Spectral modelling

Spectral modelling

A meaningful comparison between observed and simulated galaxies is vital for interpreting observations and putting strong constraints on empirically motivated models adopted in simulations. To establish an accurate interface between simulations and spectral observables, we have been developing a novel, numerical methodology to provide mock spectra with nebular emission lines of galaxies via coupling spectral evolution models to cosmological simulations (e.g. IllustrisTNG) and SAMs (GAEA, SantaCruz SAM, Hirschmann+17/19/22). Specifically, nebular emission lines are computed by combining UV radiation spectra from different ionising sources (such as  young stars, AGN, post-AGB stars and shocks) with photo-ionisation codes (such as Cloudy, Ferland+13)

We trace emission lines emerging from gas elements in the ISM ionised by young stars, AGN, post-AGB stellar populations and shocks. Our predicted mock emission lines are largely consistent with those of SDSS galaxies and their location in the “BPT diagram” and successfully reproduce observed trends between strong line-ratios and Oxygen abundances in local galaxies. Currently, we are working on improving the connection between simulated ISM properties and photo-ionisation calculations and coupling our spectral evolution models to new high-resolution simulations of first galaxies.