2021MNRAS.506.4781M

We present the HR-PYPOPSTAR model, which provides a complete set (in ages) of high-resolution (HR) spectral energy distributions of Single Stellar Populations. The model uses the most recent high-wavelength-resolution theoretical atmosphere libraries for main-sequence, post-AGB/planetary nebulae and Wolf-Rayet stars. The spectral energy distributions are given for more than a hundred ages ranging from 0.1 Myr to 13.8 Gyr, at four different values of the metallicity (Z = 0.004, 0.008, 0.019, and 0.05), considering four different IMFs. The wavelength range goes from 91 to 24 000 Å in linear steps δλ = 0.1 Å, giving a theoretical resolving power R_ th,5000_ ∼50 000 at 5000 Å. This is the main novelty of these spectra, unique for their age and wavelength ranges. The models include the ionizing stellar populations that are relevant at both young (massive hot stars) and old (planetary nebulae) ages. We have tested the results with some examples of HR spectra recently observed with MEGARA at GTC. We highlight the importance of wavelength resolution in reproducing and interpreting the observational data from the last and forthcoming generations of astronomical instruments operating at 8-10 m class telescopes, with higher spectral resolution than their predecessors.