Kazuhiro Nakazawa

Non-thermal components in the intra-cluster medium (ICM), such as turbulence, magnetic field, and cosmic rays, imprint the past and current energetic activities of jets from active galactic nuclei (AGN) of member galaxies as well as disturbance caused by galaxy cluster mergers. Meter- and centimeter-radio observations of synchrotron radiation allow us to diagnose the nonthermal component. Here we report on our discovery of an unidentified diffuse radio source, named the Flying Fox, near the center of the Abell 1060 field. The Flying Fox has an elongated ring-like structure and a central bar shape, but there is no obvious host galaxy. The average spectral index of the Flying Fox is −1.4, which is steeper than that for radio sources seen at meter wavelengths. We discussed the possibilities of radio lobes, phoenixes, radio halos and relics, and an odd radio circle. In conclusion, the Flying Fox is not clearly explained by known radio sources.