An M1 flare produced strong type III, II, and IV radio bursts, for a period of 3 hours.
Please see:
http://herrero.freei.me/events1008/
Hercules A
Radio-Optical View of the Galaxy Hercules A - Many thanks to: NASA, ESA, S. Baum and C. O'Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA)