Interaction between Cassiopeia A and Nearby Molecular Clouds

Abstract

We present spectroscopy of the supernova remnant Cassiopeia A (Cas A) observed at infrared wavelengths from 10 - 40 micron 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.

17 pages, 17 figures, published in ApJ

References in corpus (11)

• Physical Properties of Wolf-Rayet Stars
• The Cassiopeia A Supernova was of Type IIB
• Freshly Formed Dust in the Cassiopeia A Supernova Remnant as Revealed by the Spitzer Space Telescope
• Spectral Mapping Reconstruction of Extended Sources
• No cold dust within the supernova remnant Cassiopeia A
• XMM-Newton observations of the supernova remnant IC 443: II. evidence of stellar ejecta in the inner regions
• Interstellar and Ejecta Dust in the Cas A Supernova Remnant
• Spitzer IRAC Images and Sample Spectra of Cassiopeia A's Explosion
• GBT Observations of IC 443: the Nature of OH(1720 MHz) Masers and OH Absorption
• Infrared Echoes Reveal the Shock Breakout of the Cas A Supernova
• Carbon Monoxide in the Cassiopeia A Supernova Remnant

Cited by in corpus (8)

• The dust mass in Cassiopeia A from a spatially resolved Herschel analysis
• Carbon and hydrogen radio recombination lines from the cold clouds towards Cassiopeia A
• Molecular Environments of Three Large Supernova Remnants in the Third Galactic Quadrant: G205.5+0.5, G206.9+2.3, and G213.0-0.6
• Discovery of Broad Molecular lines and of Shocked Molecular Hydrogen from the Supernova Remnant G357.7+0.3: HHSMT, APEX, Spitzer and SOFIA Observations
• A Large-field J=1-0 Survey of CO and Its Isotopologues Toward the Cassiopeia A Supernova Remnant
• A High Resolution Study of Carbon Radio Recombination Lines towards Cassiopeia A
• Gamma-ray Emission of the Kes 73/1E 1841-045 Region Observed with the Fermi Large Area Telescope
• A 95 GHz Methanol Emission Survey Toward Eight Small Supernova Remnants