Summary of the Meeting

Abstract

This symposium has shown that the field of astrophysical PAHs remains extremely activeand lively. Thanks to Spitzer Space Telescope, the number of PAH papershas spectacularly increased, including now up to the young Universe. Laboratory andtheoretical works have progressed in proportion. Salient features of the six sessions ofthe symposium are briefly reviewed. Comprehensive analyses of the rich and complexinfrared spectra of interstellar PAHs are now well established, based on a large databaseof observational data. PAHs are fully confirmed as excellent tracers of star formation,but their emission strongly depends on metallicity. Various observations, especially inharsh environments, have confirmed the complexity of the lifecycle of PAHs in space, andthe need for multiple formation modes. Electronic properties remain a major issue forastronomical PAHs, including their possible connection with the diffuse interstellarbands, and the possible importance of protonated PAHs. Progress in studying complexcarbonaceous compounds, such as those of various soots, and in synthesizing very largePAHs may give important clues for understanding interstellar PAHs. Significant progresswas also reported in modeling the important role of PAHs in the physics and chemistry ofthe interstellar medium.