Interaction between cassiopeia a and nearby molecular clouds

C. D. Kilpatrick, J. H. Bieging, G. H. Rieke

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


We present spectroscopy of the supernova remnant Cassiopeia A (Cas A) observed at infrared wavelengths from 10 to 40 μm with the Spitzer Space Telescope and at millimeter wavelengths in 12CO and 13CO J =2-1 (230 and 220 GHz) with the Heinrich Hertz Submillimeter Telescope. The IR spectra demonstrate high-velocity features toward a molecular cloud coincident with a region of bright radio continuum emission along the northern shock front of Cas A. The millimeter observations indicate that CO emission is broadened by a factor of two in some clouds toward Cas A, particularly to the south and west. We believe that these features trace interactions between the Cas A shock front and nearby molecular clouds. In addition, some of the molecular clouds that exhibit broadening in CO lie 1′-2′ away from the furthest extent of the supernova remnant shock front. We propose that this material may be accelerated by ejecta with velocity significantly larger than the observed free-expansion velocity of the Cas A shock front. These observations may trace cloud interactions with fast-moving outflows such as the bipolar outflow along the southwest to northeast axis of the Cas A supernova remnant, as well as fast-moving knots seen emerging in other directions.

Original languageEnglish (US)
Article number144
JournalAstrophysical Journal
Issue number2
StatePublished - Dec 1 2014


  • ISM: individual objects (Cassiopeia A)
  • ISM: molecules
  • ISM: supernova remnants
  • Infrared: ISM
  • Shock waves

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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