AKARI Observations of the ISM in Nearby Galaxies

With AKARI, we have systematically performed near- to far-infrared (NIR-FIR) observations of the interstellar medium (ISM) in nearby galaxies as one of AKARI mission programs called ISMGN (ISM in our Galaxy and Nearby galaxies). Our scientific objective is to increase our knowledge on the properties of the ISM exposed to an extensive range of environments, the processing, evolution, and destruction of interstellar dust, and their connection with physical conditions of interstellar gas and star-forming activity. Nearby external galaxies allow us to sample a wide range of ISM physical conditions, while our Galaxy contains ideal laboratories for probing the life cycle of the ISM. We present the contents of the AKARI observations relevant to our nearby galaxy ISM studies, together with some results demonstrative of the AKARI uniqueness obtained during the AKARI cold mission phase (Phases 1&2). We have observed about 60 nearby galaxies, for many of which NIR to FIR images in the 10 photometric bands centered at the wavelengths of 3, 4, 7, 11, 15, 24, 65, 90, 140, and 160 mu m as well as 2 - 14 mu m low-resolution spectra are obtained. Our data, especially the 11 and 15 mu m imaging, the FIR 4-band imaging, and the NIR spectral data will be complementary to the Spitzer data of nearby galaxies such as those from the SINGS legacy program. We further refer to our on-going observations in the AKARI post-helium mission phase (Phase 3).