View source for Laniakea Supercluster

{{Short description|Galaxy supercluster that is home to the Milky Way Galaxy and many more galaxies}}
{{Other uses|Laniakea (disambiguation){{!}}Laniakea}}

{{Infobox galaxy cluster
| name = Laniakea Supercluster
| image = 07-Laniakea (LofE07240).png
| caption = A map of the Laniakea Supercluster and its component galaxy clusters
| epoch = [[Epoch (astronomy)#Julian years and J2000|J2000]]
| constellation = [[Triangulum Australe]] and [[Norma (constellation)|Norma]]<br/>(''[[Great Attractor]]'')
| ra = {{RA|10|32}}
| dec = {{DEC|-46|00}}<br/>
| member_no = 100,000–150,000
| parent = [[Pisces–Cetus Supercluster Complex]]
| major_axis_mpc = {{convert|520|e6ly|Mpc|0|abbr=unit|lk=on}} {{hub|67.80 ± 0.77}}<br/>([[Hubble constant|H<sub>0</sub>]] from [[Planck (satellite)|''Planck'']] 2013)
| minor_axis_mpc = <!-- {{convert|000|Mpc|e6ly|0|abbr=on|lk=on}} {{hub|0.00}} -->
| redshift = 0.0708 (''center'')
| distance = {{convert|250|e6ly|Mpc|0|abbr=unit|lk=on}} {{hub|67.80 ± 0.077}}<br/>(''Great Attractor'')<br/>([[Hubble constant|H<sub>0</sub>]] from [[Planck (spacecraft)|Planck]] 2013)
| mass = 1{{e|17}}<ref>{{cite news | url=http://www.citylab.com/housing/2014/09/the-milky-ways-city-just-got-a-new-name/379502/ | title=The Milky Way's 'City' Just Got a New Name | newspaper=Bloomberg.com | publisher=[[The Atlantic#CityLab|CityLab]] | date=3 September 2014 | access-date=9 September 2014}}</ref>
| luminosity = 
| flux = 
| other_names = Local&nbsp;Supercluster, Laniakea, Laniakea&nbsp;Supercluster, Laniakea&nbsp;Complex
}}

The '''Laniakea Supercluster''' ({{IPAc-en|ˌ|l|ɑː|n|i|.|ə|ˈ|k|eɪ|.|ə}}; [[Hawaiian language|Hawaiian]] for "open skies" or "immense heaven")<ref>{{Cite book|title=Science Encyclopedia|last=Taylor|first=Charles|publisher=Kingfisher|year=2014}}</ref> or the '''Local Supercluster''' ('''LSC''' or '''LS''') is the [[galaxy]] [[supercluster]] that is home to the [[Milky Way]] and approximately 100,000 other nearby galaxies. 

It was defined in September 2014, when a group of astronomers including [[R. Brent Tully]] of the [[University of Hawaiʻi at Mānoa|University of Hawaiʻi]], [[Hélène Courtois]] of the [[University of Lyon]], Yehuda Hoffman of the [[Hebrew University of Jerusalem]], and [[Daniel Pomarède]] of CEA [[Université Paris-Saclay]] published a new way of defining superclusters according to the [[Radial velocity|relative velocities]] of galaxies.<ref name=":0">{{Cite journal|last1=Tully|first1=R. Brent|last2=Courtois|first2=Hélène|last3=Hoffman|first3=Yehuda|last4=Pomarède|first4=Daniel|date=Sep 2014|title=The Laniakea supercluster of galaxies|url=https://www.nature.com/articles/nature13674|journal=Nature|language=en|volume=513|issue=7516|pages=71–73|doi=10.1038/nature13674|pmid=25186900|issn=1476-4687|arxiv=1409.0880|bibcode=2014Natur.513...71T|s2cid=205240232}}</ref><ref>{{Cite journal|last=Tempel|first=Elmo|date=2014-09-01|title=Cosmology: Meet the Laniakea supercluster|journal=Nature|volume=513|issue=7516|pages=41–42|doi=10.1038/513041a|pmid=25186896|bibcode=2014Natur.513...41T|doi-access=free}}</ref> The new definition of the local supercluster subsumes the prior defined [[Virgo Supercluster|Virgo]] and [[Hydra-Centaurus Supercluster]] as appendages, the former being the prior defined local supercluster.<ref name=NRAO-2014-09-03/><ref name= Reuters-2014-09-03/><ref name=Nature-2014-09-03/><ref name="NYT-20140903"/><ref name="SandT-2014-09-03"/>

Follow-up studies suggest that the Laniakea Supercluster is not gravitationally bound. It will disperse rather than continue to maintain itself as an overdensity relative to surrounding areas.<ref name=chon>{{cite journal|bibcode=2015A&A...575L..14C|arxiv=1502.04584|title=On the definition of superclusters|journal=Astronomy & Astrophysics|volume=575|pages=L14|last1=Chon|first1=Gayoung|last2=Böhringer|first2=Hans|last3=Zaroubi|first3=Saleem|year=2015|doi=10.1051/0004-6361/201425591|s2cid=119195010}}</ref>

== Name ==
The name {{lang|haw|laniākea}} ({{IPA|haw|ˈlɐnijaːˈkɛjə|}}) means 'immense heaven' in [[Hawaiian language|Hawaiian]], {{ety||lani|heaven||ākea|spacious, immeasurable}}. The name was suggested by [[Nawaʻa Napoleon]], an associate professor of Hawaiian language at [[Kapiolani Community College]].<ref>{{Cite web|url=https://www.nsf.gov/news/mmg/mmg_disp.jsp?med_id=79249|title=Multimedia Gallery – &#124; NSF – National Science Foundation}}</ref> The name honors [[Polynesian navigation|Polynesian navigators]], who used knowledge of the sky to navigate the [[Pacific Ocean]].<ref>{{Cite web|title=Astronomers define boundaries of our home supercluster and name it Laniakea {{!}} EarthSky.org|url=https://earthsky.org/space/laniakea-is-the-new-name-for-our-home-supercluster-of-galaxies|access-date=2020-09-06|website=earthsky.org|date=3 September 2014|language=en-US}}</ref>

== Characteristics ==
[[File:Nearby Superclusters.webm|thumb|A video showing in 3D Laniakea and other nearby superclusters of galaxies]]
The Laniakea Supercluster encompasses approximately 100,000 galaxies stretched out over {{convert|160|Mpc|e6ly|abbr=unit|lk=on}}. It has the approximate mass of 10<sup>17</sup> solar masses, or 100,000 times that of our galaxy, which is almost the same as that of the [[Horologium Supercluster]].<ref name=":0"/> It consists of four subparts, which were known previously as separate superclusters:

* [[Virgo Supercluster]], the part in which the Milky Way resides.
* [[Hydra–Centaurus Supercluster]]
** the [[Great Attractor]], Laniakea's central gravitational point near [[Norma Cluster|Norma]]
** [[Antlia Wall]], known as [[Hydra Supercluster]]
** [[Centaurus Supercluster]]
* [[Pavo–Indus Supercluster]]
* [[Southern Supercluster]], including [[Fornax Cluster]] (S373), [[Dorado Cluster|Dorado]] and [[Eridanus Cluster|Eridanus]] clouds.<ref>{{cite book |chapter-url=https://link.springer.com/chapter/10.1007/978-1-4613-9356-6_65 |last=Mitra |first=Shyamal |title=The World of Galaxies |chapter=A Study of the Southern Supercluster |date=1989 |publisher=Springer |location=New York, NY. |pages=426–427 |doi=10.1007/978-1-4613-9356-6_65 |isbn=978-1-4613-9358-0 |access-date=23 September 2020 |archive-url=https://web.archive.org/web/20180609021849/https://link.springer.com/chapter/10.1007/978-1-4613-9356-6_65 |archive-date=9 June 2018}}</ref>

The most massive galaxy clusters of the Laniakea Supercluster are [[Virgo Cluster|Virgo]], [[Hydra Cluster|Hydra]], [[Centaurus Cluster|Centaurus]], [[List of Abell clusters|Abell 3565]], [[Abell 3574]], [[Abell 3521]], [[Fornax Cluster|Fornax]], [[Eridanus Cluster|Eridanus]], and [[Norma Cluster|Norma]]. The entire supercluster consists of approximately 300 to 500 known galaxy clusters and groups. The real number may be much larger because some of these are traversing the [[Zone of Avoidance]], an area of the sky that is partially obscured by [[gas]] and [[Cosmic dust|dust]] from the [[Milky Way]] galaxy, making them essentially undetectable.

Superclusters are some of the [[universe]]'s largest structures and have boundaries that are difficult to define, especially from the inside. Within a given supercluster, most galaxy motions will be directed inward, toward the [[center of mass]]. This gravitational focal point, in the case of Laniakea, is called the [[Great Attractor]], and influences the motions of the [[Local Group]] of galaxies, where the Milky Way galaxy resides, and all others throughout the supercluster. Unlike its constituent clusters, Laniakea is not [[gravitational binding energy|gravitationally bound]] and is projected to be torn apart by [[dark energy]].<ref name=Nature-2014-09-03/>

Although the confirmation of the existence of the Laniakea Supercluster emerged in 2014,<ref name=":0"/> early studies in the 1980s already suggested that several of the superclusters then known might be connected. For example, South African astronomer [[Anthony Patrick Fairall|Tony Fairall]] stated in 1988 that redshifts suggested that the Virgo and Hydra–Centaurus superclusters may be connected.<ref>{{cite journal|last=Fairall|first=Anthony Patrick|date=1988|title=A redshift map of the Triangulum Australe-Ara region – Further indication that Centaurus and Pavo are one and the same supercluster|journal=Monthly Notices of the Royal Astronomical Society|volume=230|issue=1|pages=69–77|bibcode=1988MNRAS.230...69F|doi=10.1093/mnras/230.1.69|doi-access=free}}</ref>

== Location ==
[[File:Laniakea.gif|thumb|A map of superclusters within the nearby [[universe]], with Laniakea shown in yellow]]
The neighboring superclusters to the Laniakea Supercluster are the [[Shapley Supercluster]], [[Hercules Supercluster]], [[Coma Supercluster]], and [[Perseus–Pisces Supercluster]]. The edges of the superclusters and Laniakea were not clearly known at the time of Laniakea's definition.<ref name= Reuters-2014-09-03/> Since then, the study of the edges of the supercluster and of structures beyond them has substantially improved.<ref>{{Cite news|work=University of Hawaii News|title=Astronomers map massive structure beyond Laniakea Supercluster {{!}} University of Hawaiʻi System News|url=https://www.hawaii.edu/news/2020/07/10/laniakea-supercluster-mapping/|access-date=2020-09-10|language=en-US}}</ref><ref>{{Cite journal|last1=Pomarède|first1=Daniel|last2=Tully|first2=R. Brent|last3=Graziani|first3=Romain|last4=Courtois|first4=Hélène M.|last5=Hoffman|first5=Yehuda|last6=Lezmy|first6=Jérémy|date=2020-07-01|title=Cosmicflows-3: The South Pole Wall|journal=The Astrophysical Journal|volume=897|issue=2|pages=133|doi=10.3847/1538-4357/ab9952|arxiv=2007.04414|bibcode=2020ApJ...897..133P|s2cid=220425419 |doi-access=free }}</ref>

Laniakea is itself a constituent part of the [[Pisces–Cetus Supercluster Complex]], a [[galaxy filament]].

== See also ==
<!-- Please keep entries in alphabetical order and add a short description [[WP:SEEALSO]] -->
{{div col||colwidth=30em}}
* [[Dipole repeller]]
* [[Galaxy cluster]]
* [[Galaxy filament]]
* [[Illustris project]]
* [[Local Void]] – nearest neighboring void
* [[Supercluster]]
* [[Void (astronomy)]]
* [[List of Abell clusters]]
{{div col end}}
<!-- please keep entries in alphabetical order -->

== References ==
{{reflist|30em|refs=
<ref name=NRAO-2014-09-03>{{cite news |work= National Radio Astronomy Observatory |publisher= ScienceDaily |date= 3 September 2014 |url= https://www.sciencedaily.com/releases/2014/09/140903133319.htm |title= Newly identified galactic supercluster is home to the Milky Way }}</ref>
<ref name= Reuters-2014-09-03>{{cite web |work= Reuters |date= 2014-09-03 |url= https://www.reuters.com/article/us-space-galaxies-idUSKBN0GY2C820140903 |author= Irene Klotz |title= New map shows Milky Way lives in Laniakea galaxy complex }}</ref>
<ref name=Nature-2014-09-03>{{cite news |journal= Nature |url= http://www.nature.com/news/earth-s-new-address-solar-system-milky-way-laniakea-1.15819 |title= Earth's new address: 'Solar System, Milky Way, Laniakea' |author= Elizabeth Gibney |date= 3 September 2014 |doi= 10.1038/nature.2014.15819 }}</ref>
<ref name="NYT-20140903">{{cite news |last=Quenqua |first=Douglas |title=Astronomers Give Name to Network of Galaxies |url=https://www.nytimes.com/2014/09/09/science/space/astronomers-give-name-to-network-of-galaxies.html |date=3 September 2014 |work=[[New York Times]] |access-date=4 September 2014 }}</ref>
<ref name="SandT-2014-09-03">{{cite news |publisher= Sky and Telescope |title= Laniakea: Our Home Supercluster |first= Camille M. |last= Carlisle |date= 3 September 2014 |access-date= 3 September 2014 |url= http://www.skyandtelescope.com/astronomy-news/laniakea-home-supercluster-09032014/ }}</ref>
}}

== Further reading ==
* {{cite journal |title= The Laniakea supercluster of galaxies |author1=R. Brent Tully |author2=Hélène Courtois|author-link2=Hélène Courtois|author3=Yehuda Hoffman |author4=Daniel Pomarède |date= 2 September 2014 |publication-date= 4 September 2014 |journal= Nature |volume= 513 |number= 7516 |pages=71–3 |bibcode= 2014Natur.513...71T |arxiv= 1409.0880 |doi= 10.1038/nature13674 |pmid=25186900|s2cid=205240232 }}
* [http://www.universetoday.com/114304/meet-laniakea-our-home-supercluster/ Meet Laniakea, Our Home Supercluster]

== External links ==
{{Wikiquote}}
* {{icon|file}} Vimeo, [http://vimeo.com/104910552 "Laniakea Supercluster"], Daniel Pomarède, <!-- 1 -->4 September 2014—video representation of the findings of the discovery paper
* {{icon|file}} YouTube, [https://www.youtube.com/watch?v=rENyyRwxpHo "Laniakea: Our Home Supercluster"], Nature Video, 3 September 2014—Redrawing the boundaries of the cosmic map, they redefine our home supercluster and name it Laniakea.
{{Solar System}}
{{Local Group}}
{{2014 in space}}
{{Earth's location}}
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[[Category:Laniakea Supercluster| ]]
[[Category:Astronomical objects discovered in 2014|201409??]]
[[Category:Galaxy superclusters]]