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 (43)

• Physical Properties of Wolf-Rayet Stars
• Scattering by Interstellar Dust Grains: Optical and Ultraviolet
• The Universality of Turbulence in Galactic Molecular Clouds
• The SMART Data Analysis Package for the Infrared Spectrograph on the Spitzer Space Telescope
• On the magnetic fields and particle acceleration in Cas A
• 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
• Polarization Observations of 1720 MHz OH Masers toward the Three Supernova Remnants W28, W44, and IC443
• A Chandra X-ray Survey of Ejecta in the Cassiopeia A Supernova Remnant
• The Expansion Center and Dynamical Age of the Galactic Supernova Remnant Cassiopeia A
• Constraints on the Progenitor of Cassiopeia A
• On the Determination of Ejecta Structure and Explosion Asymmetry from the X-ray Knots of Cassiopeia A
• The Three-Dimensional Structure of Cassiopeia A
• Shocked Molecular Gas in the Supernova Remnants W 28 and W 44: Near-infrared and millimeter-wave observations
• Newly Synthesized Elements and Pristine Dust in the Cassiopeia A Supernova Remnant
• OH(1720 MHz) Masers As Signposts of Molecular Shocks
• No cold dust within the supernova remnant Cassiopeia A
• Radio Spectral Index Variations and Physical conditions in Kepler's Supernova Remnant
• Excitation and Disruption of a Giant Molecular Cloud by the Supernova Remnant 3C391
• XMM-Newton observations of the supernova remnant IC 443: II. evidence of stellar ejecta in the inner regions
• Hubble Space Telescope WFPC-2 Imaging of Cassiopeia A
• Spitzer Spectral Mapping of Supernova Remnant Cassiopeia A
• Interstellar and Ejecta Dust in the Cas A Supernova Remnant
• Spitzer IRAC Images and Sample Spectra of Cassiopeia A's Explosion
• Discovery of Outlying, High-Velocity Oxygen-Rich Ejecta in Cassiopeia A
• A Comparison of X-ray and Radio Emission from the Supernova Remnant Cassiopeia A
• Radio Emission from a Young Supernova Remnant Interacting with an Interstellar Cloud: MHD Simulation with Relativistic Electrons
• X-ray observation of the shocked red supergiant wind of Cassiopeia A
• GBT Observations of IC 443: the Nature of OH(1720 MHz) Masers and OH Absorption
• Ejecta Knot Flickering, Mass Ablation, and Fragmentation in Cassiopeia A
• Infrared Echoes Reveal the Shock Breakout of the Cas A Supernova
• Shocked Molecular Gas in the Supernova Remnant HB 21
• The OH (1720 MHz) Supernova Remnant Masers in W44: MERLIN and VLBA Polarization Observations
• Spectroscopic detection of Carbon Monoxide in the Young Supernova Remnant Cassiopeia A
• Near-Infrared Synchrotron Emission from Cas A
• Carbon Monoxide in the Cassiopeia A Supernova Remnant
• Star Formation Associated With the SNR IC443
• CO rotational line emission from a dense knot in Cas A Evidence for active post-reverse-shock chemistry
• Nucleosynthetic Layers in the Shocked Ejecta of Cassiopeia A
• Origin of gamma-ray emission in the shell of Cassiopeia A
• Supernova progenitor stars in the initial range of 23 to 33 solar masses and their relation with the SNR Cas A
• Evidence for Proportionate Partition Between the Magnetic Field and Hot Gas in Turbulent Cassiopeia A

Cited by in corpus (21)

• Radio emission from Supernova Remnants
• The dust mass in Cassiopeia A from a spatially resolved Herschel analysis
• A Systematic Survey for Broadened CO Emission Toward Galactic Supernova Remnants
• X-ray Measurements of the Particle Acceleration Properties at Inward Shocks in Cassiopeia A
• An HST Survey of the Highest-Velocity Ejecta in Cassiopeia A
• Evidence for past interaction with an asymmetric circumstellar shell in the young SNR Cassiopeia A
• Carbon and hydrogen radio recombination lines from the cold clouds towards Cassiopeia A
• Molecular gas toward supernova remnant Cassiopeia A
• The dust mass in Cassiopeia A from infrared and optical line flux differences
• A Deep Near-Infrared [Fe II]+[Si I] Emission Line Image of the Supernova Remnant Cassiopeia A
• The Temperature and Ionization of Unshocked Ejecta in Cas 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
• Mapping low frequency carbon radio recombination lines towards Cassiopeia A at 340, 148, 54 and 43 MHz
• 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
• Gamma-ray Emission of the Kes 73/1E 1841-045 Region Observed with the Fermi Large Area Telescope
• A High Resolution Study of Carbon Radio Recombination Lines towards Cassiopeia A
• Molecular Clouds Associated with {H \small{II}} regions and Candidates within l = 106.65${}^{\circ }$ to 109.50${}^{\circ }$ and b = $-$1.85${}^{\circ }$ to 0.95${}^{\circ }$
• A Study of Radio Knots within Supernova Remnant Cassiopeia A
• A 95 GHz Methanol Emission Survey Toward Eight Small Supernova Remnants
• The forward and reverse shock dynamics of Cassiopeia A