SIMBAD references

2012ApJ...759...76H - Astrophys. J., 759, 76 (2012/November-1)

New maser emission from nonmetastable ammonia in NGC 7538. III. Detection of the (10,6) transition and a velocity gradient.


Abstract (from CDS):

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 Very Large Array 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 arcsec corresponding to brightness temperatures TB ≳ 106 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.

Abstract Copyright:

Journal keyword(s): HII regions - ISM: individual: NGC 7538 - ISM: molecules - masers - radio continuum: ISM

Simbad objects: 11

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