AAS 197, January 2001
Session 63. Gamma Ray Sources, Supernovae and Supernova Remnants
Oral, Tuesday, January 9, 2001, 1:30-3:00pm, Town and Country

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[63.04] Nonthermal X-ray Emission in Supernova Remnants

K.K. Dyer, S.P. Reynolds, K.J. Borkowski (NCSU), R. Petre (NASA's GSFC)

While synchrotron emission in supernova remnants has been observed and analyzed to great effect at radio wavelengths, there is a growing number of both galactic and extragalactic supernova remnants with nonthermal (non-plerionic) emission in the X-ray band. In the past the only tool available to describe X-ray synchrotron emission was the generic powerlaw model. Powerlaw models are inadequate for several reasons: simple comparison of radio and X-ray fluxes show that synchrotron must drop significantly below the radio-measured powerlaw somewhere before X-ray energies. Powerlaw models are also very poorly constrained. Coupled with a complex thermal model there is often no unique solution for the thermal-nonthermal separation. I will present synchrotron models, which use the radio spectral index and flux as inputs and include the full single-particle emissivity. Our models of synchrotron emission can account for the spectra of dominantly nonthermal supernova remnants with interesting consequences for residual thermal abundances and acceleration of particles. In addition, these models, which use the radio spectral index and flux as inputs, deliver a much better-constrained separation between the thermal and nonthermal components. These models make both spectral and spatial predictions, describing how the nonthermal emission varies across the remnant. We have demonstrated that the integrated spectrum of SN1006, a remnant dominated by nonthermal emission, is well described by synchrotron models. As an example of the use of thermal and nonthermal models I will present spatially resolved observations of this remnant, analyzed with versions of the synchrotron model designed to describe the remnant subregions. Armed with spatially resolved nonthermal models and new thermal models we now have the tools to separate thermal and nonthermal X-rays in supernova remnants. The ability to separate thermal and nonthermal emission is essential to understanding the thermal component, as well as having implications for nonthermal emission. This work is supported by the Graduate Student Researchers Program through NASA's GSFC.

If you would like more information about this abstract, please follow the link to http://wonka.physics.ncsu.edu/~kkdyer. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: kkdyer@unity.ncsu.edu

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