Collimated synchrotron threads linking the radio lobes of ESO 137-006

Abstract

We present MeerKAT 1000 MHz and 1400 MHz observations of a bright radio galaxy in the southern hemisphere, ESO 137-006. The galaxy lies at the centre of the massive and merging Norma galaxy cluster. The MeerKAT continuum images (rms ∼0.02 mJy beam−1 at ∼10″ resolution) reveal new features that have never been seen in a radio galaxy before: collimated synchrotron threads of yet unknown origin, which link the extended and bent radio lobes of ESO 137-006. The most prominent of these threads stretches in projection for about 80 kpc and is about 1 kpc in width. The radio spectrum of the threads is steep, with a spectral index of up to α ≃ 2 between 1000 and 1400 MHz.