The newly operational X-ray satellite Suzaku observed the southwestern quadrant of the supernova remnant (SNR) RCW 86 in February 2006 to study the nature of the 6.4 keV emission line. The new data localize it for the first time; most of the line emission is adjacent and interior to the forward shock and not at the locus of the continuum hard emission. We also report the first detection of a 7.1 keV line that we interpret as the Kβ emission from low-ionization iron. The Fe-K line features are consistent with a non-equilibrium plasma of Fe-rich ejecta with net > 109 cm-3 s and kTe ∼ 5 keV. This combination of low net and high kTe suggests collisionless electron heating in an SNR shock. The Fe Ka line shows evidence for intrinsic broadening, with a width of 47 (34-59) eV (99% error region). The difference of the spatial distributions of the hard continuum above 3 keV and the Fe-K line emission support a synchrotron origin for the hard continuum.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)