AKARI IRC Survey of the Large Magellanic Cloud: Outline of the Survey and Initial Results

作者：Ita Yoshifusa^*; Onaka Takashi; Kato Daisuke; Tanabe Toshihiko; Sakon Itsuki; Kaneda Hidehiro; Kawamura Akiko; Shimonishi Takashi; Wada Takehiko; Usui Fumihiko; Koo Bon Chul; Matsuura Mikako; Takahashi Hidenori; Nakada Yoshikazu; Hasegawa Tetsuo; Tamura Motohide

来源：Publications of the Astronomical Society of Japan, 2008, 60: S435-S451.

• galaxies: Magellanic Clouds
• infrared: stars
• ISM: supernova remnants
• stars: AGB and post-AGB-young stellar objects

We observed an area of 10 deg(2) of the Large Magellanic Cloud using the Infrared Camera (IRC) on board AKARI. The observations were carried out using five imaging filters (3, 7, 11, 15, and 24 mu m) and a dispersion prism (2-5 mu m, lambda/Delta lambda similar to 20) equipped in the IRC. This paper describes an outline of our survey project, and presents some initial results using imaging data that detected over 5.9 x 10(5) near-infrared and 6.4 x 10(4) mid-infrared point sources. The 10 sigma detection limits of our survey are about 16.5, 14.0, 12.3, 10.8, and 9.2 in Vega-magnitude at 3, 7, 11, 15, and 24 mu m, respectively. The 11 and 15 Am data, which are unique to AKARI IRC, allow us to construct color-magnitude diagrams that are useful to identify stars with circumstellar dust. We found a new sequence in the color-magnitude diagram, which is attributed to red giants with luminosity fainter than that of the tip of the first red-giant branch. We suggest that this sequence is likely to be related to the broad emission feature of aluminum oxide at 11.5 mu m. The 11 and 15 mu m data also indicate that the ([11]-[15]) color of both oxygen-rich and carbon-rich red giants once becomes blue, and then turns red again in the course of their evolution, probably due to a change in the flux ratio of the silicate or silicon carbide emission feature at 10 or 11.3 mu m to the 15 mu m flux.

• 出版日期2008
• 单位中国科学院国家天文台