5.9-keV Mn K-shell X-ray luminosity from the decay of 55Fe in Type Ia supernova models

I. R. Seitenzahl, A. Summa, F. Krauß, S. A. Sim, R. Diehl, D. Elsässer, M. Fink, W. Hillebrandt, M. Kromer, K. Maeda, K. Mannheim, R. Pakmor, F. K. Röpke, A. J. Ruiter, J. Wilms

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16 Citations (Scopus)


We show that the X-ray line flux of the Mn Kα line at 5.9 keV from the decay of 55Fe is a promising diagnostic to distinguish between Type Ia supernova (SN Ia) explosion models. Using radiation transport calculations, we compute the line flux for two three-dimensional explosion models: a near-Chandrasekhar mass delayed detonation and a violent merger of two (1.1 and 0.9 M⊙) white dwarfs. Both models are based on solar metallicity zero-age main-sequence progenitors. Due to explosive nuclear burning at higher density, the delayed-detonation model synthesizes ˜3.5 times more radioactive 55Fe than the merger model. As a result, we find that the peak Mn Kα line flux of the delayed-detonation model exceeds that of the merger model by a factor of ˜4.5. Since in both models the 5.9-keV X-ray flux peaks five to six years after the explosion, a single measurement of the X-ray line emission at this time can place a constraint on the explosion physics that is complementary to those derived from earlier phase optical spectra or light curves. We perform detector simulations of current and future X-ray telescopes to investigate the possibilities of detecting the X-ray line at 5.9 keV. Of the currently existing telescopes, XMM-Newton/pn is the best instrument for close (≲1-2 Mpc), non-background limited SNe Ia because of its large effective area. Due to its low instrumental background, Chandra/ACIS is currently the best choice for SNe Ia at distances above ˜2 Mpc. For the delayed-detonation scenario, a line detection is feasible with Chandra up to ˜3 Mpc for an exposure time of 106 s. We find that it should be possible with currently existing X-ray instruments (with exposure times ≲5 × 105 s) to detect both of our models at sufficiently high S/N to distinguish between them for hypothetical events within the Local Group. The prospects for detection will be better with future missions. For example, the proposed Athena/X-IFU instrument could detect our delayed-detonation model out to a distance of ˜5 Mpc. This would make it possible to study future events occurring during its operational life at distances comparable to those of the recent supernovae SN 2011fe (˜6.4 Mpc) and SN 2014J (˜3.5 Mpc).
Original languageEnglish
Pages (from-to)1484-1490
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Early online date02 Jan 2015
Publication statusPublished - 01 Feb 2015


  • line: formation
  • nuclear reactions
  • nucleosynthesis
  • abundances
  • radiative transfer
  • supernovae: general
  • white dwarfs
  • X-rays: general


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