The Cluster-central Compact Steep-spectrum Radio Galaxy 1321+045

The radio galaxy 1321+045 is a rare example of a young, compact steep-spectrum source located in the center of a z = 0.263 galaxy cluster. Using a combination of Chandra, VLBA, VLA, MERLIN, and IRAM 30 m observations, we investigate the conditions that have triggered this outburst. We find that the previously identified 5 kpc scale radio lobes are probably no longer powered by the active galactic nucleus, which seems to have launched a new similar to 20 pc jet on a different axis, likely within the last few hundred years. We estimate the enthalpy of the lobes to be 8.48(-3.56)(+6.04) x 10(57)erg, only sufficient to balance cooling in the surrounding 16 kpc for similar to 9 Myr. The properties of the cluster's intracluster medium (ICM) are similar to those of rapidly cooling nearby clusters, with a low central entropy (8.6(-1.4)(+2.2) keV cm(2) within 8 kpc), short central cooling time (390(-150)(+170) Myr), and t(cool)/t(ff) and t(cool)/t(eddy) ratios indicative of thermal instability out to similar to 45 kpc. Despite previous detection of H alpha emission from the brightest cluster galaxy, our IRAM 30 m observations do not detect CO emission in either the (1-0) or (3-2) transitions. We place 3 sigma limits on the molecular gas mass of M-mol <= 7.7 x 10(9) M-circle dot and <= 5.6 x 10(9) M-circle dot from the two lines respectively. We find indications of a recent minor cluster merger that has left a similar to 200 kpc tail of stripped gas in the ICM, and probably induced sloshing motions.