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Atomic carbon (CI) has been proposed to be a global tracer of the moleculargas as a substitute for CO, however, its utility remains unproven. To evaluatethe suitability of CI as the tracer, we performed [CI]$(^3P_1-^3P_0)$(hereinafter [CI](1-0)) mapping observations of the northern part of the nearbyspiral galaxy M83 with the ASTE telescope and compared the distributions of[CI](1-0) with CO lines (CO(1-0), CO(3-2), and $^{13}$CO(1-0)), HI, andinfrared (IR) emission (70, 160, and 250$ \mu$m). The [CI](1-0) distribution inthe central region is similar to that of the CO lines, whereas [CI](1-0) in thearm region is distributed outside the CO. We examined the dust temperature,$T_{\rm dust}$, and dust mass surface density, $\Sigma_{\rm dust}$, by fittingthe IR continuum-spectrum distribution with a single-temperature modifiedblackbody. The distribution of $\Sigma_{\rm dust}$ shows a much betterconsistency with the integrated intensity of CO(1-0) than with that of[CI](1-0), indicating that CO(1-0) is a good tracer of the cold molecular gas.The spatial distribution of the [CI] excitation temperature, $T_{\rm ex}$, wasexamined using the intensity ratio of the two [CI] transitions. An appropriate$T_{\rm ex}$ at the central, bar, arm, and inter-arm regions yields a constant[C]/[H$_2$] abundance ratio of $\sim7 \times 10^{-5}$ within a range of 0.1 dexin all regions. We successfully detected weak [CI](1-0) emission, even in theinter-arm region, in addition to the central, arm, and bar regions, usingspectral stacking analysis. The stacked intensity of [CI](1-0) is found to bestrongly correlated with $T_{\rm dust}$. Our results indicate that the atomiccarbon is a photodissociation product of CO, and consequently, compared toCO(1-0), [CI](1-0) is less reliable in tracing the bulk of "cold" molecular gasin the galactic disk.

Atomic Carbon [CI]$(^3P_1-^3P_0)$ Mapping of the Nearby Galaxy M83