| 4th of April 2018 |
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| The Puppis A supernova remnant |
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Reynoso et al. present a polarization study towards the relatively
young supernova remnant Puppis A, based on observations performed with
the Australia Telescope Compact Array. Based on the analysis of a
feature detected outside the SNR shell, they were able to disentangle
the emission originating in Puppis A itself from that coming from the
foreground Vela SNR. They found a very low polarization fraction, of
about 3 percent on average, and placed an upper limit on the magnetic
field component parallel to the line of sight of about 20
microgauss. There is evidence that the magnetic vectors along the
shell are aligned with the shock front direction. The low polarization
fraction and the statistical behavior of the magnetic vectors are
compatible with a scenario where the supernova remnant evolves inside
a stellar wind bubble launched by the supernova progenitor star. This
scenario can furthermore explain the morphology of Puppis A, rendering
little support to the previously accepted picture which involved
strong density gradients to explain the flat, eastern edge of the
shell.
The image above shows the polarized intensity of Puppis A at 2.24 GHz. The color scale, in mJy per beam, is shown in the bar at the right. Total intensity contours at 50, 100, 250, 600, and 1000 mJy per beam are overlaid in white. The yellow circle at the top right corner represents the 2 arcminute beam. Results are presented in the preprint of the paper. |