Multi-frequency study of the newly confirmed supernova remnant MCSNR J0512-6707 in the Large Magellanic Cloud
Abstract
Aims: We present a multi-frequency study of the supernova remnant MCSNR J0512-6707 in the Large Magellanic Cloud.
Methods: We used new data from XMM-Newton to characterise the X-ray emission and data from the Australian Telescope Compact Array, the Magellanic Cloud Emission Line Survey, and Spitzer to gain a picture of the environment into which the remnant is expanding. We performed a morphological study, determined radio polarisation and magnetic field orientation, and performed an X-ray spectral analysis.
Results: We estimated the remnant's size to be 24.9 ( ± 1.5) × 21.9 ( ± 1.5) pc, with the major axis rotated ~29° east of north. Radio polarisation images at 3 cm and 6 cm indicate a higher degree of polarisation in the northwest and southeast tangentially oriented to the SNR shock front, indicative of an SNR compressing the magnetic field threading the interstellar medium. The X-ray spectrum is unusual as it requires a soft (~0.2 keV) collisional ionisation equilibrium thermal plasma of interstellar medium abundance, in addition to a harder component. Using our fit results and the Sedov dynamical model, we showed that the thermal emission is not consistent with a Sedov remnant. We suggested that the thermal X-rays can be explained by MCSNR J0512-6707 having initially evolved into a wind-blown cavity and is now interacting with the surrounding dense shell. The origin of the hard component remains unclear. We could not determine the supernova type from the X-ray spectrum. Indirect evidence for the type is found in the study of the local stellar population and star formation history in the literature, which suggests a core-collapse origin.
Conclusions: MCSNR J0512-6707 likely resulted from the core-collapse of high mass progenitor which carved a low density cavity into its surrounding medium, with the soft X-rays resulting from the impact of the blast wave with the surrounding shell. The unusual hard X-ray component requires deeper and higher spatial resolution radio and X-ray observations to confirm its origin.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- November 2015
- DOI:
- 10.1051/0004-6361/201526987
- arXiv:
- arXiv:1509.06475
- Bibcode:
- 2015A&A...583A.121K
- Keywords:
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- ISM: supernova remnants;
- Magellanic Clouds;
- X-rays: ISM;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 11 pages, 7 figures, accepted for publication in Astronomy and Astrophysics. arXiv admin note: text overlap with arXiv:1505.06458