NEW MASER EMISSION FROM NONMETASTABLE AMMONIA IN NGC 7538. III. DETECTION OF THE (10,6) TRANSITION AND A VELOCITY GRADIENT
Ian M. Hoffman
2012
Astrophysical Journal
We present the first astronomical detection of the 14NH3 (J,K) = (10,6) line: nonthermal emission at several velocities in the Galactic star-forming region NGC 7538. Using the VLA we have imaged the (10,6) and (9,6) ammonia masers at several positions within NGC 7538 IRS 1. The individual sources have angular sizes < 0.1 arcseconds corresponding to brightness temperatures T_B > 1E6 K. We apply the pumping model of Brown & Cragg, confirming the conjecture that multiple ortho-ammonia masers can
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... cur with the same value of K. The positions and velocities of the (10,6) and (9,6) masers are modeled as motion in a possible disk or torus and are discussed in the context of recent models of the region.
doi:10.1088/0004-637x/759/1/76
fatcat:b6rj3hc7xvbqjj6qorgd3nt37e