IC 2497

{{Short description|Spiral galaxy in the constellation Leo Minor}}

{{Infobox galaxy

| name = IC 2497

| image = 250px

| caption = IC 2497 with Hanny's Voorwerp by HST
Credit: NASA, ESA, W. Keel (University of Alabama), and the Galaxy Zoo Team

| constellation name = Leo Minor {{cite web|work=Sky Factory|url=http://www.skyfactory.org/deepskycatalogue/IC2497.html|archive-url=https://web.archive.org/web/20080221154401/http://www.skyfactory.org/deepskycatalogue/IC2497.html|url-status=usurped|archive-date=February 21, 2008|title=IC 2497|author=Davide De Martin|date=2007|access-date=2010-11-11}}

| epoch = J2000.0

| ra = {{RA|09|41|04.076}}

| dist_ly = {{convert|650|Mly|Mpc|2|lk=on|abbr=on}}

| dec = {{DEC|+34|43|58.57}}

| size_v = 0.390' × 0.320'

| z = 0.051633

| names = {{odlist|IC=2497|LEDA=165538|PGC=165538|IRAS=09380+3457|2MASX=J09410407+3443585}}

}}

IC 2497 is a spiral galaxy{{cite web|work=BBC News|url=http://news.bbc.co.uk/2/hi/science/nature/7543776.stm|title=Teacher finds new cosmic object|author=Paul Rincon|date=5 August 2008|access-date=2010-11-11}} close to the intergalactic cloud Hanny's Voorwerp.{{cite simbad|title=IC 2497|accessdate=2010-11-11}} The galaxy is a former quasar, whose light lit up Hanny's Voorwerp, which is now a light echo of that extinct quasar.{{cite web|work=ScienceDaily|url=https://www.sciencedaily.com/releases/2010/11/101103171638.htm|title=Cosmic Curiosity Reveals Ghostly Glow of Dead Quasar|date=6 November 2010|access-date=2010-11-10}} It is about {{convert|45000|-|70000|ly|pc}} away from Hanny's Voorwerp.{{cite web|work=Softpedia|url=http://news.softpedia.com/news/Shut-Down-Quasar-Found-Close-By-164389.shtml|title=Shut Down Quasar Found Close By|author=Tudor Vieru|date=3 November 2010|access-date=2010-10-11}} The quasar shut down sometime in the last 70,000 years.{{cite web|work=Universe Today|url=http://www.universetoday.com/77280/what-hannys-voorwerp-reveals-about-quasar-deaths/|title=What Hanny's Voorwerp Reveals About Quasar Deaths|author=Jon Voisey|date=3 November 2010|access-date=2010-11-11}} This revises current theories of quasar operation, as the quasar is quiescent, shutting down much faster than was thought possible,{{cite web|work=ECN Magazine|url=http://www.ecnmag.com/News/2010/11/Cosmic-Curiosity-Reveals-Ghostly-Glow-of-Dead-Quasar/|title=Cosmic Curiosity Reveals Ghostly Glow of Dead Quasar|archive-url=https://web.archive.org/web/20110719115142/http://www.ecnmag.com/News/2010/11/Cosmic-Curiosity-Reveals-Ghostly-Glow-of-Dead-Quasar/|archive-date=2011-07-19|publisher=Yale University|date=3 November 2010|access-date=2010-11-11}} and is much cooler than predicted. The galaxy is currently 100 to 10,000 times dimmer than it was when its quasar burned into Hanny's Voorwerp.{{cite magazine|magazine=Wired|url=https://www.wired.com/wiredscience/2010/11/quasar-shutdown/|title=Rare Dead Quasar Found in Nearby Galaxy|author=Lisa Grossman|date=2 November 2010|access-date=2010-11-11}}

One supernova has been observed in IC 2497: SN 2020ilb (type Ia, mag. 19) was discovered on 29 April 2020.[https://www.wis-tns.org/object/SN 2020ilb Transient Name Server entry for SN SN 2020ilb.] Retrieved 26 March 2023.