![]() MRC 0116 + 111 is a nearby (z = 0.132) poor galaxy group, which was previously known for exhibiting a bright diffuse radio emission with no central point-like source, presumably related to a past activity of the active galactic nucleus (AGN) in its central cD galaxy. Although, interestingly, the radio source was reported with a surprisingly high luminosity (L 621 MHz ∼ 1.21 × 10 25 W Hz −1 and L 1.4 GHz ∼ 4.57 × 10 24 W Hz −1 ) and with a mini-halo-like morphology (without emission from the central SMBH), no X-ray observation of MRC 0116 has been reported so far in the literature. 2009) suggests instead a rather poor galaxy group. 2004), the limited number of galaxies seen in the optical band (Bagchi et al. Although, based on optical observations, the source had also been firmly classified as a galaxy cluster (Lopes et al. 2009, where the authors find the dominant galaxy to be at z = 0.1316). 2002), then discussed in detail with more recent GMRT and optical observations (Bagchi et al. 1981) -had been reported a first time using the Giant Metrewave Radio Telescope (GMRT) and the Very Large Array (VLA) data (Gopal-Krishna et al. Initially discovered by the Ooty Lunar Occultation Survey at 327 MHz (Joshi & Singal 1980), this radio source -also member of the Molonglo Reference Catalogue (Large et al. Therefore, this source presents an excellent opportunity to understand the energetics and the dynamical evolution of radio jet inflated plasma bubbles in the hot cluster atmosphere. We estimate that the radio jets which inflated these two bubbles might have also fed enough energy into the intracluster medium to create an enormous system of cavities and shock fronts, and to drive a massive outflow from the AGN, which could counter-balance and even quench a cooling flow. The other bubble, closer to the cluster centre, shows signs of ongoing particle re-acceleration. ![]() The extremely steep high-frequency radio spectrum of the north-western bubble, located ~100kpc from cluster centre, indicates radiation losses, possibly because having detached, it is rising buoyantly and moving away into the putative hot intracluster medium. ![]() The radio emitting relativistic particles and magnetic fields were probably seeded in the past by a pair of radio jets originating in the AGN of the central cD galaxy. However, in MRC0116+111 we do not detect any ongoing active galactic nucleus (AGN) activity, such as a compact core or active radio jets feeding the plasma bubbles. Our optical and multiwavelength Giant Metrewave Radio Telescope and Very Large Array radio observations reveal a highly unusual radio source: showing a pair of giant (~100-kpc diameter) bubble-like diffuse structures, that are about three times larger than the analogous extended radio emission observed in M87 - the dominant central radio galaxy in the Virgo cluster. We present detailed observations of MRC0116+111, revealing a luminous, miniradio halo of ~240-kpc diameter located at the centre of a cluster of galaxies at redshift z = 0.131.
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