Volume 586, February 2016
|Number of page(s)||16|
|Section||Interstellar and circumstellar matter|
|Published online||19 January 2016|
Two evolved supernova remnants with newly identified Fe-rich cores in the Large Magellanic Cloud⋆
1 Institut für Astronomie und Astrophysik, Kepler Center for Astro and Particle Physics, Eberhard Karls Universität Tübingen, Sand 1, 72076 Tübingen, Germany
2 Western Sydney University, Locked Bag 1797, Penrith South DC, NSW 1797, Australia
3 Cerro Tololo Inter-American Observatory, Casilla 603, La Serena, Chile
4 Physics and Astronomy Department, University of New Mexico, MSC 07-4220, Albuquerque, NM 87131, USA
5 Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany
6 Laboratoire AIM, CEA-IRFU/CNRS/Université Paris Diderot, Service d’Astrophysique, CEA Saclay, 91191 Gif sur Yvette Cedex, France
Received: 21 September 2015
Accepted: 29 October 2015
Methods. We used observational data from XMM-Newton, the Australian Telescope Compact Array, and the Magellanic Cloud Emission Line Survey to study their broad-band emission and used Spitzer and H i data to gain a picture of the environment into which the remnants are expanding. We performed a multi-wavelength morphological study and detailed radio and X-ray spectral analyses to determine their physical characteristics.
Results. Both remnants were found to have bright X-ray cores, dominated by Fe L-shell emission, which is consistent with reverse shock-heated ejecta with determined Fe masses in agreement with Type Ia explosion yields. A soft X-ray shell, which is consistent with swept-up interstellar medium, was observed in MCSNR J0506−7025, suggestive of a remnant in the Sedov phase. Using the spectral fit results and the Sedov self-similar solution, we estimated the age of MCSNR J0506−7025 to be ~16−28 kyr, with an initial explosion energy of (0.07−0.84) × 1051 erg. A soft shell was absent in MCSNR J0527−7104, with only ejecta emission visible in an extremely elongated morphology that extends beyond the optical shell. We suggest that the blast wave has broken out into a low density cavity, allowing the shock heated ejecta to escape. We find that the radio spectral index of MCSNR J0506−7025 is consistent with the standard −0.5 for supernova remnants. Radio polarisation at 6 cm indicates a higher degree of polarisation along the western front and at the eastern knot with a mean fractional polarisation across the remnant of P ≅ (20 ± 6)%.
Conclusions. The detection of Fe-rich ejecta in the remnants suggests that both resulted from Type Ia explosions. The newly identified Fe-rich cores in MCSNR J0506−7025 and MCSNR J0527−7104 make them members of the expanding class of evolved Fe-rich remnants in the Magellanic Clouds.
Key words: ISM: supernova remnants / Magellanic Clouds / X-rays: ISM
© ESO, 2016
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.