Multi-frequency study of the newly confirmed supernova remnant MCSNR J0512−6707 in the Large Magellanic Cloud

P. J. Kavanagh (1) , M. Sasaki (1) , L. M. Bozzetto (2) , S. D. Points (3) , M. D. Filipović (2) , P. Maggi (4) , F. Haberl (5) , E. J. Crawford (2)

1 Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen
2 Western Sydney University
3 Cerro Tololo Inter-American Observatory
4 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
5 MPE - Max-Planck-Institut für Extraterrestrische Physik

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.

Mots clés: ISM: supernova remnants; Magellanic Clouds; X-rays: ISM

Domaines: Astrophysique [astro-ph]

P. J. Kavanagh, M. Sasaki, L. M. Bozzetto, S. D. Points, M. D. Filipović, et al.. Multi-frequency study of the newly confirmed supernova remnant MCSNR J0512−6707 in the Large Magellanic Cloud. Astronomy and Astrophysics - A&A, 2015, 583, pp.A121. ⟨10.1051/0004-6361/201526987⟩. ⟨cea-01383761⟩