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Hard X-ray Emission from Cassiopeia A SNR

L. -S. The·M. D. Leising·D. H. Hartmann·J. D. Kurfess·P. Blanco·D. Bhattacharya
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Abstract

We report the results of extracting the hard X-ray continuum spectrum of Cas A SNR from RXTE/PCA Target of Opportunity (TOO) observations and CGRO/OSSE observations. The data can rule out the single thermal bremsstrahlung model for Cas A continuum between 2 and 150 keV. The single power law model gives a mediocre fit (~5%) to the data with a power-law index, $Γ$ = 2.94$\pm$0.02. A model with two component (bremsstrahlung + bremsstrahlung or bremsstrahlung + power law) gives a good fit. The power law index is quite constrained suggesting that this continuum might not be the X-ray thermal bremmstrahlung from accelerated MeV electrons at shock fronts (Asvarov et al. 1989) which would have $Γ\simeq$2.26. With several SNRs detected by ASCA showing a hard power-law nonthermal X-ray continuum, we expect a similar situation for Cas A SNR which has $Γ$=2.98$\pm$0.09. We discuss the implication of the hardest nonthermal X-rays detected from Cas A to the synchrotron radiation model.

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L. -S. The, M. D. Leising, D. H. Hartmann, J. D. Kurfess, P. Blanco, D. Bhattacharya. 1997-07-21. Hard X-ray Emission from Cassiopeia A SNR. https://doi.org/10.1063/1.53930

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