MeerKAT reveals a ghostly thermal radio ring towards the Galactic Centre

Abstract

We present the serendipitous discovery of a new radio-continuum ring-like object nicknamed Kyklos (J1802-3353), with MeerKAT UHF and L-band observations. The radio ring, which resembles the recently discovered odd radio circles (ORCs), has a diameter of 80 arcsec and is located just 6 deg from the Galactic plane. However, Kyklos exhibits an atypical thermal radio-continuum spectrum (α = -0.1 +/- 0.3), which led us to explore different possible formation scenarios. We concluded that a circumstellar shell around an evolved massive star, possibly a Wolf-Rayet, is the most convincing explanation with the present data.

7 pages, 5 figures, accepted in A&A

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• The SARAO MeerKAT Galactic Plane Survey extended source catalogue
• Evolutionary Map of the Universe: Detection and Analysis of the Shell Surrounding the Runaway Wolf-Rayet Star WR16
• MeerKAT discovery of 164 compact radio rings toward the Galactic Plane
• Deep polarimetry study reveals double ring ORC-like structures