We present the observations of the reflection nebulae IC4954 and IC4955
region with the Infrared Camera (IRC) and the Far-Infrared Surveyor (FIS) on
board the infrared astronomical satellite AKARI during its performance
verification phase. We obtained 7 band images from 7 to 160um with higher
spatial resolution and higher sensitivities than previous observations. The
mid-infrared color of the S9W (9um) and L18W (18um) bands shows a systematic
variation around the exciting sources. The spatial variation in the
mid-infrared color suggests that the star-formation in IC4954/4955 is
progressing from south-west to north-east. The FIS data also clearly resolve
two nebulae for the first time in the far-infrared. The FIS 4-band data from
65um to 160um allow us to correctly estimate the total infrared luminosity from
the region, which is about one sixth of the energy emitted from the existing
stellar sources. Five candidates for young stellar objects have been detected
as point sources for the first time in the 11um image. They are located in the
red S9W to L18W color regions, suggesting that current star-formation has been
triggered by previous star-formation activities. A wide area map of the size of
about 1 x 1 (deg^2) around the IC4954/4955 region was created from the AKARI
mid-infrared all-sky survey data. Together with the HI 21cm data, it suggests a
large hollow structure of a degree scale, on whose edge the IC4954/4955 region
has been created, indicating star formation over three generations in largely
different spatial scales.Comment: 23 pages, 7 figures, accepted for publication in PASJ AKARI special
issu
