Assuming LTE, we synthesise solar G band spectra from the semiempirical flux-tube model of Briand Solanki (1995). The results agree with observed G-band bright-point contrasts within the uncertainty set by the amount of scattered light. We find that it is the weakening of spectral lines within the flux tube that makes the bright-point contrast in the G band exceed the continuum contrast. We also synthesise flux-tube spectra assuming LTE for the full wavelength range from UV to IR, and identify other promising passbands for flux-tube observations.

GALEV evolutionary synthesis models describe the evolution of stellar populations in general, of star clusters as well as of galaxies, both in terms of resolved stellar populations and of integrated light properties over cosmological timescales of > 13 Gyr from the onset of star formation shortly after the Big Bang until today. For galaxies, GALEV includes a simultaneous treatment of the chemical evolution of the gas and the spectral evolution of the stellar content, allowing for what we call a chemically consistent treatment: We use input physics (stellar evolutionary tracks, stellar yields and model atmospheres) for a large range of metallicities and consistently account for the increasing initial abundances of successive stellar generations. Here we present the latest version of the galev evolutionary synthesis models that are now interactively available at this http URL. We review the currently used input physics, and also give details on how this physics is implemented in practice. We explain how to use the interactive web-interface to generate models for user-defined parameters and also give a range of applications that can be studied using GALEV, ranging from star clusters, undisturbed galaxies of various types E ... Sd to starburst and dwarf galaxies, both in the local and the high-redshift universe.