Suzaku X-ray observations of a young supernova remnant, Cassiopeia A, were carried out. K-shell transition lines from highly ionized ions of various elements were detected, including Chromium (Cr-Ka at 5.61 keV). The X-ray continuum spectra were modeled in the 3.4 - 40keV band, summed over the entire remnant, and were fitted with a simplest combination of the thermal bremsstrahlung and the non-thermal cut-off power-law models. The spectral fits with this assumption indicate that the continuum emission is likely to be dominated by non-thermal emission with a cut-off energy at > 1 keV The thermal-to-nonthermal fraction of the continuum flux in the 4-10keV band is best estimated as ∼ 0.1. Non-thermal-dominated continuum images in the 4-14 keV band were made. The peak of the non-thermal X-rays appears at the western part. The peak position of the TeV γ-rays measured with HEGRA and MAGIC is also shifted at the western part with the 1-sigma confidence. Since the location of the X-ray continuum emission was known to be presumably identified with the reverse shock region, the possible keV-TeV correlations give a hint that the accelerated multi-TeV hadrons in Cassiopeia A are dominated by heavy elements in the reverse shock region.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
- Cosmic rays - Ism
- Individual (cassiopeia a) - Ism
- Supernova remnants