On Surface Brightness and Flux Calibration for Point and Compact
  Extended Sources in the AKARI Far-IR All-Sky Survey (AFASS) Maps
  The AKARI Infrared Astronomical Satellite produced the all-sky survey (AFASS)
maps in the far-IR at roughly arc-minute spatial resolution, enabling us to
investigate the whole sky in the far-IR for objects having surface brightnesses
greater than a few to a couple of dozen MJy/sr. While the AFASS maps are
absolutely calibrated against large-scale diffuse emission, it was uncertain
whether or not an additional flux correction for point sources was necessary.
Here, we verify that calibration for point-source photometry in the AFASS maps
is proper. With the aperture correction method based on the empirical
point-spread-function templates derived directly from the AFASS maps, fluxes in
the AKARI bright source catalogue (BSC) are reproduced. The AKARI BSC fluxes
are also satisfactorily recovered with the 1 sigma aperture, which is the
empirical equivalent of an infinite aperture. These results confirm that in the
AFASS maps far-IR photometry can be properly performed by using the aperture
correction method for point sources and by summing all pixel values within an
appropriately defined aperture of the intended target (i.e., the aperture
photometry method) for extended sources.
