Discovery of recombining plasma in the supernova remnant 3C 391
Abstract
Recent X-ray study of middle-aged supernova remnants (SNRs) reveals strong radiative recombination continua (RRCs) associated with overionized plasmas, which origin still remains uncertain. We report a discovery of an RRC in the middle-aged SNR 3C 391. If the X-ray spectrum is fitted with a two-temperature plasma model in collisional ionization equilibrium (CIE), residuals of a Si XIV Lyα line at 2.006 keV, a S XVI Lyα line at 2.623 keV and the edge of a RRC of Si XIII at 2.666 keV are found. In fact, the X-ray spectrum is well described by the composite model consisting of the CIE plasma and a recombining plasma (RP). The abundance pattern suggests that the RP is due to ejecta from core-collapse supernova of the progenitor mass of about 15 M⊙. There is no significant difference of the recombining parameters between the south-east region and the north-west region surrounded by dense molecular clouds. We also find a hint of a Fe I Kα line at 6.4 keV (2.4 σ detection) from the south-east region of the SNR.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- December 2014
- DOI:
- 10.1093/pasj/psu120
- arXiv:
- arXiv:1409.6861
- Bibcode:
- 2014PASJ...66..124S
- Keywords:
-
- ISM: individual objects (3C 391;
- G31.9+0.0);
- ISM: abundances;
- ISM: supernova remnants;
- X-rays: ISM;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 15 pages, 8 figures, accepted for publication in PASJ