Synoptic study of the SMC SNRs using XMM-Newton

¹ SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
² South African Astronomical Observatory, PO Box 9, Observatory 7935, Cape Town, South Africa

Corresponding author: K. J. van der Heyden, heyden@saao.ac.za

Received: 4 August 2003
Accepted: 11 March 2004

Abstract

We present a detailed X-ray spectral analysis of 13 supernova remnants (SNR) in the Small Magellanic Cloud (SMC). We apply both single-temperature non-equilibrium ionisation models and models based on the Sedov similarity solution, where applicable. We also present detailed X-ray images of individual SNRs, which reveal a range of different morphological features. Eight remnants, DEM S 32, IKT 2, HFPK 419, IKT 6, IKT 16, IKT 18 and IKT 23, are consistent with being in their Sedov evolutionary phase. IKT 6 and IKT 23 both have a clear shell like morphology with oxygen-rich X-ray emitting material in the centre. We draw attention to similarities between these two remnants and the well studied, oxygen-rich remnant IKT 22 (SNR 0102-72.3) and propose that they are more evolved versions of IKT 22. IKT 5, DEM S 128 and IKT 25 are evolved remnants which are in, or in the process of entering, the radiative cooling stage. The X-ray emission from these three remnants is possibly from the ejecta remains of type Ia SNe. Our modeling allows us to derive estimates for physical parameters, such as densities, ages, masses and initial explosion energies. Our results indicate that the average SMC hydrogen density is a factor of lower as compared to the Large Magellanic Cloud. This has obvious implications for the evolution and luminosities of the SMC SNRs. We also estimate the average SMC gas phase abundances for the elements O, Ne, Mg, Si and Fe.