Editing Phoenix (constellation) (section)

===Deep-sky objects===
The constellation does not lie on the [[galactic plane]] of the Milky Way, and there are no prominent star clusters.<ref name="klepesta" /> [[NGC 625]] is a dwarf [[irregular galaxy]] of apparent magnitude 11.0 and lying some 12.7 million light years distant. Only 24000 light years in diameter, it is an outlying member of the [[Sculptor Group]]. NGC 625 is thought to have been involved in a collision and is experiencing a burst of [[Active galactic nucleus|active star formation]].<ref>{{cite book  | last = O'Meara  | first = Stephen James  | date = 2011  | title = Deep-Sky Companions: The Secret Deep | publisher = Cambridge University Press | location = Cambridge, United Kingdom  | isbn = 978-0-521-19876-9 |url=https://books.google.com/books?id=S5QIEKns33sC&q=southern+bird+constellations+phoenix&pg=PA40 |pages=40–43}}</ref> [[Robert's Quartet]] (composed of the irregular galaxy [[NGC 87]], and three spiral galaxies [[NGC 88]], [[NGC 89]] and [[NGC 92]]) is a group of four galaxies located around 160 million light-years away which are in the process of colliding and merging. They are within a circle of radius of 1.6 arcmin, corresponding to about 75,000 light-years.<ref>{{cite web|url=http://www.eso.org/outreach/press-rel/pr-2005/phot-34-05.html|title=eso0535&nbsp;— Photo Release: Cosmic Portrait of a Perturbed Family|last=Boffin|first=Henri|date=4 November 2005|publisher=European Southern Observatory|access-date=24 August 2012|url-status=dead|archive-url=https://web.archive.org/web/20081011231649/http://www.eso.org/outreach/press-rel/pr-2005/phot-34-05.html|archive-date=11 October 2008}}</ref> Located in the galaxy ESO 243-49 is [[HLX-1]], an [[intermediate-mass black hole]]—the first one of its kind identified. It is thought to be a remnant of a dwarf galaxy that was absorbed in a [[Interacting galaxy|collision]] with ESO 243-49.{{citation needed|date=May 2020}} Before its discovery, this class of black hole was only hypothesized.<ref>{{cite web|url=http://thebunsenburner.com/news/astronomers-spot-the-very-first-intermediate-mass-black-hole/|title=Astronomers spot the very first intermediate-mass black hole|date=9 July 2012|work=The Bunsen Burner|publisher=T.E. Holdings LLC|access-date=15 August 2013|archive-url=https://web.archive.org/web/20131203012901/http://thebunsenburner.com/news/astronomers-spot-the-very-first-intermediate-mass-black-hole/|archive-date=3 December 2013|url-status=usurped}}</ref>

Lying within the bounds of the constellation is the gigantic [[Phoenix cluster]], which is around 7.3 million light years wide and 5.7 billion light years away, making it one of the most massive [[galaxy cluster]]s. It was first discovered in 2010, and the central galaxy is producing an estimated 740 new stars a year.<ref>{{cite web|url=http://web.mit.edu/newsoffice/2012/cool-luminous-galaxy-cluster-identified-0815.html|title=Most massive and luminous galaxy cluster identified|last=Chu|first=Jennifer |date=15 August 2012 |work=MIT News|publisher= Massachusetts Institute of Technology|access-date=25 August 2012|location=Cambridge, Massachusetts}}</ref> Larger still is [[El Gordo (galaxy cluster)|El Gordo]], or officially ACT-CL J0102-4915, whose discovery was announced in 2012.<ref>{{cite web |url=http://www.nasa.gov/mission_pages/chandra/news/H-12-008.html |title=NASA's Chandra Finds Largest Galaxy Cluster in Early Universe |author=Perrotto, Trent J. |author2=Anderson, Janet |author3=Watzke, Megan |date=10 January 2012 |publisher=NASA |access-date=2 September 2013 |archive-date=1 May 2017 |archive-url=https://web.archive.org/web/20170501103010/https://www.nasa.gov/mission_pages/chandra/news/H-12-008.html |url-status=dead }}</ref> Located around 7.2 billion light years away, it is composed of two subclusters in the process of colliding, resulting in the spewing out of hot gas, seen in X-rays and infrared images.<ref>{{cite web|url=http://chandra.si.edu/photo/2012/elgordo/ |title=El Gordo: NASA's Chandra Finds Largest Galaxy Cluster in Early Universe |author=Chandra X-ray Observatory |date=10 January 2012 |publisher= NASA |access-date=2 September 2013}}</ref>