A GMRT study of Seyfert galaxies NGC 4235 and NGC 4594: evidence of episodic activity?

Low-frequency observations at 325 and 610 MHz have been carried out for two ‘radio-loud’ Seyfert galaxies, NGC 4235 and NGC 4594 (Sombrero galaxy), using the Giant Meterwave Radio Telescope (GMRT). The 610 MHz total intensity and 325–610 MHz spectral index images of NGC 4235 tentatively suggest the presence of a ‘relic’ radio lobe, most likely from a previous episode of active galactic nucleus (AG...