Molecular core associated with DR 21

Journal Article · Fri Mar 01 04:00:00 EST 1985 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/162979· OSTI ID:5549214

Dickel, H R; Ho, P T.P.; Wright, M C.H.

DR 21 has been observed in the J = 1--0 line of HCN with a resolution of 12''.5 by 15''.5 using the mm-wave interferometer at the Hat Creek Observatory. The HCN line is seen in both emission and absorption as an solated clump immediately adjacent to the compact H II regions of DR 21. No other emission is seen within the 2' field of view. The full extent of the clump is about 30'' in R.A. and 60'' in decl. which corresponds to 0.3 by 0.6 pc for an assumed distance of 2 kpc. The mass of the clump is estimated to be approx.200 M/sub sun/. Two velocity components are present: the more intense one at -5 km s/sup -1/ is only seen in emission, and the other at -2.4 km s/sup -1/ is seen in emission in the northwest and mostly in absorption against the continuum source. We identify the component at -5.0 km s/sup -1/ to have higher excitation, and the one at -2.4 km s/sup -1/ to have greater column density. The blueshifted component may be either foreground material compressed by the expanding H II region, or the remnant core from which the yound stars have formed.

• Research Organization: Astronomy Department, University of Illinois
• OSTI ID: 5549214
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 290:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
COSMIC RADIO SOURCES
CYANIDES
DISTRIBUTION
EMISSION SPECTRA
ENERGY-LEVEL TRANSITIONS
EXCITATION
H2 REGIONS
HYDROCYANIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INTERFEROMETRY
INTERSTELLAR GRAINS
MAPS
PARTICLES
SPATIAL DISTRIBUTION
SPECTRA