Progenitors and explosion properties of supernova remnants hosting central compact objects: I. RCW 103 associated with the peculiar source 1E 161348-5055

Abstract

We present a Chandra and XMM-Newton imaging and spectroscopic study of the supernova remnant (SNR) RCW 103 (G332.4-00.4) containing the central compact object 1E 161348-5055. The high-resolution Chandra X-ray images reveal enhanced emission in the south-eastern and north-western regions. Equivalent width line images of Fe L, Mg, Si, and S using XMM-Newton data were used to map the distribution of ejecta. The SNR was sectioned into 56 regions best characterized by two-component thermal models. The harder component (kT ∼ 0.6 keV) is adequately fitted by the VPSHOCK non-equilibrium ionization model with an ionization time-scale n_et ∼ 10¹¹-10¹² cm^-3 s, and slightly enhanced abundances over solar values. The soft component (kT ∼ 0.2 keV), fitted by the APEC model, is well described by plasma in collisional ionization equilibrium with abundances consistent with solar values. Assuming a distance of 3.1 kpc and a Sedov phase of expansion into a uniform medium, we estimate an SNR age of 4.4 kyr, a swept-up mass M_sw = 16f_ s^{-1/2} D_{3.1}^{5/2} M_⊙, and a low explosion energy E_* = 3.7 × 10⁴⁹ f_ s^{-1/2} D_{3.1}^{5/2} erg. This energy could be an order of magnitude higher if we relax the Sedov assumption, the plasma has a low filling factor, the plasma temperature is underestimated, or if the SNR is expanding into the progenitor's wind-blown bubble. Standard explosion models did not match the ejecta yields. By comparing the fitted abundances to the most recent core-collapse nucleosynthesis models, our best estimate yields a low-mass progenitor of around 12-13 M_⊙, lower than previously reported. We discuss degeneracies in the model fitting, particularly the effect of altering the explosion energy on the progenitor mass estimate.