Abstract
Here we present a radio continuum study based on new and archival data from the Australia Telescope Compact Array towards N 103B, a young (<=1000 yrs) spectroscopically confirmed type Ia SNR in the Large Magellanic Cloud (LMC) and proposed to have originated from a single degenerate progenitor. The radio morphology of this SNR is asymmetrical with two bright regions towards the north-west and south-west of the central location as defined by radio emission. N 103B identified features include: a radio spectral index of -0.75+-0.01 (consistent with other young type Ia SNRs in the Galaxy); a bulk SNR expansion rate as in X-rays; morphology and polarised electrical field vector measurements where we note radial polarisation peak towards the north-west of the remnant at both 5500 and 9000 MHz. The spectrum is concave-up and the most likely reason is the non-linear diffusive shock acceleration effects or presence of two different populations of ultra-relativistic electrons. We also note unpolarized clumps near the south-west region which is in agreement with this above scenario. We derive a typical magnetic field strength for N 103B, of 16.4 microG for an average rotation measurement of 200 rad m^-2. However, we estimate the equipartition field to be of the order of ~235 microG with an estimated minimum energy of Emin=6.3*10^48 erg. The close (~0.5 degree) proximity of N 103B to the LMC mid-plane indicates that an early encounter with dense interstellar medium may have set an important constrain on SNR evolution. Finally, we compare features of N 103B, to six other young type Ia SNRs in the LMC and Galaxy, with a range of proposed degeneracy scenarios to highlight potential differences due to a different models. We suggest that the single degenerate scenario might point to morphologically asymmetric type Ia supernova explosions.
Highlights
Supernovae (SNe) play important roles in cosmology
The surface brightness to diameter diagram The position of Large Magellanic Cloud (LMC) supernova remnants (SNRs) N 103B in the surface brightness to diameter ( –D) diagram ( = 6 × 10−19 W m−2 Hz−1 sr−1, D = 6.8 pc) by Pavlovicet al. (2018), suggests that this remnant is in the early Sedov phase, with an explosion energy of 1–1.5 × 1051 erg, which evolves in an environment with a density of 0.02–0.2 cm−3
We suggest that the most likely reason is the non-linear diffusive shock acceleration (NLDSA) effects or presence of two different population of ultra-relativistic electrons
Summary
Supernovae (SNe) play important roles in cosmology. Type Ia SNe have been used as standard candles to constrain cosmological parameters, providing the first and best evidence of cosmic acceleration and dark energy (Riess et al 1998; Perlmutter et al 1999). Type Ia SNe (a.k.a. thermonuclear (TN)) are believed to occur when a white dwarf (WD) close to the Chandrasekhar mass, reigniting explosive nuclear reactions This is most likely to occur in a binary system, either by the accretion from a non-degenerate companion star (the socalled single degenerate scenario, SD) or via a merger with another WD (double degenerate scenario, DD). The ratio of SN Ia to CC explosions is lower in large disk galaxies (like the Milky Way) than in dwarf irregular galaxies, implying that Galactic environment and different star formation rate (SFR) cannot be ignored (Tsujimoto et al 1995) This effect is been shown by the recent observational evidence from nearby dwarfs– Magellanic Clouds (see Maggi et al 2016).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
