Active galactic nuclei

Hotspot ages rising with distance point to four jet outbursts from one black hole

Astronomers led by IISER Pune's Pavan Vijay Khadekar report four pairs of radio hotspots, aged 4.5 to 20.5 million years, around one elliptical galaxy. Their preprint makes the case for the first known quadruple-double radio galaxy, a dated record of one black hole's restarts that wider surveys would need to turn into a rate.