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We present the discovery of an active galactic nucleus (AGN) that is turningoff and then on again in the z=0.06 galaxy SDSS J1354+1327. This episodicnuclear activity is the result of discrete accretion events, which could havebeen triggered by a past interaction with the companion galaxy that iscurrently located 12.5 kpc away. We originally targeted SDSS J1354+1327 becauseits Sloan Digital Sky Survey spectrum has narrow AGN emission lines thatexhibit a velocity offset of 69 km s$^{-1}$ relative to systemic. To determinethe nature of the galaxy and its velocity-offset emission lines, we observedSDSS J1354+1327 with Chandra/ACIS, Hubble Space Telescope/Wide Field Camera 3,Apache Point Observatory optical longslit spectroscopy, and Keck/OSIRISintegral-field spectroscopy. We find a ~10 kpc cone of photoionized gas southof the galaxy center and a ~1 kpc semi-spherical front of shocked gas, which isresponsible for the velocity offset in the emission lines, north of the galaxycenter. We interpret these two outflows as the result of two separate AGNaccretion events; the first AGN outburst created the southern outflow, and then$<10^5$ yrs later the second AGN outburst launched the northern shock front.SDSS J1354+1327 is the galaxy with the strongest evidence for an AGN that hasturned off and then on again, and it fits into the broader context of AGNflickering that includes observations of AGN light echoes.

An Active Galactic Nucleus Caught in the Act of Turning Off and On