A DECADE-BASELINE STUDY OF THE PLASMA STATES OF EJECTA KNOTS IN CASSIOPEIA A
Author(s)
Dewey, Dan; Figueroa-Feliciano, Enectali; Bastien, Fabienne A.; Sato, Kosuke; Rutherford, John Morton; Heine, Sarah Nicole Trowbridge; Canizares, Claude R.; ... Show more Show less
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We present the analysis of 21 bright X-ray knots in the Cassiopeia A supernova remnant from observations spanning 10 yr. We performed a comprehensive set of measurements to reveal the kinematic and thermal state of the plasma in each knot, using a combined analysis of two high energy resolution High Energy Transmission Grating (HETG) and four medium energy resolution Advanced CCD Imaging Spectrometer (ACIS) sets of spectra. The ACIS electron temperature estimates agree with the HETG-derived values for approximately half of the knots studied, yielding one of the first comparisons between high resolution temperature estimates and ACIS-derived temperatures. We did not observe the expected spectral evolution—predicted from the ionization age and density estimates for each knot—in all but three of the knots studied. The incompatibility of these measurements with our assumptions has led us to propose a dissociated ejecta model, with the metals unmixed inside the knots, which could place strong constraints on supernova mixing models.
Date issued
2013-05Department
Massachusetts Institute of Technology. Department of Physics; MIT Kavli Institute for Astrophysics and Space ResearchJournal
The Astrophysical Journal
Publisher
IOP Publishing
Citation
Rutherford, John, Daniel Dewey, Enectali Figueroa-Feliciano, Sarah N. T. Heine, Fabienne A. Bastien, Kosuke Sato, and C. R. Canizares. “A DECADE-BASELINE STUDY OF THE PLASMA STATES OF EJECTA KNOTS IN CASSIOPEIA A.” The Astrophysical Journal 769, no. 1 (May 20, 2013): 64.
Version: Author's final manuscript
ISSN
0004-637X
1538-4357