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Abstract: We observed an area of 10 deg^2 of the Large Magellanic Cloud using theInfrared Camera on board AKARI. The observations were carried out using fiveimaging filters 3, 7, 11, 15, and 24 micron and a dispersion prism 2 - 5micron, $\lambda - \Delta\lambda$ $\sim$ 20 equipped in the IRC. This paperdescribes the outline of our survey project and presents some initial resultsusing the imaging data that detected over 5.9x10^5 near-infrared and 6.4x10^4mid-infrared point sources. The 10 $\sigma$ detection limits of our survey areabout 16.5, 14.0, 12.3, 10.8, and 9.2 in Vega-magnitude at 3, 7, 11, 15, and 24micron, respectively. The 11 and 15 micron data, which are unique to AKARI IRC,allow us to construct color-magnitude diagrams that are useful to identifystars with circumstellar dust. We found a new sequence in the color-magnitudediagram, which is attributed to red giants with luminosity fainter than that ofthe tip of the first red giant branch. We suggest that this sequence is likelyto be related to the broad emission feature of aluminium oxide at 11.5 micron.The 11 and 15 micron data also indicate that the 11 - 15 micron color ofboth oxygen-rich and carbon-rich red giants once becomes blue and then turnsred again in the course of their evolution, probably due to the change in theflux ratio of the silicate or silicon carbide emission feature at 10 or 11.3micron to the 15 micron flux.

Author: Yoshifusa Ita 1, Takashi Onaka 2, Daisuke Kato 2, Toshihiko Tanabe 3, Itsuki Sakon 2, Hidehiro Kaneda 4, Akiko Kawamura 5, Takash

Source: https://arxiv.org/


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