IC 2497 explained

IC 2497
Constellation Name:	Leo Minor ^[1]
Epoch:	J2000.0
Dist Ly:	650Mly
Size V:	0.390' × 0.320'
Z:	0.051633

IC 2497 is a spiral galaxy^[2] close to the intergalactic cloud Hanny's Voorwerp.^[3] The galaxy 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 45000ly70000ly 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]

One supernova has been observed in IC 2497: SN 2020ilb (type Ia, mag. 19) was discovered on 29 April 2020.^[9]

Further reading

• Schawinski . K. . etal . 2010 . The Sudden Death of the Nearest Quasar . . 724 . 1 . L30–L33 . 1011.0427 . 2010ApJ...724L..30S . free . 10.1088/2041-8205/724/1/L30 . free.
• Rampadarath . H. . etal . 2010 . Hanny's Voorwerp . . 517 . L8 . 1006.4096 . 2010A&A...517L...8R . free . 10.1051/0004-6361/201014782 . free.
• Józsa . G. I. G. . etal . 2009 . Revealing Hanny's Voorwerp: Radio observations of IC 2497 . . 500 . 2 . L33–L36 . 0905.1851 . 2009A&A...500L..33J . free . 10.1051/0004-6361/200912402 . free.

Notes and References

1. Web site: Sky Factory. IC 2497. Davide De Martin. 2007. 2010-11-11.
2. Web site: BBC News. Teacher finds new cosmic object. Paul Rincon. 5 August 2008. 2010-11-11.
3. IC 2497. 2010-11-11.
4. Web site: ScienceDaily. Cosmic Curiosity Reveals Ghostly Glow of Dead Quasar. 6 November 2010. 2010-11-10.
5. Web site: Softpedia. Shut Down Quasar Found Close By. Tudor Vieru. 3 November 2010. 2010-10-11.
6. Web site: Universe Today. What Hanny's Voorwerp Reveals About Quasar Deaths. Jon Voisey. 3 November 2010. 2010-11-11.
7. Web site: ECN Magazine. Cosmic Curiosity Reveals Ghostly Glow of Dead Quasar. https://web.archive.org/web/20110719115142/http://www.ecnmag.com/News/2010/11/Cosmic-Curiosity-Reveals-Ghostly-Glow-of-Dead-Quasar/. 2011-07-19. Yale University. 3 November 2010. 2010-11-11.
8. Wired. Rare Dead Quasar Found in Nearby Galaxy. Lisa Grossman. 2 November 2010. 2010-11-11.
9. https://www.wis-tns.org/object/SN 2020ilb Transient Name Server entry for SN SN 2020ilb.