A decade-baseline study of the plasma states of ejecta knots in cassiopeia A

John Rutherford, Daniel Dewey, Enectali Figueroa-Feliciano, Sarah N.T. Heine, Fabienne A. Bastien, Kosuke Sato, C. R. Canizares

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


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.

Original languageEnglish (US)
Article number64
JournalAstrophysical Journal
Issue number1
StatePublished - May 20 2013

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'A decade-baseline study of the plasma states of ejecta knots in cassiopeia A'. Together they form a unique fingerprint.

Cite this