| Abstract
| - Images of ${\it JHK}$ and ${\it gi}$ obtained with the Canada-France-Hawaii Telescope are used to investigate the stellar contents of the resolved asymptotic giant branch (AGB) population in the area of $3\farcm6\times6\farcm3$ on the central bar of the dwarf irregular galaxy NGC 6822. The upper envelope of near-infrared $(J-K,K)$ and $(H-K,K)$ color-magnitude diagrams (CMDs) shows four components of main-sequence stars, foreground stars, massive supergiants, and AGB stars. These components are also noticeable in the bright part of $(g-i,g)$ CMD. We select AGB stars in NGC 6822 from the $(g-K,g)$ CMD, which has a long spectral wavelength base line in the color index. There are 141 C stars with a mean absolute magnitude of $\langle M_{K}\rangle=-7.60\pm0.50$, and with mean colors of $\langle (J-K)_{0}\rangle=1.77\pm0.41$, and $\langle (H-K)_{0}\rangle=0.75\pm0.28$. The number ratio of C stars to M-giants (C/M) is estimated as $0.27\pm0.03$, while the northern part of the bar has a somewhat lower C/M ratio than the southern part. The $(J-K)$ and $(H-K)$ color distributions of AGB stars contain a main peak of M-giant stars and a red tail of C stars. The broad color distributions for M-giants indicate that NGC 6822 has a wide range of intermediate ages with a peak at log $(t_{\rm yr})\sim9.0$. The MK luminosity function (LF) for C stars in the central bar of NGC 6822 is likely to be a Gaussian distribution, while the LF of C stars in the southern part is slightly skewed to the brighter side than in northern part. The mean bolometric magnitude of 141 C stars in NGC 6822 is $\langle M_{\rm bol}\rangle=-4.36\pm0.54$. The bolometric LF for M-giants extends up to $M_{\rm bol}=-6.5$, while the one for C stars spans $-5.8<M_{\rm bol}<-3.5$.
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