Physical Sciences and Mathematics Commons^™

Water Absorption From Line-Of-Sight Clouds Toward W49a, R Plume, Mj Kaufman, Da Neufeld, Ronald L. Snell, Dj Hollenbach, Pf Goldsmith, J Howe, Ea Bergin, Gj Melnick, F Bensch

Astronomy Department Faculty Publication Series

We have observed six clouds along the line of sight toward W49A using the Submillimeter Wave Astronomy Satellite and several ground-based observatories. The ortho-H₂O 1₁₀ → 1₀₁ and OH (1665 and 1667 MHz) transitions are observed in absorption, whereas the low-J CO, ¹³CO, and C¹⁸O lines, as well as the [C I] ³P₁-³P₀ transition, are seen in emission. The emission lines allow us to determine the gas density (n ~ 1500-3000 cm^-3) and CO column densities [N(CO) ~ 7.9 …