Galaxy Zoo: 'Hanny's Voorwerp', a quasar light echo?

  title={Galaxy Zoo: 'Hanny's Voorwerp', a quasar light echo?},
  author={C. Lintott and K. Schawinski and W. Keel and H. V. Arkel and N. Bennert and E. Edmondson and Daniel I. Thomas and Daniel J. B. Smith and P. Herbert and M. Jarvis and S. Virani and D. Andreescu and S. Bamford and K. Land and P. Murray and R. Nichol and J. Raddick and A. Slosar and A. Szalay and J. vandenBerg},
  journal={Monthly Notices of the Royal Astronomical Society},
We report the discovery of an unusual object near the spiral galaxy IC 2497, discovered by visual inspection of the Sloan Digital Sky Survey (SDSS) as part of the Galaxy Zoo project. The object, known as Hanny’s Voorwerp, is bright in the SDSS g band due to unusually strong [O III]4959, 5007 emission lines. We present the results of the first targeted observations of the object in the optical, ultraviolet and X-ray, which show that the object contains highly ionized gas. Although the line… Expand
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