AKARI Far-Infrared All-Sky Survey Maps
  Far-infrared observations provide crucial data for the investigation and
characterisation of the properties of dusty material in the Interstellar Medium
(ISM), since most of its energy is emitted between ~100 and 200 um. We present
the first all-sky image from a sensitive all-sky survey using the Japanese
AKARI satellite, in the wavelength range 50 -- 180 um. Covering >99% of the sky
in four photometric bands with four filters centred at 65 um, 90 um, 140 um,
and 160 um wavelengths, this achieved spatial resolutions from 1 to 2 arcmin
and a detection limit of <10 MJy sr-1, with absolute and relative photometric
accuracies of <20%. All-sky images of the Galactic dust continuum emission
enable astronomers to map the large-scale distribution of the diffuse ISM
cirrus, to study its thermal dust temperature, emissivity and column density,
and to measure the interaction of the Galactic radiation field and embedded
objects with the surrounding ISM. In addition to the point source population of
stars, protostars, star-forming regions, and galaxies, the high Galactic
latitude sky is shown to be covered with a diffuse filamentary-web of dusty
emission that traces the potential sites of high latitude star formation. We
show that the temperature of dust particles in thermal equilibrium with the
ambient interstellar radiation field can be estimated by using 90 um, 140 um,
and 160 um data. The FIR AKARI full-sky maps provide a rich new data set within
which astronomers can investigate the distribution of interstellar matter
throughout our Galaxy, and beyond.
