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arXiv · 1711.11146

Radio continuum and polarization study of SNR G57.2+0.8 associated with magnetar SGR1935+2154

R. Kothes·X. Sun·B. Gaensler·W. Reich
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Abstract

We present a radio continuum and linear polarization study of the Galactic supernova remnant G57.2+0.8, which may host the recently discovered magnetar SGR1935+2154. The radio SNR shows the typical radio continuum spectrum of a mature supernova remnant with a spectral index of $α= -0.55 \pm 0.02$ and moderate polarized intensity. Magnetic field vectors indicate a tangential magnetic field, expected for an evolved SNR, in one part of the SNR and a radial magnetic field in the other. The latter can be explained by an overlapping arc-like feature, perhaps a pulsar wind nebula, emanating from the magnetar. The presence of a pulsar wind nebula is supported by the low average braking index of 1.2, we extrapolated for the magnetar, and the detection of diffuse X-ray emission around it. We found a distance of 12.5 kpc for the SNR, which identifies G57.2+0.8 as a resident of the Outer spiral arm of the Milky Way. The SNR has a radius of about 20 pc and could be as old as 41,000 years. The SNR has already entered the radiative or pressure-driven snowplow phase of its evolution. We compared independently determined characteristics like age and distance for both, the SNR and SGR1935+2154, and conclude that they are physically related.

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R. Kothes, X. Sun, B. Gaensler, W. Reich. 2017-11-29. Radio continuum and polarization study of SNR G57.2+0.8 associated with magnetar SGR1935+2154. https://doi.org/10.3847/1538-4357%2Faa9e89

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