IC 2497

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IC 2497
Hannys voorwerp.jpg
IC 2497 with Hanny's Voorwerp by HST
Credit: NASA, ESA, W. Keel (University of Alabama), and the Galaxy Zoo Team
Observation data
Epoch J2000.0 [1]
Constellation Leo Minor [2]
Right ascension  09h 41m 04.076s [1]
Declination +34° 43′ 58.57″ [1]
Apparent dimension (V) 0.390' × 0.320' [1]
Redshift 0.051633 [1]
Other designations
IC 2497, LEDA 165538, IRAS 09380+3457, 2MASX J09410407+3443585

IC 2497 is a spiral galaxy[3] close to the intergalactic cloud Hanny's Voorwerp.[1]

IC 2497 is a former quasar, whose light lit up Hanny's Voorwerp, which is now a light echo of that extinct quasar.[4] It is about 45,000–70,000 light-years (14,000–21,000 pc) away from Hanny's Voorwerp.[5] The quasar shut down sometime in the last 70,000 years.[6] This revises current theories of quasar operation, as the quasar is quiescent, shutting down much faster than was thought possible,[7] and is much cooler than predicted.[5] The galaxy is currently 100 to 10,000 times dimmer than it was when its quasar burned into Hanny's Voorwerp.[8] It is currently the nearest known quasar, being 730 million light years away, and the one with the best view of its host galaxy.[8] The nearest active quasar is 3C 273, 1.7 billion light years further away.[9]


  1. ^ a b c d e f "IC 2497". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-11-11.
  2. ^ Sky Factory, "IC 2497", Davide De Martin, 2007 (accessed 2010-11-11)
  3. ^ BBC News, "Teacher finds new cosmic object", Paul Rincon, 5 August 2008 (accessed 2010-11-11)
  4. ^ ScienceDaily, "Cosmic Curiosity Reveals Ghostly Glow of Dead Quasar", 6 November 2010 (accessed 2010-11-10)
  5. ^ a b Softpedia, "Shut Down Quasar Found Close By", Tudor Vieru, 3 November 2010 (accessed 2010-10-11)
  6. ^ Universe Today, "What Hanny’s Voorwerp Reveals About Quasar Deaths", Jon Voisey, 3 November 2010 (accessed 2010-11-11)
  7. ^ ECN Magazine, "Cosmic Curiosity Reveals Ghostly Glow of Dead Quasar", Yale University, 3 November 2010 (accessed 2010-11-11)
  8. ^ a b Wired, "Rare Dead Quasar Found in Nearby Galaxy", Lisa Grossman, 2 November 2010 (accessed 2010-11-11)
  9. ^ PhysOrg, "'Cosmic ghost' discovered by volunteer astronomer", Yale University, 5 August 2008 (accessed 2010-10-11)

Further reading[edit]