We present the results of single dish and interferometric observations of ammonia towards 5 sources selected from a sample of H_2_O and OH masers associated with star forming regions. The Medicina telescope was used to observe the NH_3_(1,1), (2,2), and (3,3) inversion transitions. High resolution maps in the NH_3_(2,2) and (3,3) lines and in the 1.3 cm continuum were then obtained with the Very Large Array. The main result of this research is to confirm the belief that H_2_O masers form in hot dense molecular cores which are sites of massive star formation. We also find evidence for the H_2_O maser phase to be prior to the appearance of an ultracompact HII region around the embedded high mass star(s).
Codella C, Testi L, Cesaroni R (1997). The molecular environment of H_2_O masers: VLA ammonia observations. ASTRONOMY & ASTROPHYSICS, 325, 282-294.
The molecular environment of H_2_O masers: VLA ammonia observations
Testi L;
1997
Abstract
We present the results of single dish and interferometric observations of ammonia towards 5 sources selected from a sample of H_2_O and OH masers associated with star forming regions. The Medicina telescope was used to observe the NH_3_(1,1), (2,2), and (3,3) inversion transitions. High resolution maps in the NH_3_(2,2) and (3,3) lines and in the 1.3 cm continuum were then obtained with the Very Large Array. The main result of this research is to confirm the belief that H_2_O masers form in hot dense molecular cores which are sites of massive star formation. We also find evidence for the H_2_O maser phase to be prior to the appearance of an ultracompact HII region around the embedded high mass star(s).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
