SYnthetic MultiPhase Analysis of The Ism of Cosmic Objects – SYMPATICO

One of the ensuing astrophysical problems we are plagued by today is building a coherent picture of how the physical properties of galaxies have evolved over the history of the universe. One source of the problem is the lack of observational constraints for unresolved distant galaxies. The other is that we are we are reconstructing this history by extrapolating to earlier periods observational diagnostics established locally, sometimes with rather crude physical basis. The scenery is dramatically changing on both aspects, given the explosion of new wavelength coverage as well as spatial resolution and sensitivity. A major emphasis of current and future observatories, including Herschel, SOFIA, JWST and ALMA, as well new ground based telescopes, is delving into the physical processes controlling star formation and the subsequent (local and global) feedback of the star formation on the interstellar medium. Besides zooming into the physics and chemistry of the very local processes taking place in our Galaxy, the curtain on the stage of galaxy evolution will lift: the wide variety of star forming laboratories in our local universe present themselves for the most detailed analysis possible.
The pioneering work of IRAS, ISO and Spitzer has provided the opportunity to study the effects of star formation as a function of interstellar environment particularly through the dust properties. The infrared and sub-millimeter spectral energy distribution is the fossil footprint of a galaxy holding clues to the evolutionary history of the ISM. What obstacles do we face in going from the interpretation of the SEDs of galaxies to the physical conditions inside? Certainly the configuration and mixing of the phases of the ISM poses one of the most prominent obstacles. Tapping into the reservoir of valuable MIR to submm/mm spectroscopic signatures now becoming readily available for galaxies with Herschel, and soon, ALMA, can help to disentangle the degeneracies.
We thus propose a comprehensive study of the interaction of stars with their environment with the goal of identifying, understanding and modelling the physical processes that link the local physical conditions to the infrared and sub-millimeter emission characteristics of galaxies. To achieve this, our interdisciplinary study will be supported by 3 axes: theory, modelling and observations/interpretation. The project brings together the expertise required for the study of the chemical network taking place in the PDRs/molecular clouds as well as the photoionisation processes controlling the ionised gas phases all linked together through permanent confrontation with state-of-the art datasets.