We present the first results of a deep Chandra observation of the galaxy cluster RBS 797 whose previous X-ray studies revealed two pronounced X-ray cavities in the east–west (E–W) direction. Follow-up VLA radio observations of the central active galactic nucleus (AGN) uncovered different jet and lobe orientations, with radio lobes filling the E–W cavities and perpendicular jets showing emission in the north–south (N–S) direction over the same scale (≈30 kpc). With the new ∼427 ks total exposure, we report the detection of two additional, symmetric X-ray cavities in the N–S direction at nearly the same radial distance as the E–W ones. The newly discovered N–S cavities are associated with the radio emission detected at 1.4 and 4.8 GHz in archival VLA data, making RBS 797 the first galaxy cluster found to have four equidistant, centrally symmetric, radio-filled cavities. We derive the dynamical and radiative ages of the four cavities from X-ray and radio data, respectively, finding that the two outbursts are approximately coeval, with an age difference of ⪅10 Myr between the E–W and N–S cavities. We discuss two scenarios for the origin of the two perpendicular, equidistant cavity systems: either the presence of a binary AGN that is excavating coeval pairs of cavities in perpendicular directions or a fast (<10 Myr) jet reorientation event that produced subsequent, misaligned outbursts.

We present the first X-ray dedicated study of the galaxy cluster A795 and of the Fanaroff-Riley Type 0 hosted in its brightest cluster galaxy. Using an archival 30 ks Chandra observation we study the dynamical state and cooling properties of the intracluster medium, and we investigate whether the growth of the radio galaxy is prevented by the surrounding environment. We discover that A795 is a weakly cool core cluster, with an observed mass deposition rate ⪅14  M⊙yr−1 in the cooling region (central ∼66 kpc). In the inner ∼ 30 kpc we identify two putative X-ray cavities, and we unveil the presence of two prominent cold fronts at ∼60 kpc and ∼178 kpc from the center, located along a cold ICM spiral feature. The central galaxy, which is offset by 17.7 kpc from the X-ray peak, is surrounded by a multi-temperature gas with an average density of ne = 2.14 × 10−2 cm−3. We find extended radio emission at 74-227 MHz centered on the cluster, exceeding the expected flux from the radio galaxy extrapolated at low frequency. We propose that sloshing is responsible for the spiral morphology of the gas and the formation of the cold fronts, and that the environment alone cannot explain the compactness of the radio galaxy. We argue that the power of the two cavities and the sloshing kinetic energy can reduce and offset cooling. Considering the spectral and morphological properties of the extended radio emission, we classify it as a candidate radio mini-halo.