New Maser Emission from Nonmetastable Ammonia in NGC 7538. III. Detection of the (10,6) Transition and a Velocity Gradient

Autor:	Hoffman, Ian M.
Rok vydání:	2012
Předmět:	Astrophysics - Astrophysics of Galaxies Astrophysics - Solar and Stellar Astrophysics
Druh dokumentu:	Working Paper
DOI:	10.1088/0004-637X/759/1/76
Popis:	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 occur 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. Comment: 6 pages, 5 figures, 1 table; emulateapj, accepted to ApJ; color figures only on arXiv
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/1209.5365 Zobrazit plný text záznamu View this record from Arxiv