Astronomers have confirmed a powerful radio galaxy from nearly 12.5 billion years ago. The source, TXS 2354+015, was originally identified as a high-redshift candidate from its characteristic drop in optical light, and follow-up spectroscopy placed it at a redshift of 4.946. Their paper was posted to the arXiv preprint server on Sept. 23.

When material falls onto a galaxy’s central supermassive black hole, the resulting accretion activity can power an active galactic nucleus (AGN) and launch powerful relativistic jets of plasma, producing large amounts of radio waves. Such a galaxy is called a radio-loud active galactic nucleus (RLAGN). The energy that the jets carry can influence star formation in the galaxy and heat its surrounding gas.

This “AGN feedback” is incorporated in simulations to correctly predict the number of galaxies in the universe. Such powerful galaxies in the early universe—called high-z RLAGNs—tend to mark the locations of the most massive, earliest-forming galaxies and galaxy clusters.