Chandra Observations of the Northeastern Rim of the Cygnus Loop

Abstract

We present results from spatially resolved spectral analyses of the northeastern (NE) rim of the Cygnus Loop supernova remnant (SNR) based on two Chandra observations. One pointing includes northern outermost abundance-enhanced regions discovered by recent Suzaku observations, while the other pointing is located on regions with "normal" abundances in the NE rim of the Cygnus Loop. The superior spatial resolving power of Chandra allows us to reveal that the abundance-enhanced region is concentrated in an about 200"-thickness region behind the shock front. We confirm absolute metal abundances (i.e., relative to H) as well as abundance ratios between metals are consistent with those of the solar values within a factor of about 2. Also, we find that the emission measure in the region gradually decreases toward the shock front. These features are in contrast with those of the ejecta fragments around the Vela SNR, which leads us to believe that the abundance enhancements are not likely due to metal-rich ejecta. We suggest that the origin of the plasma in this region is the interstellar medium (ISM). In the "normal" abundance regions, we confirm that abundances are depleted to the solar values by a factor of about 5 that is not expected in the ISM around the Cygnus Loop. Introduction of non-thermal emission in our model fitting can not naturally resolve the abundance-depletion problem. The origin of the depletion still remains as an open question.

arXiv comment18 pages, 6 figures

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Cited by in corpus (16)

• Supernova remnants: the X-ray perspective
• Possible Charge-Exchange X-Ray Emission in the Cygnus Loop Detected with Suzaku
• Shock Speed, Cosmic Ray Pressure, and Gas Temperature in the Cygnus Loop
• Electron-Ion Temperature Ratio in Astrophysical Shocks
• Turbulence and Energetic Particles in Radiative Shock Waves in the Cygnus Loop I: Shock Properties
• Grain Destruction in a Supernova Remnant Shock Wave
• Carbon, Helium and Proton Kinetic Temperatures in a Cygnus Loop Shock Wave
• The Ejecta Distributions of the Heavy Elements in the Cygnus Loop
• Spatially-Resolved Spectroscopy of a Balmer-Dominated Shock in the Cygnus Loop: An Extremely Thin Cosmic-Ray Precursor?
• Chandra Imaging and Spectroscopy of the Eastern XA Region of the Cygnus Loop Supernova Remnant
• X-ray Emission from Charge Exchange in the Cygnus Loop SNR
• Multiple accelerated particle populations in the Cygnus Loop with Fermi-LAT
• A Distance Estimate to the Cygnus Loop Based on the Distances to Two Stars Located Within the Remnant
• Global Far-Ultraviolet Properties of the Cygnus Loop
• The Abundance Inhomogeneity in the Northern Rim of the Cygnus Loop
• A Complete X-ray View of Supernova Remnant W28 with Einstein Probe: Spatial Distribution of Parameters and Origin of the Thermal-Composite Morphology