AKARI infrared observations of edge-on spiral galaxy NGC 3079
  We present AKARI near- to far-infrared images of the nearby edge-on spiral
galaxy NGC 3079 in 10 photometric bands. The spectral energy distribution
consists of continuum emission from dust with a single temperature of 28-33 K
together with strong mid-infrared emission features from polycyclic aromatic
hydrocarbons (PAHs). We derive the dust masses of 5.6x10^6 M_sun and 1.4x10^7
M_sun for the central 4 kpc region and the whole galaxy, respectively, and find
that a gas-to-dust mass ratio is unusually high in the central region (\sim
1100) and even for the whole galaxy (\sim 860). The ratio of the surface
brightness distribution at the wavelength of 7 um to that at 11 um suggests
that the properties of PAHs have spatial variations. Emission from ionized and
neutral PAHs is relatively strong in the center and the disk regions,
respectively, suggesting stronger radiation field and thus relatively active
star formation in the center. Yet the total infrared luminosities of the galaxy
indicate rather low star formation rates. These results suggest that NGC 3079
is in an early-phase starburst stage.
