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J. A. Ennis (Univ. of Minnesota), T. DeLaney (CfA), L. Rudnick (Univ. of Minnesota), R. Sankrit, W. P. Blair (JHU), I. M. Harrus (NASA/GSFC)
The technique of tomography on Chandra X-ray images of Kepler's supernova remnant (SNR) is used to separate the emission from circumstellar material (CSM) and the emission from ejecta. Tomography involves taking differences between images from two different energies with a scale factor chosen to accentuate features of interest. Using images made in the low-energy (0.2 to 0.65 keV), FeL+O (0.775 to 0.85 keV), and Si (1.72 to 1.96 keV) bands, two distinct X-ray populations are identified in addition to the high energy (4 to 6 keV) component. The low-energy-enhanced component has a higher low energy:FeL+O ratio than the global spectrum and highlights central knots and a thin outer northern rim. The Si-enhanced component has a higher Si:FeL+O ratio than the global spectrum and highlights the bright northern region as well as widely scattered knots which do not coincide with the low-energy-enhanced regions. Spectra of 34 regions, including two optically-selected regions and two radio-selected regions, were extracted to isolate the difference between the two tomography-identified components, and particularly to determine whether either of these components is dominated by ejecta or CSM. The tomography images were compared to known ejecta and CSM emission from radio and optical images. Much of the X-ray CSM and ejecta emission is mixed, although determining if this a physical mixture at the contact discontinuity or a superposition along the line of sight is difficult. A relation was found between non-radiative Balmer filaments and low-energy-enhanced X-ray emission. The identification of these different components will help clarify the interaction of material in young SNRs and uncover the three-dimensional structure of Kepler's SNR. This research is supported by the Space Telescope Science Institute under grant HST-GO-09731.03.
The author(s) of this abstract have provided an email address for comments about the abstract: jennis@astro.umn.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.