A shock-induced pair of superbubbles in the high-redshift powerful radio galaxy MRC 0406-244

We present new optical spectroscopy of the high-redshift powerful radio gal axy MRC 0406-244 at redshift of 2.429. We find that the two extensions towa rd the northwest and southeast probed in the rest-frame ultraviolet image a re heated mainly by the nonthermal continuum of the active galactic nucleus . However, each extension shows a shell-like morphology, suggesting that th ey are a pair of superbubbles induced by the superwind activity rather than by the interaction between the radio jet and the ambient gas clouds. If th is is the case, the intense starburst responsible for the formation of supe rbubbles could occur similar to1 x 10(9) yr ago. On the other hand, the age of the radio jets may be on the order of similar to 10(6) yr, being much s horter than the starburst age. Therefore, the two events, i.e., the starbur st and the radio jet activities, are independent phenomena. However, their directions of the expanding motions could be governed by the rotational mot ion of the gaseous component in the host galaxy. This idea appears to expla in the alignment effect of MRC 0406-244.