Probing quasar shutdown timescales with Hanny's Voorwerp

D.A. Evans, K. Schawinski, S. Virani, C.M. Urry, W.C. Keel, P. Natarajan, C.J. Lintott, A. Manning, P. Coppi, S. Kaviraj, S.P. Bamford, G.I.G. Józsa, M. Garrett, H. Van Arkel, P. Gay, L. Fortson

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Galaxy formation is significantly modulated by energy output from supermassive black holes at the centers of galaxies which grow in highly efficient luminous quasar phases. The timescale on which black holes transition into and out of such phases is, however, unknown. We present the first measurement of the shutdown timescale for an individual quasar using Suzaku and XMM-Newton X-ray observations of the nearby galaxy IC 2497, which hosted a luminous quasar no more than ∼230,000 years ago that is still seen as a light echo in 'Hanny's Voorwerp', but whose presentday radiative output is lower by at least 2 and more likely by over 4 orders of magnitude. This extremely rapid shutdown provides new insights into the physics of accretion in supermassive black holes, and may signal a transition of the accretion disk to a radiatively inefficient state. These results were first presented by [1].
Original languageEnglish
Title of host publicationSUZAKU 2011: Exploring the X-ray Universe: Suzaku and Beyond
EditorsRob Petre, Kazuhisa Mitsuda, Lorella Angelini
PublisherAmerican Institute of Physics (AIP)
ISBN (Print)9780735410107, 0735410100
Publication statusPublished - 2012
EventSuzaku 2011: Exploring the X-Ray Universe: Suzaku and Beyond - SLAC National Accelerator Laboratory, Menlo Park, California, United States
Duration: 20 Jul 201122 Jul 2011

Publication series

NameAIP Conf Procs


ConferenceSuzaku 2011: Exploring the X-Ray Universe: Suzaku and Beyond
Country/TerritoryUnited States
CityMenlo Park, California


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