Interaction between the Sumpernova Remnant CTB 80 and the
Ambient Interstellar Medium: H I and CO Observations
B.-C. Koo, M. S. Yun, P. T. P. Ho, Y. Lee, R. L. Snell
Astrophysical Journal, V.417, p.196 (1993)
Abstract
We performed VLA H I 21 cm line and 12CO J = 1-0 line observations of
the old supernova remnant (SNR) CTB 80. The clumpy structure of the
fast, Vexp = 72 km/s, expanding SNR shell detected by Koo et al. (1990)
is found to be due to fast-moving H I clumps, which have a dense,
n(H) = 100 cm^-3, core surrounded by a relatively diffuse envelope.
These clumps are most likely the pre-existing "cold clouds" in the
ambient interstellar medium (ISM) that had been swept-up and accelerated
by the SN blast wave. CO observations what that most of the molecular
gas in this region is confined into two large filamentary clouds.
There is no certain evidence for the interaction between the SNR and
the molecular cloud. By analyzing the Arecibo H I data of Koo et al.,
we found that the ISM around CTB 80 is far from being uniform and
homogeneous. Instead, it seems to be composed of a large cold cloud,
a warm neutral medium pervaded by small cold clouds, and a tenuous
hot tunnel, which is close to the McKee & Ostriker's three-phase
ISM model. We discuss how the ambient ISM shaped the morphology of
CTB 80 in H I, infrared, and radio continuum.