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تسجيل مستخدم جديدThe Central Regions of M31 in the 3 - 5 micron Wavelength Region
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Images obtained with NIRI on the Gemini North telescope are used to investigate the photometric properties of the central regions of M31 in the 3 - 5 micron wavelength range. The light distribution in the central arcsecond differs from what is seen in the near-infrared in the sense that the difference in peak brigh tness between P1 and P2 is larger in M than in K; no obvious signature of P3 is dete cted in M. These results can be explained if there is a source of emission that contributes ~ 20% of the peak M light of P1 and has an effective temperature of no more than a few hundred K that is located between P1 and P2. Based on the red K-M color of this source, it is suggested that the emission originates in a circumstellar dust shell surrounding a single bright AGB star. A similar bright source that is ~ 8 arcsec from the center of the galaxy is also detected in M. Finally, the (L, K-L) color-magnitude diagram of unblended stars shows a domin ant AGB population with photometric characteristics that are similar to those of the most luminous M giants in the Galactic bulge.
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