H_2^{16}O and H_2^{18}O Maser Emission from Gas-Dust Clouds

Abstract

The collisional pumping of H_2^{16}O and H_2^{18}O masers in hot dense gas-dust clouds has been simulated numerically. New data on the rate coefficients for collisional transitions from Faure et al. (2007) were used in the calculations. The possibility of detecting H_2^{18}O emission in 22.2-GHz H_2^{16}O maser sources is investigated. The medium is shown to become optically thick in the H_2^{16}O lines for which an inverted level population is observed at H_2O column densities of ~10^{19}-10^{20} cm^{-2}. A simultaneous observation of H_2^{18}O emission and H_2^{16}O maser emission in the same source will allow the physical conditions in the gas-dust cloud to be refined.

arXiv comment20 pages, 4 figures

References in corpus (5)

• Quasi-classical rate coefficient calculations for the rotational (de)excitation of H2O by H2
• Megamaser Disks in Active Galactic Nuclei
• Toward a New Geometric Distance to the Active Galaxy NGC4258: I. VLBI Monitoring of Water Maser Emission
• Sub-au imaging of water vapour clouds around four Asymptotic Giant Branch stars
• Submillimeter and Millimeter Masers

Cited by in corpus (5)

• Model of the vibrationally excited H${}_2$O maser at 658 GHz in circumstellar envelopes around asymptotic giant branch stars
• H${}_2$O Maser Pumping: The Effect of Quasi-Resonance Energy Transfer in Collisions between H${}_2$ and H${}_2$O Molecules
• H2O Maser Emission in Circumstellar Envelopes around AGB Stars: Physical Conditions in Gas-Dust Clouds
• Simulation of pumping mechanism of H2O-masers in circumstellar envelopes of late-type stars
• Collisional Pumping of H${}_2$O and CH${}_3$OH Masers in C-Type Shock Waves