A Compact Group of Galaxies at z = 2.48 hosting an AGN-Driven Outflow
  We present observations of a remarkable compact group of galaxies at $z =
2.48$. Four galaxies, all within 40 kpc of each other, surround a powerful high
redshift radio source. This group comprises two compact red passive galaxies
and a pair of merging galaxies. One of the red galaxies, with an apparent
stellar mass of $3.6\times10^{11} M_{\odot}$ and an effective radius of 470 pc,
is one of the most extreme examples of a massive quiescent compact galaxy found
so far. One of the pair of merging galaxies hosts the AGN producing the large
powerful radio structure. The merger is massive and enriched, consistent with
the mass-metallicity relation expected at this redshift. Close to the merging
nuclei, the emission lines exhibit broad and asymmetric profiles that suggest
outflows powered either by a very young expanding radio jet or by AGN
radiation. At $\gtrsim 50$ kpc from the system, we found a fainter
extended-emission region that may be a part of a radio jet-driven outflow.
