Studying the radiative recombination continua in the X-ray spectra of pure ejecta and of overionized plasmas
Abstract
Several Supernova Remnants (SNRs) show signatures of over ionization. A plasma is over ionized when its ionization state is higher than that expected from its electron temperature, namely when it is non-equilibrium of ionization and in recombining phase. The physical origin of over ionized plasma in SNRs is largely debated in the literature. The characteristic feature of a recombining plasma in the X-rays is the presence of prominent Radiative Recombination Continua (RRC), associated with electron recombining with ions. However, the intensity of the RRCs in the X-rays also increases with the plasma metallicity. We here present a thorough spectral study to investigate whether the bright RRC originating from a pure ejecta plasma in collisional ionization equilibrium can mimic that of an over ionized plasma in non-equilibrium of ionization. We performed series of spectral simulations in the X-rays, by exploring different values of temperature, emission measure, and chemical abundances. We also considered spectra emerging from a combination of interstellar medium and pure ejecta and compared them against actual observations of recombining SNRs. We present here some preliminary results and discuss in which conditions pure ejecta plasma in collisional ionization equilibrium might mimic features usually attributed to over ionized plasma in non-equilibrium of ionization.
- Publication:
-
Supernova Remnants: An Odyssey in Space after Stellar Death II
- Pub Date:
- June 2019
- Bibcode:
- 2019sros.confE.144G