2019ApJ...870...62P

This paper reports a systematic search of X-ray cavities, density jumps, and shocks in the intergalactic environment of the galaxy group IC 1262 using Chandra, GMRT, and Very Large Array archival observations. The X-ray imaging analysis reveals a pair of X-ray cavities to the north and south of the X-ray peak, at projected distances of 6.48 kpc and 6.30 kpc respectively. Total mechanical power contained in both of these cavities is found to be ∼12.37 x 10⁴² erg s^–1, and compares well with the X-ray luminosity, within the cooling radius, measured to be ∼3.29 x 10⁴² erg s^–1, suggesting that the mechanical power injected by the central AGN efficiently balances the radiative loss. We detect a previously unknown X-ray cavity at the position of the southern radio lobe in the intra-group medium and find a loop of excess X-ray emission extending ∼100 kpc southwest from the central galaxy. The X-ray cavity at the position of the southern radio lobe probably represents a first generation X-ray cavity. Two surface brightness edges are evident to the west and northeast of the center of this group. The radio galaxy at the core of the IC 1262 group is a rare low-redshift ultra-steep radio galaxy, its spectral index being α ∼ -1.73 (including the central AGN) and α ∼ -2.08 (excluding the central AGN). We detect a radio phoenix embedded within the southern radio lobe, for the first time in a poor group, with a spectral index (α <= -1.92). The spectral index distribution across the phoenix steepens with increasing distance from its intensity peak.