View source for ULAS J1120+0641

{{Short description|One of the most distant quasars known}}
{{Quasar
  | name = ULAS J1120+0641
  | image = [[File:ULAS J1120+0641.jpg|300px]]
  | caption= Composite image of ULAS J1120+0641 created from the [[Sloan Digital Sky Survey]] and the [[UKIRT Infrared Deep Sky Survey]]. The quasar appears as a faint red dot close to the centre.
  | epoch = J2000.0
  | ra = {{RA|11|20|01.48}}
  | dec = {{DEC|+06|41|24.3}}
  | constellation name = [[Leo (constellation)|Leo]]
  | z = {{val|7.085|0.003}}<ref name=mortlock/>
  | dist_ly = {{convert|28.85|Gly|Gpc|abbr=on|lk=on}} <small>([[co-moving distance|co-moving]])</small><ref name="cosmo_calc">{{cite web | title =Ned Wright's Javascript Cosmology Calculator | url = http://www.astro.ucla.edu/~wright/CosmoCalc.html | last =Wright | first =Ned | access-date = 1 July 2011}}</ref><br/>{{convert|12.9|Gly|Gpc|abbr=on|lk=off}} <small>([[Distance measures (cosmology)|light travel distance]])</small>{{citation needed|date=December 2014}}
  | names = {{nobr|ULAS  J112001.48+064124.3}},<ref name=mortlock/> {{nobr|ULAS J1120+0641}}<ref name=SciAm-2011-06-29/>
}}

'''ULAS J1120+0641''' was the most distant known [[quasar]] when discovered in 2011, surpassed in 2017 by [[ULAS J1342+0928]].<ref name="NAT-20171206">{{cite journal |author=Bañados, Eduardo|display-authors=etal|title=An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5 |date=6 December 2017 |journal=[[Nature (journal)|Nature]] |volume=553|issue=7689|pages=473–476|doi=10.1038/nature25180 |pmid=29211709|arxiv=1712.01860 |bibcode=2018Natur.553..473B |s2cid=205263326 }}</ref><ref name="NASA-20171206">{{cite web |last1=Landau |first1=Elizabeth |last2=Bañados |first2=Eduardo |title=Found: Most Distant Black Hole |url=https://www.jpl.nasa.gov/news/news.php?feature=7017 |date=6 December 2017 |work=[[NASA]] |access-date=6 December 2017 }}</ref><ref name="SPC-20171206">{{cite web |last=Choi |first=Charles Q. |title=Oldest Monster Black Hole Ever Found Is 800 Million Times More Massive Than the Sun |url=https://www.space.com/39000-oldest-farthest-monster-black-hole-yet.html |date=6 December 2017 |work=[[Space.com]] |access-date=6 December 2017 }}</ref> ULAS J1120+0641 (at projected [[comoving distance]] of 28.85 billion light-years<ref name=distance group=note/>) was the first quasar discovered beyond a [[redshift]] of z = 7.<ref name=Mortlock-2011-05>{{cite journal |title=Photometry of the z=7.08 quasar ULAS J1120+0641 |author= Steve Warren |author2= Daniel Mortlock |display-authors= etal |journal= Spitzer Proposals |volume=80114 |pages= 80114 |date=May 2011 |bibcode=2011sptz.prop80114W }}</ref> Its discovery was reported in June 2011.<ref name=mortlock/>{{#tag:ref|Various news reports, including those provided by the [[Associated Press]], have stated that it is the brightest object seen so far in the universe.<ref name=atlantic>{{cite news|last=Jackson|first=Nicholas|title=Early Quasar Is Brightest Object Ever Found in the Universe|url=https://www.theatlantic.com/technology/archive/2011/06/early-quasar-is-brightest-object-ever-found-in-the-universe/241294/|access-date=30 June 2011|quote=ULAS J1120+0641 took the brightest object title from another quasar that wasn't formed until about 100 million years later, when the universe was 870 million years old.|newspaper=[[The Atlantic]]|date=30 June 2011}}</ref> Such statements are erroneous, however; other quasars are known to be at least 100 times more luminous.<ref name=Hopkins>{{Cite journal | last1 = Hopkins | first1 = P. F. | last2 = Richards | first2 = G. T. | last3 = Hernquist | first3 = L. | title = An Observational Determination of the Bolometric Quasar Luminosity Function | journal = The Astrophysical Journal | volume = 654 | issue = 2 | pages = 731–753 | year = 2007 | doi = 10.1086/509629|arxiv = astro-ph/0605678 |bibcode = 2007ApJ...654..731H | s2cid = 14363887 }}</ref>|group=note}}

==Discovery==
ULAS J1120+0641 was discovered by the [[UKIRT Infrared Deep Sky Survey]] (UKIDSS), using the [[UK Infrared Telescope]], located in [[Hawaii]].<ref name=Astronomy-2011-06-29>{{cite web |title= Most distant quasar found |author=ESO |date=2011-06-29 |publisher=Astronomy Magazine |url=http://www.astronomy.com/~/link.aspx?_id=ca37f3be-86bd-4a8a-894d-64c8a56b628d |access-date=2011-06-30 }}</ref> The name of the object is derived from UKIDSS Large Area Survey (ULAS), the name of the survey that discovered the quasar, and the location of the quasar in the sky in terms of [[right ascension]] (11h&nbsp;20m) and [[declination]] (+06°&nbsp;41'). This places the quasar in the constellation of [[Leo (constellation)|Leo]], close (on the plane of the sky) to [[σ Leo]]. The quasar was discovered by a telescope that operates at [[infrared]] [[wavelength]]s, which is at longer wavelength and lower energy than [[visible light]]. When the light was originally emitted by ULAS J1120+0641, it was in the [[ultraviolet]], with shorter wavelength and higher energy than visible light. The change in energy and wavelength of the light is due to the [[expanding universe]], which imparts a [[cosmological redshift]] to all light as it travels through the universe.<ref name = bbcnews/>

The team of scientists spent years searching the UKIDSS for a quasar whose  [[Redshift#Highest redshifts|redshift was higher than 6.5]]. ULAS J1120+0641 is even farther away than they hoped for, with a redshift greater than 7.<ref name=wired>{{cite news|last=Brown|first=Mark|title=Infancy of Universe Seen in Brightest Quasar Yet|url=https://www.wired.com/wiredscience/2011/06/brightest-distant-quasar/|publisher=Wired News|access-date=30 June 2011|date=2011-06-30}}</ref>

UKIDSS is a [[near infrared]] [[photometry (astronomy)|photometric]] survey, so the original discovery was only a photometric redshift of <math>z_{phot}>6.5</math>.<ref name = mortlock/> Before announcing their discovery, the team used [[spectroscopy]] on the [[Gemini North Telescope]] and the [[Very Large Telescope]] to obtain a spectroscopic redshift of {{val|7.085|0.003}}.<ref name = mortlock/>

==Description==
[[Image:Artist's rendering ULAS J1120+0641.jpg|thumb|Artist's rendering of ULAS J1120+0641.]]

ULAS J1120+0641 has a measured [[redshift]] of 7.085, which corresponds to a [[comoving distance]] of 28.85 billion [[light-year]]s from [[Earth]].<ref name=distance group=note>This is greater than the estimated age of the light from the most distant observable objects, yet is not in contradiction. See [[Distance measures (cosmology)]] which explains the distance measures used in [[cosmology]].</ref> {{As of|2011|6}}, it is the most distant quasar yet observed.<ref name=bbcnews/>{{update needed|date=July 2024}} The quasar emitted the light observed on Earth today less than 770 million years after the [[Big Bang]], about 13 billion years ago.<ref name=AliciaChang-2011-06-30>{{cite news |author= Alicia Chang |title= Scientists discover brightest, earliest quasar |publisher= [[Associated Press]] |url= https://www.google.com/hostednews/ap/article/ALeqM5hUutbk1jqYTTJQud0iSJk_HX-2Fg?docId=287f3be672eb4f4a8c3dbc61a3720b02 |date= 2011-06-30 |access-date= 2011-07-01}}{{dead link|date=June 2024|bot=medic}}{{cbignore|bot=medic}}</ref> This is 100 million years earlier than light from the most distant previously known quasar.<ref name=wapo>{{cite news|last=Flock|first=Elizabeth|title=Quasar found from dawn of time|url=https://www.washingtonpost.com/blogs/blogpost/post/quasar-found-from-dawn-of-time/2011/06/30/AGs9T4rH_blog.html|access-date=30 June 2011|newspaper=Washington Post|date=30 June 2011}}</ref>

The quasar's [[luminosity]] is estimated at {{val|6.3|e=13}} [[solar luminosity|solar luminosities]]. This energy output is generated by a [[supermassive black hole]] estimated at {{val|2|+1.5|-0.7|e=9}} [[solar mass]]es.<ref name=mortlock/><ref name=SciAm-2011-06-29>{{cite web |title=Brilliant, but Distant: Most Far-Flung Known Quasar Offers Glimpse into Early Universe |author=John Matson |date=2011-06-29 |publisher=[[Scientific American]] |url=http://www.scientificamerican.com/article.cfm?id=farthest-quasar |access-date=2011-06-30 }}</ref> While the black hole powers the quasar, the light does not come from the black hole itself. Daniel Mortlock, lead author of the paper that announced the discovery of ULAS J1120+0641, explained, "The super-massive black hole itself is dark but it has a disc of gas or dust around it that has become so hot that it will outshine an entire galaxy of stars."<ref name =bbcnews/>

==Significance==
The light from ULAS J1120+0641 was emitted before the end of the theoretically-predicted transition of the [[intergalactic medium]] from an electrically neutral to an [[ionized]] state (the [[epoch of reionization]]). Quasars may have been an important energy source in this process, which marked the end of the [[Timeline of the Big Bang#Dark Ages|cosmic Dark Ages]], so observing a quasar from before the transition is of major interest to theoreticians.<ref name=SciAm-2011-06-29/><ref name=willott/> Because of their high ultraviolet luminosity, quasars also are some of the best sources for studying the reionization process.

This is the first time scientists have seen a quasar with such a large fraction of neutral (non-ionized) [[hydrogen]] absorption in its spectrum. Mortlock estimates that 10% to 50% of the hydrogen at the redshift of ULAS J1120+0641 is neutral. The neutral hydrogen fraction in all other quasars seen, even those only 100 million years younger, was typically 1% or less.<ref name=bbcnews>{{cite news|last=Amos|first=Jonathan|title='Monster' driving cosmic beacon|url=https://www.bbc.co.uk/news/science-environment-13964767|access-date=30 June 2011|newspaper=[[BBC News]]|date=30 June 2011}}</ref> The spectrum also lacked any significant indication of [[Big Bang nucleosynthesis|non-BBN]] metals. The combination of the neutral hydrogen reading, and lack of metals is suggestive of the quasar being embedded in a [[protogalaxy]] in the midst of forming, and possibly creating the first [[Population III star]]s for the galaxy, or a pre-protogalaxy core still embedded in the primordial hydrogen fog, predating the Population III stellar population for this galaxy.<ref>{{cite news |publisher= [[Ars Technica]] |url= https://arstechnica.com/science/2012/12/ancient-quasar-imaged-when-the-universe-lacked-heavy-metal/ |title= Ancient quasar imaged when the Universe lacked heavy metal |date= 5 December 2012 |access-date= March 15, 2013 |author= Matthew Francis }}</ref>

The supermassive black hole in ULAS J1120+0641 has a higher mass than was expected. The [[Eddington limit]] sets a maximum rate at which a black hole can grow, so the existence of such a massive black hole so soon after the Big Bang implies that it must have formed with a very high initial mass, through the merging of thousands of smaller black holes, or that the standard model of cosmology requires revision.<ref name=willott>{{Cite journal | last1 = Willott | first1 = C. | title = Cosmology: A monster in the early Universe | journal = Nature | volume = 474 | issue = 7353 | pages = 583–584 | year = 2011 | pmid = 21720357 | doi = 10.1038/474583a|arxiv = 1106.6090 |bibcode = 2011Natur.474..583W | s2cid = 205065580 }}[https://arxiv.org/abs/1106.6090 preprint of this paper]</ref>

==See also==
* [[List of the most distant astronomical objects|List of most distant astronomical objects]]
* [[List of quasars]]
* [[J0313–1806]] − most distant quasar (z=7.64)

== Notes ==
{{reflist|group=note}}

== References ==
{{reflist|colwidth=25em|refs=

<ref name=mortlock>
{{cite journal |title=A luminous quasar at a redshift of z = 7.085 |author=Daniel J. Mortlock |author2=Stephen J. Warren |author3=Bram P. Venemans|display-authors=etal |journal=Nature |volume=474 |issue=7353 |pages=616–619 |date=2011 |doi=10.1038/nature10159|arxiv=1106.6088 |bibcode = 2011Natur.474..616M |pmid=21720366|s2cid=2144362 }}
</ref>

}}

== External links ==
{{Commons category}}
* ESO, [http://www.eso.org/public/images/eso1122b/ "The most distant quasar"] (Image)
* PhysOrg, [http://www.physorg.com/news/2011-06-astronomers-universe-distant-quasar.html "Astronomers find universe's most distant quasar (w/ video)"]

{{Sky|11|20|01.48|+|06|41|24.3|28850000000}}

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{{s-bef|before=[[CFHQS J2329-0301]]}}
{{s-ttl|title=[[List of quasars#Most distant quasars|Most distant quasar]]|years=2011&nbsp;–&nbsp;2017}}
{{s-aft|after=[[ULAS J1342+0928]]}}
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{{Portal bar|Astronomy|Physics}}
{{2011 in space}}

[[Category:Astronomical objects discovered in 2011|20110630]]
[[Category:Leo (constellation)]]
[[Category:Quasars]]