The AKARI mid-infrared all-sky survey: Development of a new inter-planetary dust map and the world's first all-sky PAH map

We are constructing accurately calibrated 9 μm and 18 μm all-sky diffuse maps from the AKARI mid-infrared all-sky survey data. These maps are heavily affected by the foreground emission of the zodiacal light, which has an intensity peak at around these wavelengths. We carefully separate the zodiacal emission component from the maps using Kelsall's model. Through improvement of the parameters in the zodiacal light emission model, we obtained new insight on the structure and composition of the interplanetary dust in our solar system. The zodiacal light removed AKARI 9 μpm map is the world's first all-sky PAH map, that traces the emission features of Galactic polycyclic aromatic hydrocarbons (PAHs) at wavelengths of 6.2, 7.7, 8.6, and 11.3 μm. On a global scale, PAHs show good spatial correlation with tracers of general ISM such as CO, HI, and far-IR dust emissions. On a local scale, we recognize the variation of physical state and compositions of hydrocarbons reflecting the variation of the local physical environment. This PAH map will be effectively used in diagnoses of various interstellar phenomena.