2017/11/29 by R. Kothes, X. Sun, B. Gaensler +1 · 3 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Gamma-ray bursts and supernovae #Linear polarization #Magnetar #Magnetic field #Milky Way #Polarization (electrochemistry) #Pulsar #Pulsar wind nebula #Pulsars and Gravitational Waves Research #Spectral index #Supernova remnant #astro-ph.HE
paper · pdf · doi:10.3847/1538-4357/aa9e89
accepted by The Astrophysical Journal, 16 pages, 10 figures
arxiv created 2017/11/29 · openalex created_date 2017/12/22 · openalex publication_date 2018/01/01 · arxiv updated 2018/01/10 · openalex updated_date 2026/08/05
Abstract We present a radio continuum and linear polarization study of the Galactic supernova remnant (SNR) G57.2+0.8, which may host the recently discovered magnetar SGR 1935+2154. The radio SNR shows the typical radio continuum spectrum of a mature supernova remnant with a spectral index of 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, which 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 yr. The SNR has already entered the radiative or pressure-driven snowplow phase of its evolution. We compare independently determined characteristics like age and distance for both the SNR and the soft gamma repeater SGR 1935+2154, and conclude that they are physically related.