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We probe the column densities and masses traced by the ionized and neutralatomic carbon with spectrally resolved maps, and compare them to the diffuseand dense molecular gas traced by [C I] and low-$J$ CO lines toward thestar-forming region M17SW. We mapped a 4.1pc x 4.7pc region in the [C I] 609m$\mu$ line using the APEX telescope, as well as the CO isotopologues with theIRAM 30m telescope. We analyze the data based on velocity channel maps that are1 km/s wide. We correlate their spatial distribution with that of the [C II]map obtained with SOFIA/GREAT. Optically thin approximations were used toestimate the column densities of [C I] and [C II] in each velocity channel. Thespatial distribution of the [C I] and all CO isotopologues emission was foundto be associated with that of [C II] in about 20%-80% of the mapped region,with the high correlation found in the central (15-23 km/s ) velocity channels.The excitation temperature of [C I] ranges between 40 K and 100 K in the innermolecular region of M17 SW. Column densities in 1 km/s channels between~10$^{15}$ and ~10$^{17}$ cm$^{-2}$ were found for [C I]. Just ~20% of thevelocity range (~40 km/s) that the [C II] line spans is associated with thestar-forming material traced by [C I] and CO. The total gas mass estimated fromthe [C II] emission gives a lower limit of ~4.4x10$^3$ $M_{\odot}$. At least64% of this mass is not associated with the star-forming material in M17SW. Wealso found that about 36%, 17%, and 47% of the [C II] emission is associatedwith the HII, HI, and H_2 regimes, respectively. Comparisons with theH41$\alpha$ line shows an ionization region mixed with the neutral and part ofthe molecular gas, in agreement with the clumped structure and dynamicalprocesses at play in M17SW. These results are also relevant to extra-galacticstudies in which [C II] is often used as a tracer of star-forming material.

Detection of a large fraction of atomic gas not associated with star-forming material in M17 SW