Published November 15, 1981
| Version v1
Journal article
VLA observations of DR 21 NH3 (1,1) absorption: direct evidence for clumping
- 1. U. S. Naval Observatory, Washington, D. C.
Description
The (1,1) transition of NH3 was observed in absorption against DR 21 with a synthesized beam of 2'' size at the VLA. The DR 21 continuum is resolved by the VLA into components distributed within a range of about 30'', but only the brightest (and most southerly) component is absorbed by NH3. The indicated filling factor and optical depth of the absorption feature are consistent with a model suggested by emission results, ammonia existing in optically thick thermalized clumps. One of these would be producing the observed absorption
Additional details
Publishing Information
- Journal Title
- Astrophys. J., Lett. Ed.
- Journal Volume
- 250
- Journal Issue
- 2
- Series
- Astrophys. J., Lett. Ed.
- Journal Page Range
- L85-L89
- ISSN
- 0571-7248
INIS
- Country of Publication
- United States
- Country of Input or Organization
- United States
- INIS RN
- 14744410
- Subject category
- S79: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;
- Descriptors DEI
- ABSORPTION; AMMONIA; ENERGY LEVELS; ENERGY-LEVEL TRANSITIONS; H2 REGIONS; INTERFEROMETRY; INTERSTELLAR SPACE
- Descriptors DEC
- COSMIC RADIO SOURCES; HYDRIDES; HYDROGEN COMPOUNDS; NITROGEN COMPOUNDS; NITROGEN HYDRIDES; SPACE