High-Resolution Panchromatic Spectral Models of Galaxies including Photoionisation and Dust

An updated version of the dust radiation transfer code sunrise, including mod-els for star-forming regions and a self-consistent calculation of the spatially de-pendent dust and PAH emission, is presented. Given a hydrodynamic simula-tion of a galaxy, this model can calculate a realistic 2-dimensional ultraviolet– submillimeter spectral energy distribution of the galaxy, including emission lines from H ii regions, from any viewpoint. To model the emission from star-forming regions, the mappingsiii photoionization code is used. The high wavelength reso-lution ( ∼ 1000 wavelengths) is made possible by the polychromatic Monte-Carlo algorithm employed by sunrise. From the 2-D spectral energy distributions, im-ages in any filter bands or integrated galaxy SEDs can be created. Using a suite of hydrodynamic simulations of disc galaxies, the output broad-band images and spectral energy distributions are compared with observed galaxies from the multiwavelength SINGS and SLUGS galaxy surveys. Overall, the output spec-tral energy distributions show a good match with observed galaxies in colours ranging from GALEX far-UV to SCUBA submillimeter wavelengths. The only possible exception is the 160µm/850µm colour, which the simulations underes-timate by a factor ∼ 5 compared to the SINGS sample. However, the simulations here agree with the SLUGS galaxies, which consistently have significantly larger amounts of cold dust than the SINGS galaxies. The sunrise model can be used to generate simulated observations of arbitrary hydrodynamic galaxy simula-tions. In this way, predictions of galaxy formation theories can be directly tested against observations of galaxies. Key words: radiative transfer – methods: numerical – dust, extinction – galax-ies: spiral, ultraviolet: galaxies – infrared: galaxies.