NEW MASER EMISSION FROM NONMETASTABLE AMMONIA IN NGC 7538. III. DETECTION OF THE (10,6) TRANSITION AND A VELOCITY GRADIENT

Journal Article · Thu Nov 01 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/759/1/76· OSTI ID:22086455

We present the first astronomical detection of the {sup 14}NH{sub 3} (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 {approx}< 0.1 arcsec corresponding to brightness temperatures T{sub B} {approx}> 10{sup 6} K. We apply the pumping model of Brown and 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.

• OSTI ID: 22086455
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 759; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AMMONIA
ASTROPHYSICS
BRIGHTNESS
DETECTION
GALAXY CLUSTERS
H2 REGIONS
MASERS
MOLECULES
NITROGEN 14
PHOTON EMISSION
PUMPING
RADIOASTRONOMY
STARS
VELOCITY