$]");

See the documentation for synth, or the documentation for synthesize for advanced usage.

You can also call Korg from python

See the documentation for setup instructions.

from juliacall import Main as jl
jl.seval("using Korg"); Korg = jl.Korg

# calling Korg.synth is exactly the same as in Julia.
wls, flux, continuum = Korg.synth(
    Teff=5000,
    logg=4.32,
    m_H=-1.1,
    C=-0.5,
    linelist=Korg.get_GALAH_DR3_linelist(),
    wavelengths=(5850, 5900)
)

Multithreading

Korg can use multithreading to speed up line opacity calculation, the most epxensive step for for syntheses. To use it launch Julia with more than one thread, using the -t command-line argument, or by setting the $JULIA_NUM_THREADS environment variable.