Discovery of recombining plasma in the supernova remnant 3C 391

作者：Sat Tamotsu^*; Koyama Katsuji; Takahashi Tadayuki; Odaka Hirokazu; Nakashima Shinya

来源：Publications of the Astronomical Society of Japan, 2014, 66(6): 124.

DOI：10.1093/pasj/psu120

• ISM: individual objects (3C 391 G31.9+0.0)
• ISM: abundances
• ISM: supernova remnants
• X-rays: ISM

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 Ly alpha line at 2.006 keV, a S XVI Ly alpha 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-circle dot. 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 K alpha line at 6.4 keV (2.4 sigma detection) from the south-east region of the SNR.

• 出版日期2014-12