Discovery of an unusual radio galaxy with a hybrid double-double and X-shaped morphology

摘要

We report the discovery of the first 'X'-shaped double-double radio galaxy (DDRG), MRC0929+164 (J0932+1611), from FIRST radio survey. The intersection angle of the lines of two pairs of radio lobes is around 20.6° for this object, much larger than other DDRGs. This unusual morphology may be a hint that the growth of its central super-massive black hole suffered a violent galaxy merger once.