View source for High-velocity galaxy radiation astronomy

'''Editor-In-Chief:''' Henry A. Hoff
[[Image:Irregular galaxy NGC 1427A (captured by the Hubble Space Telescope).jpg|thumb|right|200px|The irregular galaxy NGC 1427A is passing through the Fornax cluster at nearly 600 kilometers per second (400 miles per second). Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA).]]
"The irregular galaxy NGC 1427A is a spectacular example of the resulting stellar rumble. Under the gravitational grasp of a large gang of galaxies, called the Fornax cluster, the small bluish galaxy is plunging headlong into the group at 600 kilometers per second or nearly 400 miles per second."<ref name=Gregg>{{ cite web
|author=M. Gregg
|title=The Impending Destruction of NGC 1427A
|publisher=Hubblesite.org
|location=Baltimore, Maryland USA
|date=3 March 2005
|url=http://hubblesite.org/newscenter/archive/releases/2005/09/image/a/
|accessdate=2016-11-05 }}</ref>

"Galaxy clusters, like the Fornax cluster, contain hundreds or even thousands of individual galaxies. Within the Fornax cluster, there is a considerable amount of gas lying between the galaxies. When the gas within NGC 1427A collides with the Fornax gas, it is compressed to the point that it starts to collapse under its own gravity. This leads to formation of the myriad of new stars seen across NGC 1427A, which give the galaxy an overall arrowhead shape that appears to point in the direction of the galaxy's high-velocity motion."<ref name=Gregg/>
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==Active galaxies==

The majority of active galaxies are very distant and show large Doppler shifts suggesting that active galaxies occurred in the early Universe and, due to cosmic inflation, are receding away from the Milky Way at very high speeds, where Quasars are the furthest active galaxies, some of them being observed at distances 12 billion light years away and Seyfert galaxies are much closer than quasars.<ref name=Goddard>{{cite web |url=http://imagine.gsfc.nasa.gov/docs/science/know_l1/active_galaxies.html |title=Active Galaxies and Quasars |publisher=NASA/Goddard Space Flight Center (GSFC) |accessdate=21 November 2013}}</ref><ref name=Halliday>{{cite journal |title=Advances in Astronomy Seyfert Galaxies and Quasars |journal=Journal of the Royal Astronomical Society of Canada |first=Ian |last=Halliday |volume=63 |page=91 |year=1969 |bibcode=1969JRASC..63...91H}}</ref>

==Galaxy harassment==

Galaxy harassment is a type of interaction between a low-luminosity galaxy and a brighter one that takes place within rich galaxy clusters, such as the Virgo Cluster and Coma Cluster, where galaxies are moving at high relative speeds and suffering frequent encounters with other systems of the cluster by the high galactic density of the latter, where computer simulations suggest the interactions convert the affected galaxy disks into disturbed barred spiral galaxies and produce starbursts followed by, if more encounters occur, loss of angular momentum and heating of their gas resulting in the conversion of (late type) low-luminosity spiral galaxies into dwarf spheroidals and dwarf ellipticals.<ref>[http://supernova.lbl.gov/~evlinder/umass/sumold/nk/harass.html Galaxy Harassment]</ref>

==Quasars==
[[Image:SDSS image of quasar 3C273.jpg|thumb|left|250px|Sloan Digital Sky Survey (SDSS) image of quasar 3C 273, illustrating the object's star-like appearance. The quasar's jet can be seen extending downward and to the right from the quasar. Credit: Sloan Digital Sky Survey.]]
[[Image:Quasar viewed from Hubble.jpg|thumb|right|250px|Hubble Space Telescope images of quasar 3C 273. At right, a coronagraph is used to block the quasar's light, making it easier to detect the surrounding host galaxy. Credit: WFPC2 image: NASA and J. Bahcall (IAS). Credit for ACS image: NASA, A. Martel (JHU), H. Ford (JHU), M. Clampin (STScI), G. Hartig (STScI), G. Illingworth (UCO/Lick Observatory), the ACS Science Team and ESA.]]
[[Image:UZC J224030.2+032131.jpg|thumb|left|250px|Picture shows a cosmic mirage known as the Einstein Cross. Four apparent images are actually from the same quasar. Credit: ESA/Hubble & NASA.]]
[[Image:MUSE spies accreting giant structure around a quasar.tif|thumb|right|250px|Cloud of gas around the distant quasar SDSS J102009.99+104002.7, taken by Multi-unit spectroscopic explorer (MUSE).<ref>{{cite web|title=MUSE spies accreting giant structure around a quasar|url=http://www.eso.org/public/images/potw1747a/|website=www.eso.org|accessdate=20 November 2017}}</ref> Credit: ESO/Arrigoni Battaia ''et al''.]]
'''Def.''' an "extragalactic object, starlike in appearance,<ref name=QuasarWikt>{{ cite web
|author=[[wikt:User:Anemos|Anemos]]
|title=quasar
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|date=6 March 2006
|url=https://en.wiktionary.org/wiki/quasar
|accessdate=1 June 2019 }}</ref> that [is among] the most luminous and [(putatively)] the most distant objects in the universe"<ref name=QuasarWikt/> is called a '''quasar'''.

The power radiated by quasars is enormous: the most powerful quasars have luminosities thousands of times greater than a galaxy such as the [[Milky Way]].<ref>{{cite journal |last1=Wu |first1=Xue-Bing, ''et al.'' |title=An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30 |journal=Nature |date=2015 |volume=518 |issue=7540 |pages=512–5 |doi=10.1038/nature14241 |pmid=25719667 |arxiv = 1502.07418 |bibcode = 2015Natur.518..512W }}</ref>

High-resolution images of quasars, particularly from the Hubble Space Telescope, have demonstrated that quasars occur in the centers of galaxies, and that some host-galaxies are strongly interacting or merging galaxies.<ref>{{cite journal |last1=Bahcall |first1=J. N., ''et al.'' |title=Hubble Space Telescope Images of a Sample of 20 Nearby Luminous Quasars |journal=The Astrophysical Journal |date=1997 |volume=479 |issue=2 |pages=642–658 |doi=10.1086/303926 |arxiv = astro-ph/9611163 |bibcode = 1997ApJ...479..642B}}</ref>

The peak epoch of quasar activity was approximately 10 billion years ago.<ref>{{cite journal |last1=Schmidt |first1=Maarten |last2=Schneider |first2=Donald |last3=Gunn |first3=James |title=Spectroscopic CCD Surveys for Quasars at Large Redshift.IV.Evolution of the Luminosity Function from Quasars Detected by Their Lyman-Alpha Emission|journal=The Astronomical Journal|date=1995 |volume=110 |page=68 |doi=10.1086/117497 |bibcode = 1995AJ....110...68S}}</ref> As of 2017, the most distant known quasar is ULAS J1342+0928 at redshift ''z'' = 7.54; light observed from this quasar was emitted when the universe was only 690 million years old. The supermassive black hole in this quasar, estimated at 800 million solar masses, is the most distant black hole identified to date.<ref name="NAT-20171206">{{cite journal |author=Bañados, Eduardo, ''et al.''|title=An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5 |date=6 March 2018|journal=Nature |volume=553 |issue=7689 |pages=473–476 |doi=10.1038/nature25180 |pmid=29211709 |arxiv=1712.01860 |bibcode=2018Natur.553..473B }}</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 |accessdate=6 December 2017 }}</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]] |accessdate=6 December 2017 }}</ref>

"So far, the clumsily long name 'quasi-stellar radio sources' is used to describe these objects. Because the nature of these objects is entirely unknown, it is hard to prepare a short, appropriate nomenclature for them so that their essential properties are obvious from their name. For convenience, the abbreviated form 'quasar' will be used throughout this paper."<ref>{{cite journal |last1=Chiu |first1=Hong-Yee |title=Gravitational collapse |journal=Physics Today |volume=17 |issue=5 |page=21 |doi=10.1063/1.3051610 |year=1964 }}</ref>
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==Blazars==
[[Image:SDSS Mrk 421.jpg|thumb|right|250px|Sloan Digital Sky Survey image is of blazar Markarian 421, illustrating the bright nucleus and elliptical host galaxy. Credit: Sloan Digital Sky Survey.]]
'''Def.''' a "very compact quasar, associated with [a supermassive black hole at the center]<ref name=BlazarWikt1>{{ cite web
|author=[[wikt:User:70.55.84.14|70.55.84.14]]
|title=blazar
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|date=20 June 2008
|url=https://en.wiktionary.org/wiki/blazar
|accessdate=1 June 2019 }}</ref> of an active galaxy"<ref name=BlazarWikt2>{{ cite web
|author=[[wikt:User:-sche|-sche]]
|title=blazar
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|date=26 October 2015
|url=https://en.wiktionary.org/wiki/blazar
|accessdate=1 June 2019 }}</ref> or an "object which is either [an optically violent variable quasar or a BL Lac object]<ref name=BlazarWikt>{{ cite web
|author=[[wikt:User:Długosz|Długosz]]
|title=blazar
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|date=29 June 2004
|url=https://en.wiktionary.org/wiki/blazar
|accessdate=1 June 2019 }}</ref> or which has properties of both"<ref name=BlazarWikt2/> is called a '''blazar'''.

Relativistic beaming of electromagnetic radiation from the jet makes blazars appear much brighter than they would be if the jet were pointed in a direction away from the Earth.<ref>{{cite journal |last1=Urry |first1=C. M. |last2=Padovani |first2=P. |title=Unified Schemes for Radio-Loud Active Galactic Nuclei |journal=Publications of the Astronomical Society of the Pacific |date=1995 |volume=107 |page=803 |doi=10.1086/133630 |bibcode=1995PASP..107..803U|arxiv=astro-ph/9506063 }}</ref>

In visible-wavelength images, most blazars appear compact and pointlike, but high-resolution images reveal that they are located at the centers of elliptical galaxies.<ref>{{cite journal |last1=Urry |first1=C. M. |last2=Scarpa |first2=R. |last3=O'Dowd |first3=M. |last4=Falomo |first4=R. |last5=Pesce |first5=J. E. |last6=Treves |first6=A. |title=The Hubble Space Telescope Survey of BL Lacertae Objects. II. Host Galaxies |journal=The Astrophysical Journal |date=2000 |volume=532 |issue=2 |page=816 |doi=10.1086/308616 |bibcode=2000ApJ...532..816U|arxiv=astro-ph/9911109 }}</ref>

In July 2018, the IceCube Neutrino Observatory announced that they have traced a neutrino that hit their Antarctica-based detector in September 2017 back to its point of origin in a blazar 3.7 billion light-years away, which is the first time that a neutrino detector has been used to locate an object in space.<ref name="NYT-2018">{{cite news |last=Overbye |first=Dennis |title=It Came From a Black Hole, and Landed in Antarctica - For the first time, astronomers followed cosmic neutrinos into the fire-spitting heart of a supermassive blazar. |url=https://www.nytimes.com/2018/07/12/science/space-neutrinos-blazar.html |date=12 July 2018 |work=The New York Times |accessdate=13 July 2018 }}</ref><ref name="Guardian-2018">{{cite web |title=Neutrino that struck Antarctica traced to galaxy 3.7bn light years away |url=https://www.theguardian.com/science/2018/jul/12/neutrino-that-struck-antarctica-traced-to-galaxy-37bn-light-years-away |work=The Guardian |date=12 July 2018 |accessdate=12 July 2018 }}</ref><ref name="BBC-2018">{{cite web |title=Source of cosmic 'ghost' particle revealed |url=https://www.bbc.co.uk/news/science-environment-44786125y |work=BBC |date=12 July 2018 |accessdate=12 July 2018 }}</ref>
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==BL Lacertae objects==
[[Image:fig1553.jpg|thumb|right|250px|The optical spectrum is for the BL Lac object PG 1553+11. Credit: [[w:user:Rfalomo|Rfalomo]].]]
[[Image:H0323bl2.gif|thumb|left|250px|The BL Lac object H 0323+022 (z=0.147) is imaged at ESO NTT (R filter). The host galaxy and close companions are visible. Credit: Renato Falomo.]]
'''Def.''' "a type of active galaxy with an active galactic nucleus (AGN), named after its prototype, BL Lacertae"<ref name=BLLacertaeWikt>{{ cite web
|author=[[wikt:User:Mutante|Mutante]]
|title=BL Lacertae object
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|date=5 December 2010
|url=https://en.wiktionary.org/wiki/BL_Lac_object
|accessdate=1 June 2019 }}</ref> is called a '''BL Lac object''', or '''BL Lacertae object'''.

In contrast to other types of active galactic nuclei, BL Lacs are characterized by rapid and large-amplitude flux variability and significant optical polarization.<ref>{{cite journal|last2=Giommi|first2=Paolo|date=15 December 1995|title=A Sample-Oriented Catalogue of BL Lacertae Objects|url=http://ned.ipac.caltech.edu/level5/Padovani/Padovani_contents.html|journal=Monthly Notices of the Royal Astronomical Society|volume=277|issue=4|pages=1477–1490|arxiv=astro-ph/9511065v1|bibcode=1995MNRAS.277.1477P|doi=10.1093/mnras/277.4.1477|first1=Paolo|last1=Padovani }}</ref> Because of these properties, the prototype of the class (BL Lacertae, BL Lac) was originally thought to be a variable star, but when compared to the more luminous active nuclei (quasars) with strong emission lines, BL Lac objects have spectra dominated by a relatively featureless non-thermal emission continuum over the entire electromagnetic range.<ref name="Falomo">{{Cite journal|last=Falomo|first=Renato|year=2014|title=An Optical View of BL Lacertae Objects|url=https://arxiv.org/pdf/1407.7615.pdf|journal=The Astronomy and Astrophysics Review|volume=|pages=44|via=|doi=10.1007/s00159-014-0073-z|arxiv=1407.7615|bibcode=2014A&ARv..22...73F}}</ref> This lack of spectral lines historically hindered BL Lac's identification of their nature and proved to be a hurdle in the determination of their distance.<ref name="Falomo" />

All known BL Lacs are associated with core dominated radio sources, many of them exhibiting superluminal motion.<ref>{{cite journal|date=24 April 2008|title=The inner jet of an active galactic nucleus as revealed by a radio-to-gamma-ray outburst|journal=Nature|volume=452|issue=7190|pages=966–969|bibcode=2008Natur.452..966M|doi=10.1038/nature06895|first1=A P|last1=Marscher|PMID=18432239|display-authors=etal|url=https://deepblue.lib.umich.edu/bitstream/2027.42/62749/1/nature06895.pdf}}</ref>

OVV quasars are generally more luminous and have stronger emission lines than BL Lac objects.<ref>{{Cite journal|last=Urry|first=Megan|year=1995|title=Unified Schemes for Radio-Loud Active Galactic Nuclei|journal=Publications of the Astronomical Society of the Pacific|volume=|pages=|bibcode=1995PASP..107..803U|doi=10.1086/133630|arxiv=astro-ph/9506063}}</ref>
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==Seyfert galaxies==
[[Image:A spiral snowflake.jpg|thumb|right|250px|NGC 6814 is a Type I Seyfert galaxy with a highly variable source of X-ray radiation.<ref>{{cite web|title=A spiral snowflake|url=http://spacetelescope.org/images/potw1619a/|website=spacetelescope.org|accessdate=9 May 2016}}</ref> Credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt (Geckzilla).]]
[[Image:Messier 94.jpg|thumb|left|250px|Messier 94 is a galaxy with a Seyfert-like low-ionization nuclear emission-line region (LINER) nucleus. Credit: R Jay Gabany (Blackbird Obs.).]]
[[Image:Hubble Interacting Galaxy NGC 7469 (2008-04-24).jpg|left|thumb|250px|NGC 7469 (upper right) is a Type 1.2 Seyfert galaxy, IC 5283 is center left, by Hubble Space Telescope. Credit: NASA/JPL-Caltech.{{tlx|free media}}]]
[[Image:NGC 1275 Hubble.jpg|thumb|right|250px|NGC 1275 is a type 1.5 Seyfert galaxy Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration.]]
[[Image:Phot-08a-99-hires.jpg|right|thumb|250px|NGC 1365 is a Type 1.8 Seyfert galaxy. Credit: European Southern Observatory (ESO).{{tlx|free media}}]]
[[Image:NGC1161 - SDSS DR14.jpg|left|thumb|250px|NGC 1161 is a Type 1.9 Seyfert galaxy. Credit: Sloan Digital Sky Survey (SDSS).{{tlx|free media}}]]
[[Image:circinus.galaxy.750pix.jpg|thumb|right|250px|The Circinus Galaxy is a Type II Seyfert galaxy. Credit: NASA, Andrew S. Wilson (University of Maryland); Patrick L. Shopbell (Caltech); Chris Simpson (Subaru Telescope); Thaisa Storchi-Bergmann and F. K. B. Barbosa (UFRGS, Brazil); and Martin J. Ward (University of Leicester, U.K.).]]
Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars, and have quasar-like nuclei (very luminous, distant and bright sources of electromagnetic radiation) with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines,<ref name=Peterson1997>{{cite book |url=http://ned.ipac.caltech.edu/level5/Cambridge/frames.html |title=An Introduction to Active Galactic Nuclei |publisher=Cambridge University Press |first=Bradley M. |last=Peterson |year=1997 |isbn=978-0-521-47911-0}}</ref> but unlike quasars, their host galaxies are clearly detectable.<ref name=Bulgaria>{{cite web |url=http://www.astro.bas.bg/~petrov/galaxies_files/agn.html |title=Active Galaxy Nuclei |publisher=Bulgarian Academy of Sciences/Institute of Astronomy |editor-first=G. T. |editor-last=Petrov |year=2004 |accessdate=9 December 2013}}</ref>

Seyfert galaxies account for about 10% of all galaxies.<ref name=Maiolino>{{cite journal |title=Low-Luminosity and Obscured Seyfert Nuclei in Nearby Galaxies |journal=The Astrophysical Journal |first1=R. |last1=Maiolino |first2=G. H. |last2=Rieke |volume=454 |pages=95–105 |year=1995 |bibcode=1995ApJ...454...95M |doi=10.1086/176468}}</ref>

Seen in visible light, most Seyfert galaxies look like normal spiral galaxies, but when studied under other wavelengths, it becomes clear that the luminosity of their cores is of comparable intensity to the luminosity of whole galaxies the size of the [[Milky Way]].<ref name=Soper>{{cite web |url=http://zebu.uoregon.edu/~soper/ActiveGalxy/seyfert.html |title=Seyfert Galaxies |publisher=University of Oregon |first=D. E. |last=Soper |accessdate=11 October 2013 |deadurl=yes |archiveurl=https://web.archive.org/web/20131023055713/http://zebu.uoregon.edu/~soper/ActiveGalxy/seyfert.html |archivedate=23 October 2013 |df=dmy-all }}</ref>

Seyfert galaxies are named after Carl Keenan Seyfert, who first described this class in 1943.<ref name=Seyfert>{{cite journal |title=Nuclear Emission in Spiral Nebulae |journal=The Astrophysical Journal |first=Carl K. |last=Seyfert |volume=97 |pages=28–40 |year=1943 |doi=10.1086/144488 |bibcode=1943ApJ....97...28S}}</ref>

Very few Seyfert galaxies are ellipticals, most of them being spiral or barred spiral galaxies.<ref name=Adams>{{cite journal |title=A Survey of the Seyfert Galaxies Based on Large-Scale Image-Tube Plate |journal=The Astrophysical Journal Supplement |first=Thomas F. |last=Adams |volume=33 |pages=19–34 |year=1977 |bibcode=1977ApJS...33...19A |doi=10.1086/190416}}</ref>

A simple division into types I and II has been devised, with the classes depending on the relative width of their emission lines.<ref name=Weedman1973>{{cite journal |title=A Photometric Study of Markarian Galaxies |journal=The Astrophysical Journal |first=D. W. |last=Weedman |volume=183 |pages=29–40 |year=1973 |bibcode=1973ApJ...183...29W |doi=10.1086/152205}}</ref>

It has been later noticed that some Seyfert nuclei show intermediate properties, resulting in their being further subclassified into types 1.2, 1.5, 1.8 and 1.9.<ref name=Osterbrock1976>{{cite journal |title=NGC 4151 and Markarian 6: Two intermediate-type Seyfert galaxies |journal=Monthly Notices of the Royal Astronomical Society |first1=D. E. |last1=Osterbrock |first2=A. T. |last2=Koski |volume=176 |pages=61–66 |year=1976 |bibcode=1976MNRAS.176P..61O|doi=10.1093/mnras/176.1.61p }}</ref>
<ref name=Osterbrock1993>{{cite journal |title=Spectroscopic study of the CfA sample of Seyfert galaxies |journal=The Astrophysical Journal |first1=D. E. |last1=Osterbrock |first2=A. |last2=Martel |volume=414 |issue=2 |pages=552–562 |year=1993 |bibcode=1993ApJ...414..552O |doi=10.1086/173102}}</ref>

Several dozen galaxies exhibiting the Seyfert phenomenon exist in the close vicinity (≈27 Mpc) of our own galaxy.<ref name=Maiolino /> Seyfert galaxies form a substantial fraction of the galaxies appearing in the Markarian catalog, a list of galaxies displaying an ultraviolet excess in their nuclei.<ref name=SeyfertList>{{cite web |url=http://www.pa.uky.edu/~shlosman/gals/SEYFERT/ |title=Seyfert Galaxies |publisher=University of Kentucky |first=I. |last=Shlosman |date=6 May 1999 |accessdate=30 October 2013}}</ref>

In a typical Seyfert galaxy, the nuclear source emits at visible wavelengths an amount of radiation comparable to that of the whole galaxy's constituent stars, while in a quasar, the nuclear source is brighter than the constituent stars by at least a factor of 100.<ref name=Peterson1997/><ref name=Popping>{{cite web |url=http://www.astro.rug.nl/~gpopp/projects/agnhostgalaxies.pdf |title=AGN host galaxies and their environment |publisher=University of Groningen |first=Gergö |last=Popping |date=18 July 2008 |accessdate=9 December 2013}}</ref>

Type&nbsp;I Seyferts are very bright sources of ultraviolet light and X-rays in addition to the visible light coming from their cores, with two sets of emission lines on their spectra: narrow lines with widths (measured in velocity units) of several hundred km/s, and broad lines with widths up to 10<sup>4</sup> km/s.<ref name=Armitage>{{cite web |url=http://jila.colorado.edu/~pja/astr3830/lecture27.pdf |title=Astrophysics 2, lecture 27: Active galaxies - the Unified Model |work=ASTR 3830 Lecture Notes |publisher=University of Colorado Boulder |last=Armitage |first=Phil |year=2004 |accessdate=10 November 2013}}</ref>

The broad line emission region, R<sub>BLR</sub>, can be estimated from the time delay corresponding to the time taken by light to travel from the continuum source to the line-emitting gas.<ref name=Massi>{{cite web |url=http://www3.mpifr-bonn.mpg.de/staff/mmassi/QUASARS1small.pdf |title=Active Galaxies |publisher=Max Planck Institute for Radio Astronomy |first=M. |last=Massi |accessdate=10 November 2013}}</ref>

Type II Seyfert galaxies have the characteristic bright core, as well as appearing bright when viewed at infrared wavelengths.<ref name=Morgan>{{cite web |url=http://www.uni.edu/morgans/astro/course/Notes/section3/new13.html |title=Distant and Weird Galaxies |work=Astronomy Course Notes and Supplementary Material |publisher=University of Northern Iowa |first=Siobahn |last=Morgan |accessdate=10 October 2013}}</ref> Their spectra contain narrow lines associated with forbidden transitions, and broad lines associated with allowed strong dipole or intercombination transitions.<ref name=Pradhan>{{cite book |title=Atomic Astrophysics and Spectroscopy |publisher=Cambridge University Press |first1=Anil K. |last1=Pradhan |first2=Sultana N. |last2=Nahar |pages=278–304 |year=2011 |isbn=978-0-521-82536-8}}</ref>

The notations Seyfert&nbsp;1.5, 1.8 and 1.9, the subclasses are based on the optical appearance of the spectrum, with the numerically larger subclasses having weaker broad-line components relative to the narrow lines.<ref name=Osterbrock1981>{{cite journal |title=Seyfert galaxies with weak broad H alpha emission lines |journal=The Astrophysical Journal |first1=D. E. |last1=Osterbrock |volume=249 |pages=462–470 |year=1981 |bibcode=1981ApJ...249..462O |doi=10.1086/159306}}</ref>

In Type&nbsp;1.5, the strength of the Hα and Hβ lines are comparable.<ref name=Caltech>{{cite web |url=http://ned.ipac.caltech.edu/level5/Glossary/Essay_seyfert.html |title=Seyfert galaxies |publisher=California Institute of Technology |accessdate=10 October 2013}}</ref>

The narrow line Seyfert&nbsp;I galaxies (NLSy1) have been subject to extensive research in recent years.<ref name=Osterbrock1985>{{cite journal |title=The spectra of narrow-line Seyfert 1 galaxies |journal=The Astrophysical Journal |first1=D. E. |last1=Osterbrock |first2=R. W. |last2=Pogge |volume=297 |pages=166–176 |year=1985 |bibcode=1985ApJ...297..166O |doi=10.1086/163513}}</ref>
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==Narrow Line Seyfert galaxies==
[[Image:NGC_4051_hst_11661_G547.png|right|thumb|250px|This is a Hubble image of NGC 4051. Credit: [[c:user:Fabian RRRR|Fabian RRRR]].{{tlx|free media}}]]
[[Image:NGC4051 Goran Nilsson & The Liverpool Telescope.jpg|thumb|left|250px|Red/Green/Blue image is of the galaxy NGC 4051 by the earthbound Liverpool Telescope. Credit: [[c:user:Goranen|Göran Nilsson & The Liverpool Telescope]].{{tlx|free media}}]]
[[Image:NGC 4051 GALEX WikiSky.jpg|thumb|right|250px|NGC 4051 is imaged by GALEX. Credit: NASA, GALEX, WikiSky.{{tlx|free media}}]]
[[Image:Quasar HE0450-2958.jpg|thumb|left|250px|Quasar HE0450-2958 is imaged by the Hubble Space Telescope near the center. Credit: NASA, ESA, ESO, F. Courbin (Ecole Polytechnique Federale de Lausanne, Switzerland) and P. Magain (Universite de Liege, Belgium).]]
[[Image:The Quasar Without a Home.jpg|thumb|right|250px|The "quasar without a home" is shown. Credit: ESO.]]
NGC 4051 is an intermediate spiral galaxy in the constellation of Ursa Major.<ref name="ned">{{cite web
    | title=Nasa/Ipac Extragalactic Database
    | url=http://nedwww.ipac.caltech.edu/
    | accessdate=2006-11-27 }}</ref> It was discovered on 6 February 1788 by John Herschel.<ref name=cseligman>{{cite web|title=New General Catalog Objects: NGC 4050 - 4099|url=http://cseligman.com/text/atlas/ngc40a.htm#4051|website=cseligman.com|accessdate=9 November 2017}}</ref>

NGC 4051, a narrow-line Seyfert 1 galaxy, contains a supermassive black hole with a mass of 1.73 million solar masses.<ref name=smbh>{{cite journal|title=A revised broad-line region radius and black hole mass for the narrow-line Seyfert 1 NGC 4051|journal=The Astrophysical Journal|volume=702|issue=2|pages=1353–1366|doi=10.1088/0004-637X/702/2/1353|year=2009|last1=Denney|first1=K. D.|last2=Watson|first2=L. C.|last3=Peterson|first3=B. M.|last4=Pogge|first4=R. W.|last5=Atlee|first5=D. W.|last6=Bentz|first6=M. C.|last7=Bird|first7=J. C.|last8=Brokofsky|first8=D. J.|last9=Comins|first9=M. L.|last10=Dietrich|first10=M.|last11=Doroshenko|first11=V. T.|last12=Eastman|first12=J. D.|last13=Efimov|first13=Y. S.|last14=Gaskell|first14=C. M.|last15=Hedrick|first15=C. H.|last16=Klimanov|first16=S. A.|last17=Klimek|first17=E. S.|last18=Kruse|first18=A. K.|last19=Lamb|first19=J. B.|last20=Leighly|first20=K.|last21=Minezaki|first21=T.|last22=Nazarov|first22=S. V.|last23=Petersen|first23=E. A.|last24=Peterson|first24=P.|last25=Poindexter|first25=S.|last26=Schlesinger|first26=Y.|last27=Sakata|first27=K. J.|last28=Sergeev|first28=S. G.|last29=Tobin|first29=J. J.|last30=Unterborn|first30=C.|displayauthors=29|bibcode=2009ApJ...702.1353D|arxiv=0904.0251 }}</ref> This galaxy was studied by the Multicolor Active Galactic Nuclei Monitoring 2m telescope.<ref>{{cite journal|title=Reverberation Measurements of the Inner Radius of the Dust Torus in Nearby Seyfert 1 Galaxies|last1=Suganuma|first1=Masahiro|last2=Yoshii|first2=Yuzuru|last3=Kobayashi|first3=Yukiyasu|last4=Minezaki|first4=Takeo|last5=Enya|first5=Keigo|last6=Tomita|first6=Hiroyuki|last7=Aoki|first7=Tsutomu|last8=Koshida|first8=Shintaro|last9=Peterson|first9=Bruce A.|journal=The Astrophysical Journal|issn=0004-637X|volume=639|issue=1|date=2006|pages=46–63|doi=10.1086/499326
|arxiv=astro-ph/0511697|bibcode=2006ApJ...639...46S}}</ref> Several supernovae have been discovered in NGC 4051: SN 1983I, SN 2010br, and SN 2003ie.<ref name=SIMBAD>{{cite web|title=NGC 4051|url=http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+4051&submit=SIMBAD+search|accessdate=9 November 2017}}</ref>

The galaxy is a Seyfert galaxy that emits bright X-rays. However, in early 1998 the X-ray emission ceased as observed in by the Beppo-SAX satellite.<ref>{{cite journal|date=1 August 1998|title=Now you se it ...|journal=New Scientist|issue=2145|page=23}}</ref>

NGC 4051 is a member of the Ursa Major Cluster.<ref>{{Cite journal|last=Tully|first=R. Brent|last2=Verheijen|first2=Marc A. W.|last3=Pierce|first3=Michael J.|last4=Huang|first4=Jia-Sheng|last5=Wainscoat|first5=Richard J.|date=December 1996|title=The Ursa Major Cluster of Galaxies.I.Cluster Definition and Photometric Data|journal=The Astronomical Journal|language=en|volume=112|pages=2471|doi=10.1086/118196|issn=0004-6256|arxiv=astro-ph/9608124|bibcode=1996AJ....112.2471T}}</ref><ref name="fouqueetal1992">{{cite journal
  | author=P. Fouque, E. Gourgoulhon, P. Chamaraux, G. Paturel
  | title=Groups of galaxies within 80 Mpc. II - The catalogue of groups and group members
  | journal=Astronomy and Astrophysics Supplement
  | date=1992
  | volume=93
  | pages=211–233
  | bibcode=1992A&AS...93..211F
  | last2=Gourgoulhon
  | last3=Chamaraux
  | last4=Paturel}}</ref><ref>{{Cite web|url=http://www.atlasoftheuniverse.com/galgrps/uma.html|title=The Ursa Major Groups|website=www.atlasoftheuniverse.com|access-date=2018-04-20}}</ref>

The second image down on the left is a quasar near the center of the image with no obvious host galaxy seen, but near the top of the image is a strongly disturbed and star-forming galaxy, the Starburst galaxy, and near the quasar is a blob of gas that is apparently being ionized by the quasar's radiation.<ref name=magain>Magain, P. et al. (2005), [http://adsabs.harvard.edu/abs/2005Natur.437..381M  Discovery of a bright quasar without a massive host galaxy], ''Nature'', '''437''', 381</ref>

"One might suggest that the host galaxy has disappeared from our view as a result of the collision [which formed the disturbed galaxy], but it is hard to imagine how the complete disruption of a galaxy could happen."<ref name=magain/>

A three-body kick to a bright quasar out of its galaxy during a merger is one theory.<ref>Hoffman, L. and Loeb, A. (2005), [https://arxiv.org/abs/astro-ph/0511242 Three-Body Kick to a Bright Quasar out of Its Galaxy During a Merger],  arXiv:astro-ph/0511242</ref>

Possible evidence for the ejection of a supermassive black hole from an ongoing merger of galaxies is presented.<ref>Haehnelt, M. et al. (2005), [https://arxiv.org/abs/astro-ph/0511245  Possible evidence for the ejection of a supermassive black hole from an ongoing merger of galaxies], arXiv:astro-ph/0511245</ref>

The two main arguments against the ejection hypothesis were:<ref name=merritt2006>{{cite journal|last=Merritt|first=David, ''et al.''|title=The nature of the HE0450-2958 system|journal=Monthly Notices of the Royal Astronomical Society|date=April 2006|volume=367|pages=1746–1750|doi=10.1111/j.1365-2966.2006.10093.x |arxiv = astro-ph/0511315 |bibcode = 2006MNRAS.367.1746M }}</ref>
# The quasar spectrum reveals it to be a narrow-line Seyfert 1 galaxy. NLS1's are believed to have abnormally small black holes; since black hole size is strongly correlated with galaxy size, the host galaxy of the quasar should also be abnormally small, explaining why it had not been detected by Magain et al.
# The quasar spectrum also reveals the presence of a classic, narrow emission line region (NLR). The gas producing the narrow lines lies roughly a thousand light-years from the black hole, and such gas could not remain bound to the black hole following a kick large enough to remove it from its host galaxy.

The "naked" quasar is in fact a perfectly normal, narrow-line Seyfert galaxy that happened to lie close on the sky to a disturbed galaxy.<ref name=merritt2006/>

A more careful attempt to find the quasar's host galaxy concluded that it was impossible to rule out the presence of a galaxy given the confusing light from the quasar.<ref>Kim, M. et al. (2006), [http://adsabs.harvard.edu/abs/2007ApJ...658..107K  The Host Galaxy of the Quasar HE 0450-2958], ''The Astrophysical Journal'', '''658''', 107</ref>

The X-ray emission observed from the quasar has been used to estimate the mass of the black hole confirming a small mass for the black hole, implying an even fainter host galaxy than predicted<ref name=merritt2006/>.<ref>Zhou, X.-L. et al. (2007), [http://adsabs.harvard.edu/abs/2007AJ....133..432Z  X-Ray Properties of the Quasar HE 0450-2958], ''The Astronomical Journal'', '''133''', 432</ref>

Radio emission detected from the quasar may indicate ongoing star formation, which "contradicts any suggestion that this is a 'naked' quasar'".<ref>Feain, I. et al. (2007), [http://adsabs.harvard.edu/abs/2007ApJ...662..872F  Dressing a Naked Quasar: Star Formation and Active Galactic Nucleus Feedback in HE 0450-2958], ''The Astrophysical Journal'', '''662''', 872</ref>

Quasar induced galaxy formation may be a new paradigm.<ref>Elbaz.D. et al. (2009) [http://www.aanda.org/10.1051/0004-6361/200912848/pdf Quasar induced galaxy formation: a new paradigm?] Astronomy & Astrophysics  '''507''', 1359–1374</ref>
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==A1689-zD1==
[[Image:A1689-zD1.jpg|right|thumb|300px|Location of A1689-zD1 in infrared and visible light by Hubble Space Telescope and Spitzer Space Telescope. Credit: NASA, ESA, L. Bradley (Johns Hopkins University), R. Bouwens (University of California in Santa Cruz); H. Ford (Johns Hopkins University) and G. Illingworth (University of California in Santa Cruz).{{tlx|free media}}]]
A1689-zD1 is a galaxy in the Virgo constellation cluster. It was a candidate for the most distant and therefore earliest observed galaxy discovered, based on a photometric redshift.<ref name="nasa">{{cite web
  | title = Astronomers Eye Ultra-Young, Bright Galaxy in Early Universe
  | publisher = nasa.gov
  | date = 2008-02-12
  | url = http://www.nasa.gov/centers/jpl/news/Spitzer20080212.html
  | accessdate = 2008-02-25 }}</ref><ref name="nasa2">{{cite web
  | title = Astronomers Uncover One of the Youngest and Brightest Galaxies in the Early Universe
  | publisher = Space Telescope Science Institute Baltimore, Md. / nasa.gov
  | date = 2008-02-12
  | accessdate = 2008-02-25 |url= https://web.archive.org/web/20080217204728/http://www.nasa.gov/mission_pages/hubble/science/young_bright.html }}</ref>

If the redshift, z~7.6,<ref name="esa">{{cite web|title= heic0805: Hubble finds strong contender for galaxy distance record
|publisher= ESA/Hubble
|date= 2008-02-12
|accessdate= 2008-04-04
|url= https://web.archive.org/web/20080308003313/http://www.spacetelescope.org/news/html/heic0805.html }}</ref> is correct, it would explain why the galaxy's faint light reaches us at infrared wavelengths. It could only be observed with Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and the Spitzer Space Telescope's Infrared Array Camera exploiting the natural phenomenon of gravitational lensing: the galaxy cluster Abell 1689, which lies between Earth and A1689-zD1, at a distance of 2.2 billion light-years from us, functions as a natural "magnifying glass" for the light from the far more distant galaxy which lies directly behind it, at 700 million years after the Big Bang, as seen from Earth.<ref name="nasa"/>
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==A1703 zD6==
[[Image:A1703 zD6.jpg|thumb|right|250px|A1703 zD6 is shown. Credit: NASA.]]
A1703 zD6 was reported as being a candidate for being a strongly lensed Lyman-break galaxy, within a 2012 publication by L.D.Bradley and others, within The Astrophysical Journal.<ref>L.D.Bradley et al. - [https://www.researchgate.net/publication/230911859_Through_the_Looking_Glass_Bright_Highly_Magnified_Galaxy_Candidates_at_z__7_behind_A1703 Through the Looking Glass: Bright, Highly Magnified Galaxy Candidates at z ~ 7 behind A1703] The Astrophysical Journal  (Impact Factor: 5.99). 02/2012; 747(1):3. DOI: 10.1088/0004-637X/747/1/3  [Retrieved 2015-11-02]</ref> It has a redshift of 7 (a light travel time of 12.9 billion years), and its J2000 coordinates are 13 15 01.0 +51 50 04. It is located in the Canes Venatici constellation.
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==A2744-JD==

For A2744-JD: Redshift z<sub>p</sub>≅9.8, Light travel distance 13.2 Gly, astronomical object type Galaxy.<ref>{{cite web |url=http://www.nasa.gov/press/2014/october/nasa-s-hubble-finds-extremely-distant-galaxy-through-cosmic-magnifying-glass/#.VJBxQmTF_fY |title=Hubble Finds Distant Galaxy Through Cosmic Magnifying Glass |work=NASA}}</ref><ref>{{cite journal | doi=10.1088/2041-8205/793/1/L12 | volume=793 | issue=1 | title=A GEOMETRICALLY SUPPORTED z ∼ 10 CANDIDATE MULTIPLY IMAGED BY THE HUBBLE FRONTIER FIELDS CLUSTER A2744 | journal=The Astrophysical Journal | pages=L12 |arxiv=1407.3769 |bibcode=2014ApJ...793L..12Z | year=2014 | last1=Zitrin | first1=Adi | last2=Zheng | first2=Wei | last3=Broadhurst | first3=Tom | last4=Moustakas | first4=John | last5=Lam | first5=Daniel | last6=Shu | first6=Xinwen | last7=Huang | first7=Xingxing | last8=Diego | first8=Jose M. | last9=Ford | first9=Holland | last10=Lim | first10=Jeremy | last11=Bauer | first11=Franz E. | last12=Infante | first12=Leopoldo | last13=Kelson | first13=Daniel D. | last14=Molino | first14=Alberto | url=http://hub.hku.hk/bitstream/10722/206809/1/content.pdf }}</ref>

==A2744 YD4==

In 2017, Atacama Large Millimeter Array (ALMA) observed A2744 YD4 and detected a small quantity of dust (the most distant stardust to date) and the first signature of oxygen emitting light only 600 million years after the Big Bang.<ref>{{cite web|title=Ancient Stardust Sheds Light on the First Stars - Most distant object ever observed by ALMA|url=https://www.eso.org/public/news/eso1708/|website=www.eso.org|accessdate=9 March 2017}}</ref>

==Abell 115==

"The very high velocity galaxy (ID 91) is a clear interloper far more than 3000 km s<sup>−1</sup> from other galaxies. The other two high velocity galaxies (IDs 96 and 100), that are close enough in 2D [are] far from the high velocity BCM−A [3C 28] galaxy".<ref name=Barrena>{{ cite journal
|author=R. Barrena, W. Boschin, M. Girardi, and M. Spolaor
|title=The dynamical status of the galaxy cluster Abell 115
|journal=Astronomy & Astrophysics
|date=July 2007
|volume=469
|issue=3
|pages=861–872
|url=https://www.aanda.org/articles/aa/pdf/2007/27/aa7407-07.pdf
|arxiv=
|bibcode=
|doi=10.1051/0004-6361:20077407
|pmid=
|accessdate=1 March 2019 }}</ref>

There are "two structures of cluster-type well recognizable in the plane of the sky and [...] they differ of ~2000 km s<sup>−1</sup> in the [line of sight] LOS velocity. The northern, high velocity subcluster (A115N) is likely centred on the second brightest cluster galaxy (BCM-A, coincident with radio source 3C28) and the northern X-ray peak."<ref name=Barrena/>

==BDF-521==

For BDF-521: Redshift z = 7.008, Light travel distance 13.04 Gly, astronomical object type Galaxy.<ref name="Vanzella et al." />

==BDF-3299==
[[Image:ALMA witnesses assembly of galaxy in early Universe (annotated).jpg|300px|right|thumb|This view is a combination of images from ALMA and the Very Large Telescope. Credit: ESO/R. Maiolino.]]
For BDF-3299: Redshift z = 7.109, Light travel distance 13.05 Gly, Type of astronomical object: Galaxy.<ref name="Vanzella et al.">{{cite journal |last=Vanzella |display-authors=etal |date=2011 |title=Spectroscopic Confirmation of Two Lyman Break Galaxies at Redshift Beyond 7 |journal=The Astrophysical Journal Letters |volume=730 |issue=2 |pages=L35 |doi=10.1088/2041-8205/730/2/L35 |bibcode=2011ApJ...730L..35V |arxiv=1011.5500 }}</ref>
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==EGSY8p7==
[[Image:EGSY8p7 por el Hubble y Spitzer.jpg|right|thumb|300px|EGSY8p7 is imaged by the Hubble Space Telescope and Spitzer Space Telescope space telescopes. Credit: Ivo Labbe - Leiden University, NASA - Hubble & Spitzer Space Telescopes.{{tlx|free media}}]]
EGSY8p7 (EGSY-2008532660) is a distant galaxy in the constellation of Camelopardalis, with a spectroscopic redshift of ''z''&nbsp;=&nbsp;8.68 (photometric redshift 8.57), a light travel distance of 13.2 billion light-years from Earth; therefore, at an age of 13.2 billion years, it is observed as it existed 570 million years after the Big Bang, which occurred 13.8 billion years ago, using the [http://www.keckobservatory.org/recent/entry/new_record_keck_observatory_confirms_most_distant_galaxy W. M. Keck Observatory]. In July 2015, EGSY8p7 was announced as the oldest and most-distant known object, surpassing the previous record holder, EGS-zs8-1, which was determined in May 2015 as the oldest and most distant object. In March 2016, Pascal Oesch, one of the discoverers of EGSY8p7, announced the discovery of GN-z11, an older and more distant galaxy.<ref>{{Cite web | last = Amos | first = Jonathan | title = Hubble sets new cosmic distance record | url = https://www.bbc.com/news/science-environment-35721734 | publisher = BBC News | date = March 3, 2016 | accessdate = March 3, 2016| work = BBC News }}</ref>

A possible explanation for the detection would be that reionization progressed in a "patchy" manner, rather than homogeneously throughout the universe, creating patches where the EGSY8p7 hydrogen Lyman-alpha emissions could travel to Earth, because there were no neutral hydrogen clouds to absorb the emissions.<ref name="Space.com-2015-08-05">{{cite web |url= http://www.space.com/30170-most-distant-galaxy-discovered.html |title= Ancient Galaxy Is Most Distant Ever Found |date= 5 August 2015 |first= Mike |last=Wall |publisher=Space.com }} </ref><ref name="AstronomyNow-2015-08-06">{{cite web |url= http://astronomynow.com/2015/08/06/a-new-record-keck-observatory-measures-most-distant-galaxy/ |title= A new record: Keck Observatory measures most distant galaxy |date= 6 August 2015 |publisher= W. M. Keck Observatory |agency= Astronomy Now }} </ref><ref name="HuffPost-2015-07-15">{{cite web |url= http://www.huffingtonpost.com/mario-de-leo-winkler/the-farthest-object-in-th_b_7795982.html |title= The Farthest Object in the Universe |first= Mario De Leo |last=Winkler |date= 15 July 2015 |publisher= Huffington Post }} </ref><ref name="DailyMail-2015-07-16">{{cite web |url= http://www.dailymail.co.uk/sciencetech/article-3164703/A-galaxy-far-far-away-Astronomers-confirm-star-13-1-billion-light-years-away-distant-known-universe.html |title= A galaxy that rally IS far, far away: Astronomers confirm star system 13.1 billion light-years away is the most distant known in the universe |first1= Jonathan |last1= O'Callaghan |first2= Ellie |last2=Zolfagharifard |date= 17 July 2015 |publisher= Daily Mail |location =London }} </ref><ref name="Caltech-2015-09-03">{{cite web |url= http://www.caltech.edu/news/farthest-galaxy-detected-47761 |title= Farthest Galaxy Detected |date= 3 September 2015 |first= Rod |last=Pyle |publisher= Caltech }} </ref><ref>{{Cite web|title = Farthest Galaxy Detected {{!}} Caltech|url = http://www.caltech.edu/news/farthest-galaxy-detected-47761|accessdate = 2015-09-08}}</ref>
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==EGS-zs8-1==
[[Image:Galaxy-EGS-zs8-1-20150505.jpg|right|thumb|300px|EGS-zs8-1 is viewed by the Hubble Space Telescope. Credit: NASA, ESA, P. Oesch and I. Momcheva (Yale University), and the 3D-HST and HUDF09/XDF Teams.{{tlx|free media}}]]
EGS-zs8-1 is a high-redshift Lyman-break galaxy found at the northern constellation of Boötes.<ref name=paper>{{cite journal |author=Oesch, P.A. |title=A Spectroscopic Redshift Measurement for a Luminous Lyman Break Galaxy at z=7.730 using Keck/MOSFIRE |date=3 May 2015 |journal= The Astrophysical Journal|arxiv=1502.05399 |bibcode = 2015ApJ...804L..30O ''et al.'' |doi=10.1088/2041-8205/804/2/L30 |volume=804 |issue=2 |pages=L30}}</ref> In May 2015, EGS-zs8-1 had the highest spectroscopic redshift of any known galaxy, meaning EGS-zs8-1 was the most distant and the oldest galaxy observed.<ref name="HB-20150505">{{cite web |last1=Villard |first1=Ray |last2=Chou |first2=Felicia |title=Astronomers Set a New Galaxy Distance Record |url=http://hubblesite.org/newscenter/archive/releases/2015/22/full/ |date=5 May 2015 |work=HubbleSite |accessdate=7 May 2015}}</ref><ref name="AP" /> In July 2015, EGS-zs8-1 was surpassed by EGSY8p7 (EGSY-2008532660)<ref name=DailyMail-2015-07-16/>

The redshift of EGS-zs8-1 was measured at z = 7.73, corresponding to a light travel distance of about 13.04 billion light years from Earth, and age of 13.04 billion years. The galaxy shows a high rate of star formation, so it releases its peak radiation at the vacuum ultraviolet part of the electromagnetic spectrum, near the {{convert|121.567|nm|Å|abbr=on}} Lyman-alpha emission line due to the intense radiation from newly formed blue stars, hence it is classified as a Lyman-break galaxy; high-redshift starburst galaxies emitting the Lyman-alpha emission line. Because of the cosmological redshift effect caused by the metric expansion of space, the peak light from the galaxy has become redshifted and has moved into the infrared part of the electromagnetic spectrum.<ref name=paper /> The galaxy has a comoving distance (light travel distance multiplied by the Hubble constant, caused by the metric expansion of space) of about 30 billion light years from Earth.<ref name="NYT">{{cite web |last=Overbye |first=Dennis  |title=Astronomers Measure Distance to Farthest Galaxy Yet |url=https://www.nytimes.com/2015/05/06/science/astronomers-measure-distance-to-farthest-galaxy-yet.html |date=5 May 2015 |work=New York Times |accessdate=6 May 2015 }}</ref>

EGS-zs8-1 was born 670 million years after the Big Bang, during the period of reionization, and it's 15 percent the size of the Milky Way. The galaxy was found to be larger than its other neighbors in that period when the universe was still very young.<ref name="AP">{{cite web |last=Borenstein |first=Seth |title=Astronomers find farthest galaxy: 13.1 billion light-years |url=http://apnews.excite.com/article/20150505/us-sci--farthest_galaxy-46c792535a.html |date=5 May 2015 |publisher=AP News |accessdate=6 May 2015 }}</ref> Its mass at the time the light was emitted is estimated to have been about 15% of the Milky Way's current mass. The galaxy was making new stars at roughly 80 times the rate of the current Milky Way, or equivalent to 800 Solar mass worth of material turning to stars every year.<ref name="NYT" /> The light reaching Earth was made by stars in EGS-zs8-1 that were 100 million to 300 million years old at the time they emitted the light.<ref name="SP-20150505">{{cite web |last=Cofield |first=Calla |title=This Galaxy Far, Far Away Is the Farthest One Yet Found |url=http://www.space.com/29319-farthest-galaxy-ever-found.html |date=5 May 2015 |work=Space.com |accessdate=7 May 2015 }}</ref> The age of EGS-zs8-1 places it in the reionization phase of creation, a time when hydrogen outside the galaxies was switching from a neutral to ionized state. According to the galaxy's discoverers, EGS-zs8-1 and other early galaxies were likely the causes of reionization.<ref name=Phys>{{cite web |author=Staff |title=Astronomers unveil the farthest galaxy |url=http://phys.org/news/2015-05-astronomers-unveil-farthest-galaxy.html |publisher=Phys.org |accessdate=6 May 2015|date=5 May 2015}}</ref><ref>{{Cite web|title = Farthest Galaxy Spotted Yet Is 13 Billion Light-Years Away|url = http://news.nationalgeographic.com/2015/05/150506-most-distant-galaxy-astronomy-space|website = National Geographic News|accessdate = 2015-06-18|first = Michael D.|last = Lemonick|first2 = National Geographic PUBLISHED May|last2 = 06|date = 2015-05-06}}</ref>
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==G2-1408==

For G2-1408: Redshift z = 6.972, Light travel distance 13.03 Gly, and astronomical object type Galaxy.<ref name=sub /><ref>{{Cite journal |arxiv=1010.2754 |last1=Fontana |first1=A. |title=The lack of intense Lyman~alpha in ultradeep spectra of z = 7 candidates in GOODS-S: Imprint of reionization? |journal=The Astrophysical Journal |volume=725 |issue=2 |pages=L205 |last2=Vanzella |first2=E. |last3=Pentericci |first3=L. |last4=Castellano |first4=M. |last5=Giavalisco |first5=M. |last6=Grazian |first6=A. |last7=Boutsia |first7=K. |last8=Cristiani |first8=S. |last9=Dickinson |first9=M. |last10=Giallongo |first10=E. |last11=Maiolino |first11=M. |last12=Moorwood |first12=A. |last13=Santini |first13=P. |year=2010 |doi=10.1088/2041-8205/725/2/L205 |bibcode=2010ApJ...725L.205F}}</ref>

==GN-108036==

GN-108036 is a distant galaxy discovered and confirmed by the Subaru Telescope and the Keck Observatory located in Hawaii; its study was also completed by the Hubble Space Telescope and the Spitzer Space Telescope.<ref>[http://www.nasa.gov/mission_pages/spitzer/news/spitzer20111221.html "NASA Telescopes Help Find Rare Galaxy at Dawn of Time"] NASA. Retrieved 2015-09-22.</ref>

For GN-108036: Redshift z = 7.213, Light travel distance = 13.07 Gly, type of astronomical object =  Galaxy.<ref name=sub>{{cite web |url=http://subarutelescope.org/Pressrelease/2012/06/03/index.html |title=Press Release |publisher=}}</ref><ref>{{cite web |url=http://www.nasa.gov/mission_pages/spitzer/news/spitzer20111221.html |title=NASA – NASA Telescopes Help Find Rare Galaxy at Dawn of Time |publisher=}}</ref>

==GN-z11==
[[Image:Distant galaxy GN-z11 in GOODS-N image by HST.jpg|right|thumb|300px|GN-z11 is superimposed on an image from the GOODS-North survey. Credit: NASA, ESA, P. Oesch (Yale University), G. Brammer (STScI), P. van Dokkum (Yale University), and G. Illingworth (University of California, Santa Cruz).{{tlx|free media}}]]
GN-z11 is a high-redshift galaxy found in the constellation Ursa Major.<ref name="STScI-2016-07-FastFacts">{{cite web |title=Hubble Team Breaks Cosmic Distance Record - Fast Facts |id=STScI-2016-07 |work=HubbleSite |date=March 3, 2016 |accessdate=March 4, 2016 |url=https://web.archive.org/web/20160706052008/http://hubblesite.org/newscenter/archive/releases/2016/07/fastfacts/ }}</ref> GN-z11 is currently the oldest and most distant known galaxy in the observable universe.<ref name="discovery20160303">{{cite web |url=http://news.discovery.com/spacegalaxies/hubble-finds-most-distant-oldest-galaxy-ever-160303.htm |title=Hubble Spies Most Distant, Oldest Galaxy Ever |work=Discovery News |first=Irene |last=Klotz |date=March 3, 2016 |accessdate=March 3, 2016}}</ref> GN-z11 has a spectroscopic redshift of {{nowrap|1=''z'' = 11.09}}, which corresponds to a proper distance of approximately {{convert|32|e9ly|e9pc|abbr=off}}.<ref name="natgeo20160303">{{Cite web |url=http://phenomena.nationalgeographic.com/2016/03/03/astronomers-spot-most-distant-galaxy-yet-at-least-for-now/ |title=Astronomers Spot Most Distant Galaxy—At Least For Now |work=National Geographic |series=No Place Like Home |first=Nadia |last=Drake |date=March 3, 2016 |accessdate=March 4, 2016}}</ref> At first glance, the distance of {{convert|32|e9ly|e9pc|abbr=off}} might seem impossibly far away in a Universe that is only 13.8 billion (short scale) years old, where a light year is the distance light travels in a year, and where nothing can travel faster than the speed of light. However, because of the expansion of the universe, the distance of 2.66 billion light years between GN-z11 and the Milky Way at the time when the light was emitted increased by a factor of (z+1)=12.1 to a distance of 32.2 billion light-years during the 13.4 billion years it has taken the light to reach us.

The object's name is derived from its location in the Great Observatories Origins Deep Survey field of galaxies and its high cosmological redshift number {{nowrap|1=(GN + z11)}}.<ref name="nasa20160303">{{cite web |url=https://www.nasa.gov/feature/goddard/2016/hubble-team-breaks-cosmic-distance-record/ |title=Hubble Team Breaks Cosmic Distance Record |publisher=NASA |date=March 3, 2016 |accessdate=March 10, 2016}}</ref> GN-z11 is observed as it existed 13.4 billion years ago, just 400 million years after the Big Bang;<ref name="Astro draft">{{cite journal |title=A Remarkably Luminous Galaxy at ''z''=11.1 Measured with ''Hubble Space Telescope'' Grism Spectroscopy |journal=The Astrophysical Journal |first1=P. A. |last1=Oesch |first2=G. |last2=Brammer |first3=P. |last3=van Dokkum, ''et al.'' |volume=819 |issue=2 |at=129 |date=March 2016 |arxiv=1603.00461 |bibcode=2016ApJ...819..129O |doi=10.3847/0004-637X/819/2/129}}</ref><ref name="bbc20160303">{{cite web |url=https://www.bbc.com/news/science-environment-35721734 |title=Hubble sets new cosmic distance record |work=BBC News |first=Jonathan |last=Amos |date=March 3, 2016 |accessdate=March 3, 2016}}</ref><ref name="indep20160304">{{cite web |url=https://www.independent.co.uk/news/science/most-distant-object-in-the-universe-spotted-by-hubble-space-telescope-shattering-record-for-the-a6911096.html |title=Most distant object in the universe spotted by Hubble Space Telescope, shattering record for the farthest known galaxy |work=The Independent |first=Andrew |last=Griffin |date=4 March 2016 |accessdate=17 December 2017}}</ref> as a result, GN-z11's distance is sometimes inappropriately<ref name="ucla20130802">{{cite web |url=http://www.astro.ucla.edu/~wright/Dltt_is_Dumb.html |title=Why the Light Travel Time Distance should not be used in Press Releases |publisher=University of California, Los Angeles |first=Edward L. |last=Wright |date=August 2, 2013 |accessdate=March 10, 2016}}</ref> reported as 13.4 billion light years, its light travel distance measurement.<ref name="assocpress20160303">{{cite web |url=http://bigstory.ap.org/article/6c9dcadf6d5f4741b010da09f5841b6f/astronomers-spot-record-distant-galaxy-early-cosmos |title=Astronomers Spot Record Distant Galaxy From Early Cosmos |agency=Associated Press |first=Seth |last=Borenstein |date=March 3, 2016 |accessdate=May 1, 2016 |deadurl=yes |archiveurl=https://web.archive.org/web/20160306044212/http://bigstory.ap.org/article/6c9dcadf6d5f4741b010da09f5841b6f/astronomers-spot-record-distant-galaxy-early-cosmos |archivedate=March 6, 2016 }}</ref><ref name="abcnet20160303">{{cite web |url=http://www.abc.net.au/news/2016-03-04/hubble-space-telescope-observes-most-remote-galaxy-ever-seen/7219846 |title=GN-z11: Astronomers push Hubble Space Telescope to limits to observe most remote galaxy ever seen |publisher=Australian Broadcasting Corporation |date=March 3, 2016 |accessdate=March 10, 2016}}</ref>

The galaxy was identified by a team studying data from the Hubble Space Telescope's Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and Spitzer Space Telescope's Great Observatories Origins Deep Survey-North (GOODS-North).<ref name="heic1604">{{cite web |url=http://www.spacetelescope.org/news/heic1604/ |title=Hubble breaks cosmic distance record |website=SpaceTelescope.org |id=heic1604 |date=March 3, 2016 |access-date=March 3, 2016}}</ref><ref name="Hubble-full">{{cite web |url=http://hubblesite.org/newscenter/archive/releases/2016/07/full/ |title=Hubble Team Breaks Cosmic Distance Record |website=HubbleSite.org |id=STScI-2016-07 |date=March 3, 2016 |accessdate=March 3, 2016}}</ref> The research team used Hubble's Wide Field Camera 3 to measure the distance to GN-z11 spectroscopically, by splitting the light into its component colors to measure the redshift caused by the expansion of the universe.<ref name="yale20160303">{{Cite web |url=http://news.yale.edu/2016/03/03/shattering-cosmic-distance-record-once-again |title=Shattering the cosmic distance record, once again |publisher=Yale University |first=Jim |last=Shelton |date=March 3, 2016 |access-date=March 4, 2016}}</ref> The findings, which were announced in March 2016, revealed the galaxy to be farther away than originally thought, at the distance limit of what the Hubble Telescope can observe. GN-z11 is around 150&nbsp;million years older than the previous record-holder EGSY8p7,<ref name="nasa20160303" /> and is observed (shortly after but) "very close to the end of the so-called Dark Ages of the universe",<ref name="yale20160303" /> and (during but) "near the very beginning" of the reionization era.<ref name="heic1604" />
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==HCM-6A==

HCM-6A is a Lyman-alpha emitter (LAE) galaxy that was found in 2002 by using the W. M. Keck Observatory (Keck II Telescope) in Hawaii.<ref name=Hu/> HCM-6A is located behind the Abell 370 galactic cluster, near Messier 77 (M77).<ref>{{cite journal 
| author=Halton Arp| author2=David Russell| last-author-amp=yes 
| title=A Possible Relationship between Quasars and Clusters of Galaxies
| url=http://www.iop.org/EJ/article/0004-637X/549/2/802/51780.html
| journal=The Astrophysical Journal
| volume=549
| issue=2
| pages=802–819
| doi=10.1086/319438 
| date=2001
| bibcode=2001ApJ...549..802A }}</ref> in the constellation Cetus, which enabled the astronomers to use Abell 370 as a gravitational lens to get a clearer image of the object.<ref name=Hu>{{cite journal 
| author=E. M. Hu 
| title=A Redshift z = 6.56 Galaxy behind the Cluster Abell 370
| url=http://www.iop.org/EJ/article/1538-4357/568/2/L75/16083.html
| journal=The Astrophysical Journal Letters
| volume=568
| issue=2
| pages=L75–L79
| doi=10.1086/340424 
| date=2001
| bibcode=2002ApJ...568L..75H
|arxiv = astro-ph/0203091 
| name-list-format=vanc 
| display-authors=1 
| last2=Cowie 
| first2=L. L. 
| last3=McMahon 
| first3=R. G. 
| last4=Capak 
| first4=P. 
| last5=Iwamuro 
| first5=F. 
| last6=Kneib 
| first6=J.-P. 
| last7=Maihara 
| first7=T. 
| last8=Motohara 
| first8=K. }}</ref><ref>[http://www.subarutelescope.org/Pressrelease/2006/09/13/index.html Press release], National Astronomical Observatory of Japan, September 13, 2006</ref>

For HCM-6A: Redshift z = 6.56 and astronomical object type Galaxy, the first non-quasar galaxy found to exceed redshift 6 and exceeded the redshift of quasar SDSSp J103027.10+052455.0 of z = 6.28<ref name=BBC-2003-03-25 /><ref name=SpaceRef-2003-03-24 /><ref>''New Scientist,'' [https://www.newscientist.com/article/dn2046-new-record-for-universes-most-distant-object.html New record for Universe's most distant object], 17:19 14 March 2002</ref><ref>BBC News, [http://news.bbc.co.uk/2/hi/science/nature/1871043.stm Far away stars light early cosmos], Thursday, 14 March 2002, 11:38 GMT</ref><ref>''The Astrophysical Journal Letters,'' 568:L75–L79, April 1, 2002 ;A Redshift z = 6.56 Galaxy behind the Cluster Abell 370; {{DOI|10.1086/340424}}</ref><ref>{{cite web |url=http://hera.ph1.uni-koeln.de/~heintzma/U/Lens.htm |title=K2.1 HCM 6A&nbsp;— Discovery of a redshift z = 6.56 galaxy lying behind the cluster Abell 370 |publisher=Hera.ph1.uni-koeln.de |date=2008-04-14 |accessdate=2010-10-22 |deadurl=yes |archiveurl=https://web.archive.org/web/20110518140741/http://hera.ph1.uni-koeln.de/~heintzma/U/Lens.htm |archivedate=2011-05-18 |df= }}</ref>

==HVC 127-41-330==

HVC 127-41-330 is a cloud rotating at high speed between Andromeda and the Triangulum Galaxy which may be a dark galaxy because of the speed of its rotation and its predicted mass.<ref name="simon">{{cite journal |author = Josh Simon | title =  Dark Matter in Dwarf Galaxies: Observational Tests of the Cold Dark Matter Paradigm on Small Scales | pages =  4273 | year = 2005  | url = http://www.astro.caltech.edu/~jsimon/thesis/jdsthesis.pdf|archiveurl=https://web.archive.org/web/20060913084945/http://www.astro.caltech.edu/~jsimon/thesis/jdsthesis.pdf|archivedate=2006-09-13| bibcode =  2005PhDT.........2S }}</ref><ref>{{cite web| last =Battersby | first =Stephen | title =Astronomers find first 'dark galaxy' | work =New Scientist | url = https://www.newscientist.com/article.ns?id=dn4272 | date =2003-10-20 |accessdate=December 22, 2012}}</ref>

==IOK-1==
[[Image:IOK-1.jpg|right|thumb|300px|IOK-1 is imaged the Subaru Telescope. Credit: Masanori Iye, Subaru Telscope.{{tlx|free media}}]]
'''Notation:''' '''IOK''' stands for the observers' names Iye, Ota, and Kashikawa.

IOK-1 is a distant galaxy in the constellation Coma Berenice at redshift 6.96.<ref>{{Cite journal |last=Hogan |first=Jenny |year=2006 |title=Journey to the birth of the Universe |journal=Nature |volume=443 |issue=7108 |pages=128–129 |url= |doi=10.1038/443128a |pmid=16971914 |bibcode = 2006Natur.443..128H }}</ref>

The IOK-1's age and composition have been reliably established.<ref>{{Citation |last=Iye |first=Masanori |last2=Ota |first2=Kazuaki |last3=Kashikawa |first3=Nobunari |last4=Furusawa |first4=Hisanori |last5=Hashimoto |first5=Tetsuya |last6=Hattori |first6=Takashi |last7=Matsuda |first7=Yuichi |last8=Morokuma |first8=Tomoki |last9=Ouchi |first9=Masami |year=2006 |title=A galaxy at a redshift z = 6.96 |journal=Nature |volume=443 |issue=7108 |pages=186–188 |id= |doi=10.1038/nature05104 |pmid=16971942 |arxiv=astro-ph/0609393v1 |bibcode=2006Natur.443..186I|display-authors=9 |last10=Shimasaku |first10=Kazuhiro }}</ref><ref>{{Citation |publisher=National Astronomical Observatory of Japan |date=September 13, 2006 |title=Press release |url=http://www.subarutelescope.org/Pressrelease/2006/09/13/index.html }}</ref>
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==LAE J095950.99+021219.1==
[[Image:LAE J095950.99+021219.1.jpg|right|thumb|300px|LAE J095950.99+021219.1 is imaged. Credit: NASA.{{tlx|free media}}]]
LAE J095950.99+021219.1 is about 13 billion light years away and is a Lyman-alpha emitter.<ref name=Rhoads>{{cite journal|last1=Rhoads|first1=James E.|last2=Hibon|first2=Pascale|last3=Malhotra|first3=Sangeeta|last4=Cooper|first4=Michael|last5=Weiner|first5=Benjamin|title=A Lyman Alpha Galaxy at Redshift z=6.944 in the COSMOS Field|journal=The Astrophysical Journal|date=20 June 2012|volume=752|issue=2|pages=L28|doi=10.1088/2041-8205/752/2/L28|arxiv = 1205.3161 |bibcode = 2012ApJ...752L..28R }}</ref>

For LAE J095950.99+021219.1: Redshift z = 6.944, Light travel distance 13.03 Gly, astronomical object type Galaxy.<ref name=Rhoads/>
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==MACS0647-JD==
[[Image:MACS0647-JD.JPG|right|thumb|300px|Hubble Space Telescope is image of MACS0647-JD. Credit: European Space Agency, NASA.{{tlx|free media}}]]
[[Image:Hubble spots candidate for most distant known galaxy.jpg|left|thumb|300px|MACS0647-JD is very young and only a tiny fraction of the size of the Milky Way.<ref>{{cite news|title=Hubble helps find candidate for most distant object in the Universe yet observed|url=http://www.spacetelescope.org/news/heic1217/|accessdate=15 February 2013|newspaper=ESA/Hubble Press Release}}</ref> Credit: NASA, ESA, and M. Postman and D. Coe (Space Telescope Science Institute), and the CLASH team.]]
MACS0647-JD, a galaxy has a redshift of about ''z'' = 9.11, equivalent to a light travel distance of 13.26 billion light-years (4 billion parsecs), formed 130 million years after the Big Bang.<ref>{{cite web |url=http://hubblesite.org/newscenter/archive/releases/2012/36 |work=Space Telescope Science Institute |title=NASA Great Observatories Find Candidate for Most Distant Galaxy Yet Known |date=November 15, 2012 |accessdate=November 17, 2012}}</ref><ref>{{cite journal | bibcode = 2013ApJ...762...32C | title=CLASH: Three Strongly Lensed Images of a Candidate z &ap; 11 Galaxy | journal=The Astrophysical Journal | volume=762 | issue=1 | page=32 | year=2013 | doi=10.1088/0004-637x/762/1/32|arxiv = 1211.3663 | last1=Coe | first1=Dan | last2=Zitrin | first2=Adi | last3=Carrasco | first3=Mauricio | last4=Shu | first4=Xinwen | last5=Zheng | first5=Wei | last6=Postman | first6=Marc | last7=Bradley | first7=Larry | last8=Koekemoer | first8=Anton | last9=Bouwens | first9=Rychard | last10=Broadhurst | first10=Tom | last11=Monna | first11=Anna | last12=Host | first12=Ole | last13=Moustakas | first13=Leonidas A. | last14=Ford | first14=Holland | last15=Moustakas | first15=John | last16=Van Der Wel | first16=Arjen | last17=Donahue | first17=Megan | last18=Rodney | first18=Steven A. | last19=Benítez | first19=Narciso | last20=Jouvel | first20=Stephanie | last21=Seitz | first21=Stella | last22=Kelson | first22=Daniel D. | last23=Rosati | first23=Piero }}</ref><ref name="Coe">{{cite journal |first=Dan |display-authors=etal |last=Coe |title=CLASH: Three Strongly Lensed Images of a Candidate z ~ 11 Galaxy |arxiv=1211.3663|date=November 15, 2012 |doi=10.1088/0004-637X/762/1/32 |volume=762 |issue=1 |journal=The Astrophysical Journal |page=32 |bibcode=2013ApJ...762...32C}}</ref><ref name=heic>{{cite web |url=http://www.spacetelescope.org/images/heic1217b/ |title=Hubble spots three magnified views of most distant known galaxy |work=Hubble Space Telescope |date=November 15, 2012 |accessdate=November 17, 2012}}</ref><ref name="D. Coe">{{cite book |url=http://www.stsci.edu/~dcoe/z11/|author=D. Coe|title=Hubble Spies ...] |publisher=Astrophysical Journal|accessdate=2015-11-02}}</ref>
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==MACS1149-JD1==
[[Image:Hubble and ALMA image of MACS J1149.5+2223.jpg|right|thumb|300px|Hubble and ALMA image shows galaxy cluster MACS J1149.5+2223 with an inset of MACS1149-JD1. Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope, W. Zheng (JHU), M. Postman (STScI), the CLASH Team, Hashimoto et al.{{tlx|free media}}]]
MACS1149-JD1 (also known as PCB2012 3020) is one of the farthest known galaxies from Earth and is at a redshift of about z=9.11,<ref name="Hashimoto2018">{{cite journal |title=The onset of star formation 250 million years after the Big Bang |journal=Nature]] |first=Takuya |last=Hashimoto, ''et al.'' |volume=557 |issue=7705 |pages=392-395 |date=May 2018 |doi=10.1038/s41586-018-0117-z |bibcode=2018Natur.557..392H |arxiv=1805.05966 |pmid=29769675}}</ref> or about {{convert|13.28|e9ly|e9pc|abbr=unit}} light-travel distance.<ref name="alma20180515">{{cite web |url=http://www.almaobservatory.org/en/press-release/alma-finds-most-distant-oxygen-in-the-universe/ |title=ALMA Finds Most-Distant Oxygen in the Universe |publisher=ALMA Observatory |first=Nicolás |last=Lira, ''et al.'' |date=15 May 2018 |accessdate=6 September 2018}}</ref>

For MACS1149-JD1: Redshift z<sub>p</sub>≅9.6, Light travel distance 13.2<ref>{{cite web |url=http://www.nasa.gov/mission_pages/spitzer/news/spitzer20120919.html |title=NASA – NASA Telescopes Spy Ultra-Distant Galaxy |publisher=}}</ref> Gly, astronomical object type Candidate galaxy or protogalaxy.<ref name="zheng2012">{{Cite journal | last1=Zheng | first1=W. | last2=Postman | first2=M. | last3=Zitrin | first3=A. | last4=Moustakas | first4=J. | last5=Shu | first5=X. | last6=Jouvel | first6=S. | last7=Høst | first7=O. | last8=Molino | first8=A. | last9=Bradley | first9=L. | last10=Coe | doi=10.1038/nature11446 | first10=D. | last11=Moustakas | first11=L. A. | last12=Carrasco | first12=M. | last13=Ford | first13=H. | last14=Benítez | first14=N. | last15=Lauer | first15=T. R. | last16=Seitz | first16=S. | last17=Bouwens | first17=R. | authorlink17 = Rychard Bouwens| last18=Koekemoer | first18=A. | last19=Medezinski | first19=E. | last20=Bartelmann | first20=M. | last21=Broadhurst | first21=T. | last22=Donahue | first22=M. |author22-link= Megan Donahue | last23=Grillo | first23=C. | last24=Infante | first24=L. | last25=Jha | first25=S. W. | last26=Kelson | first26=D. D. | last27=Lahav | first27=O. | last28=Lemze | first28=D. | last29=Melchior | first29=P. | last30=Meneghetti | first30=M. | title=A magnified young galaxy from about 500 million years after the Big Bang | journal=Nature | volume=489 | issue=7416 | pages=406–408 | year=2012 | pmid=22996554 | pmc= |arxiv=1204.2305 |bibcode=2012Natur.489..406Z }}</ref>
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==NGC 1275==
[[Image:NGC 1275 Hubble.jpg|right|thumb|300px|Hubble Space Telescope image is of NGC 1275. Credit: HST/NASA/ESA/STScI/AURA.{{tlx|free media}}]]
NGC 1275 consists of two galaxies, a central type-cD galaxy in the Perseus Cluster, and a so-called "high velocity system" (HVS) which lies in front of it. The HVS is moving at 3000&nbsp;km/s<ref>Minkowski R., 1957, in IAU Symp 4, Radio astronomy, p107
</ref> towards the dominant system, and is believed to be merging with the Perseus Cluster. The HVS is not affecting the cD galaxy as it lies at least 200 thousand light years from it.<ref>Gillmon K., Sanders J.S., Fabian A.C., [http://adsabs.harvard.edu/abs/2004MNRAS.348..159G An X-ray absorption analysis of the high-velocity system in NGC 1275], 2004, MNRAS, 348, 159</ref> however tidal interactions are disrupting it and ram-pressure stripping produced by its interaction with the intracluster medium of Perseus is stripping its gas as well as producing large amounts of star formation within it<ref name=Gallagher2010>
{{cite journal
| volume = 42
| pages = 552
| last1 = Gallagher
| first1 = John S., III
| last2 = Lee
| first2 = M.
| last3 = Canning
| first3 = R.
| last4 = Fabian
| first4 = A.
| last5 = O'Connell
| first5 = R. W.
| last6 = Sanders
| first6 = J.
| last7 = Zweibel
| first7 = E.
| title = Dusty Gas and New Stars: Disruption of the High Velocity Intruder Galaxy Falling Towards NGC 1275
| journal = Bulletin of the American Astronomical Society
| date = 2010
|bibcode = 2010AAS...21536308G }}</ref>
{{clear}}

==NGC 1365==

NGC 1365 is notable for its central black hole spinning almost the speed of light.<ref>{{cite journal |url=http://www.nature.com/nature/journal/v494/n7438/full/494432a.html |title=Astrophysics: Black holes in a spin |journal=Nature |first=Christopher S. |last=Reynolds |volume=494 |issue=7438 |pages=432–433 |date=28 February 2013 |doi=10.1038/494432a|bibcode = 2013Natur.494..432R |pmid=23446411}}</ref>

==SDF J132418.3+271455==

For SDF J132418.3+271455: Redshift z = 6.578 and astronomical object type Galaxy.<ref name=SDFz6.6 /><ref name=BBC-2003-03-25>BBC News, [http://news.bbc.co.uk/2/hi/science/nature/2884411.stm Most distant galaxy detected], Tuesday, 25 March 2003, 14:28 GMT</ref><ref name=SpaceRef-2003-03-24>SpaceRef, [http://www.spaceref.com/news/viewpr.html?pid=11046 Subaru Telescope Detects the Most Distant Galaxy Yet and Expects Many More], Monday, March 24, 2003</ref><ref>{{Cite journal |arxiv=astro-ph/0301096 |last1=Kodaira |first1=K. |title=The Discovery of Two Lyman$α$ Emitters Beyond Redshift 6 in the Subaru Deep Field |journal=Publications of the Astronomical Society of Japan |volume=55 |issue=2 |pages=L17 |last2=Taniguchi |first2=Y. |last3=Kashikawa |first3=N. |last4=Kaifu |first4=N. |last5=Ando |first5=H. |last6=Karoji |first6=H. |last7=Ajiki |first7=Masaru |last8=Akiyama |first8=Masayuki |last9=Aoki |first9=Kentaro |last10=Doi |first10=Mamoru |last11=Fujita |first11=Shinobu S. |last12=Furusawa |first12=Hisanori |last13=Hayashino |first13=Tomoki |last14=Imanishi |first14=Masatoshi |last15=Iwamuro |first15=Fumihide |last16=Iye |first16=Masanori |last17=Kawabata |first17=Koji S. |last18=Kobayashi |first18=Naoto |last19=Kodama |first19=Tadayuki |last20=Komiyama |first20=Yutaka |last21=Kosugi |first21=George |last22=Matsuda |first22=Yuichi |last23=Miyazaki |first23=Satoshi |last24=Mizumoto |first24=Yoshihiko |last25=Motohara |first25=Kentaro |last26=Murayama |first26=Takashi |last27=Nagao |first27=Tohru |last28=Nariai |first28=Kyoji |last29=Ohta |first29=Kouji |last30=Ohyama |first30=Youichi |year=2003 |doi=10.1093/pasj/55.2.L17 |display-authors=29|bibcode = 2003PASJ...55L..17K }}</ref>

==SDF J132522.3+273520==

For SDF J132522.3+273520: Redshift z = 6.597, astronomical object type Galaxy.<ref name="z.gt.5">{{cite journal |last1=Taniguchi |first1=Yoshi |title=Star Forming Galaxies at z > 5 |journal=Proceedings of the International Astronomical Union |date=23 June 2008 |volume=3 |issue=S250 |pages=429 |arxiv=0804.0644 |doi=10.1017/S1743921308020796|bibcode=2008IAUS..250..429T }}</ref><ref name=SDFz6.6>{{cite journal |url=http://pasj.asj.or.jp/v57/n1/570114/57012649.pdf |bibcode=2005PASJ...57..165T |doi=10.1093/pasj/57.1.165 |title=The SUBARU Deep Field Project: Lymanα Emitters at a Redshift of 6.6 |journal=Publications of the Astronomical Society of Japan |volume=57 |pages=165–182 |year=2005 |last1=Taniguchi |first1=Yoshiaki |last2=Ajiki |first2=Masaru |last3=Nagao |first3=Tohru |last4=Shioya |first4=Yasuhiro |last5=Murayama |first5=Takashi |last6=Kashikawa |first6=Nobunari |last7=Kodaira |first7=Keiichi |last8=Kaifu |first8=Norio |last9=Ando |first9=Hiroyasu |last10=Karoji |first10=Hiroshi |last11=Akiyama |first11=Masayuki |last12=Aoki |first12=Kentaro |last13=Doi |first13=Mamoru |last14=Fujita |first14=Shinobu S. |last15=Furusawa |first15=Hisanori |last16=Hayashino |first16=Tomoki |last17=Iwamuro |first17=Fumihide |last18=Iye |first18=Masanori |last19=Kobayashi |first19=Naoto |last20=Kodama |first20=Tadayuki |last21=Komiyama |first21=Yutaka |last22=Matsuda |first22=Yuichi |last23=Miyazaki |first23=Satoshi |last24=Mizumoto |first24=Yoshihiko |last25=Morokuma |first25=Tomoki |last26=Motohara |first26=Kentaro |last27=Nariai |first27=Kyoji |last28=Ohta |first28=Koji |last29=Ohyama |first29=Youichi |last30=Okamura |first30=Sadanori |display-authors=29|arxiv = astro-ph/0407542 }}</ref>

==SPT0615-JD==

For SPT0615-JD: Redshift z = 9.9, Light travel distance 13.27 Gly, astronomical object type Galaxy.<ref>
{{cite journal |arxiv=1801.03103 |title= A Candidate z∼10 Galaxy Strongly Lensed into a Spatially Resolved Arc|journal= The Astrophysical Journal|volume= 864|pages= L22|last1= Salmon|first1= Brett|last2= Coe|first2= Dan|last3= Bradley|first3= Larry|last4= Bradač|first4= Marusa|last5= Huang|first5= Kuang-Han|last6= Strait|first6= Victoria|last7= Oesch|first7= Pascal|last8= Paterno-Mahler|first8= Rachel|last9= Zitrin|first9= Adi|last10= Acebron|first10= Ana|last11= Cibirka|first11= Nathália|last12= Kikuchihara|first12= Shotaro|last13= Oguri|first13= Masamune|last14= Brammer|first14= Gabriel B|last15= Sharon|first15= Keren|last16= Trenti|first16= Michele|last17= Avila|first17= Roberto J|last18= Ogaz|first18= Sara|last19= Andrade-Santos|first19= Felipe|last20= Carrasco|first20= Daniela|last21= Cerny|first21= Catherine|last22= Dawson|first22= William|last23= Frye|first23= Brenda L|last24= Hoag|first24= Austin|last25= Jones|first25= Christine|last26= Mainali|first26= Ramesh|last27= Ouchi|first27= Masami|last28= Rodney|first28= Steven A|last29= Stark|first29= Daniel|last30= Umetsu|first30= Keiichi|year= 2018|doi= 10.3847/2041-8213/aadc10}}</ref>

==SXDF-NB1006-2==

SXDF-NB1006-2 is a distant galaxy located in the Cetus constellation, with a spectroscopic redshift of ''z'' = 7.213 or 12.91 billion light-years away.<ref name=TMT-SXDF-NB1006-2>Thirty Meter Telescope, [http://www.tmt.org/gallery/miscellaneous/sxdf-nb1006-2 TMT - SXDF-NB1006-2] |url=https://web.archive.org/web/20130524151017/http://www.tmt.org/gallery/miscellaneous/sxdf-nb1006-2 |date=2013-05-24 , NAOJ (accessed 16 November 2012)</ref> It was discovered by the Subaru XMM-Newton Deep Survey Field.<ref name=TMT-SXDF-NB1006-2/> The galaxy was claimed to be the most distant galaxy at announcement in June 2012, as the more distant claimants were not confirmed spectroscopically at the time. It exceeded the previous confirmed distance holder, GN-108036, also discovered by the Subaru.<ref>SPACE.com, [http://www.space.com/16135-distant-galaxy.html "Newfound Galaxy May Be Most Distant Ever Seen"], 14 June 2012 (accessed 18 December 2012)</ref> It contains the oldest oxygen in the Universe.<ref>{{Cite journal|doi=10.1126/science.aag0615|url=http://www.sciencemag.org/news/2016/06/ancient-galaxy-holds-oldest-oxygen-universe?et_rid=33785738&et_cid=567570|title=Ancient galaxy holds oldest oxygen in universe / Science / AAAS|journal=Science|date=2016-06-16|last1=Perkins|first1=Sid}}</ref>

==UDFy-33436598==

For UDFy-33436598: Redshift z<sub>p</sub>≅8.6, Light travel distance 13.1 Gly, astronomical object type Candidate galaxy or protogalaxy.<ref name=eso>{{cite web |url=http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50876 |title=ESA Science & Technology: The Hubble eXtreme Deep Field (annotated) |publisher=}}</ref>

==UDFy-38135539==

For UDFy-38135539: Redshift z = 8.55, Light travel distance 13.1 Gly, astronomical object type Candidate galaxy or protogalaxy.
A spectroscopic redshift of z = 8.55 was claimed for this source in 2010,<ref name=UDFy-38135539>{{cite web |url=https://www.newscientist.com/article/dn19603-dim-galaxy-is-most-distant-object-yet-found.html |title=Dim galaxy is most distant object yet found |author=David Shiga |work=New Scientist}}</ref> but has subsequently been shown to be mistaken.<ref name="Bunker2013">{{Cite journal |bibcode=2013MNRAS.430.3314B |title=VLT/XSHOOTER and Subaru/MOIRCS spectroscopy of HUDF.YD3: no evidence for Lyman & |journal=Monthly Notices of the Royal Astronomical Society |volume=430 |issue=4 |pages=3314 |publisher= |author1=Bunker |first1=Andrew J. |last2=Caruana |first2=Joseph |last3=Wilkins |first3=Stephen M. |last4=Stanway |first4=Elizabeth R. |last5=Lorenzoni |first5=Silvio |last6=Lacy |first6=Mark |last7=Jarvis |first7=Matt J. |last8=Hickey |first8=Samantha |year=2013 |doi=10.1093/mnras/stt132|arxiv = 1301.4477 }}</ref>

==ULAS J1120+0641==
[[Image:ULAS J1120+0641.jpg|right|thumb|300px|In this 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. Credit: ESO/UKIDSS/SDSS.{{tlx|free media}}]]
ULAS J1120+0641 is the second most distant known quasar as of 6 December 2017, after ULAS J1342+0928.<ref name="NAT-20171206"/><ref name="NASA-20171206"/><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 |accessdate=6 December 2017 }}</ref> ULAS J1120+0641 (at a comoving distance of 28.85 billion light-years) was the first quasar discovered beyond a redshift of 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, ''et al'' |journal= Spitzer Proposals |volume=80114 |pages= 80114 |date=May 2011 |bibcode=2011sptz.prop80114W }}</ref> Its discovery was reported in June 2011.<ref name=Mortlock-2011-05/> 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 web|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/|accessdate=30 June 2011|newspaper=The Atlantic|date=30 June 2011}}</ref>

"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."<ref name=atlantic/>

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 }}</ref>

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 |accessdate=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, close (on the plane of the sky) to σ Leo. The quasar was discovered by a telescope that operates at infrared wavelengths, 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 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 web|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|accessdate=30 June 2011|date=2011-06-30}}</ref>

UKIDSS is a near infrared photometric survey, so the original discovery was only a photometric redshift of z<sub>phot</sub>&gt;6.5.<ref name = Mortlock-2011-05/> 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-2011-05/>

ULAS J1120+0641 has a measured redshift of 7.085, which corresponds to a comoving distance of 28.85 billion light-years from Earth. Although this may appear to be larger than the size of the observable universe, this is not in fact a contradiction. As of 2011, it is the most distant quasar yet observed.<ref name=bbcnews/> 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 web |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 |accessdate= 2011-07-01}}</ref> This is 100 million years earlier than light from the most distant previously known quasar.<ref name=wapo>{{cite web|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|accessdate=30 June 2011|newspaper=Washington Post|date=30 June 2011}}</ref>

The quasar's luminosity is estimated at {{val|6.3|e=13}} solar luminosities. This energy output is generated by a supermassive black hole estimated at {{val|2|+1.5|-0.7|e=9}} solar masses.<ref name=Mortlock-2011-05/><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 |accessdate=2011-06-30 }}</ref> While the black hole powers the quasar, the light does not come from the black hole itself.<ref name=Mortlock-2011-05/>

"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/><ref name=Mortlock-2011-05/>

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 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 web|last=Amos|first=Jonathan|title='Monster' driving cosmic beacon|url=https://www.bbc.co.uk/news/science-environment-13964767|accessdate=30 June 2011|newspaper=BBC News|date=30 June 2011}}</ref> The spectrum also lacked any significant indication of non-Big Bang nucleosynthesis metals, where 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 stars 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 web |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 |accessdate= March 15, 2013 |author= Matthew Francis }}</ref>

The supermassive black hole in ULAS J1120+0641 has a higher mass than was expected, as 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 }}[https://arxiv.org/abs/1106.6090 preprint of this paper]</ref>
{{clear}}

==ULAS J1342+0928==

ULAS J1342+0928 is the most distant known quasar detected and contains the most distant and oldest known supermassive black hole.<ref name="NAT-20171206"/><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 |accessdate=6 December 2017 }}</ref>

"This black hole grew far larger than we expected in only 690 million years after the Big Bang, which challenges our theories about how black holes form."<ref name="NASA-20171206"/><ref name="SPTZR-2017">{{cite web |author=Decarli, Roberto, ''et al.'' |title=Rest-frame optical photometry of a z-7.54 quasar and its environment |url=http://ssc.spitzer.caltech.edu/warmmission/scheduling/approvedprograms/ddt/13201.txt |date=September 2017 |work=CalTech |accessdate=6 December 2017 }}</ref> at a reported redshift of z = 7.54, surpassing the redshift of 7 for the previously known most distant quasar ULAS J1120+0641.<ref name="NAT-20171206" /> The ULAS J1342+0928 quasar is located in the Boötes constellation.<ref name="DJM-2008">{{cite web |author=Staff |title=Finding the constellation which contains given sky coordinates |url=http://djm.cc/constellation.html |work=djm.com |accessdate=6 December 2017 }}</ref> The related supermassive black hole is reported to be "800 million times the mass of the sun".<ref name="SPC-20171206" />

On 6 December 2017,<ref name="NAT-20171206" /> astronomers published that they had found the quasar using data from the Wide-field Infrared Survey Explorer (WISE)<ref name="NASA-20171206" /> combined with ground-based surveys from one of the Magellan Telescopes at Las Campanas Observatory in Chile, as well as the Large Binocular Telescope in Arizona and the Gemini Observatory (Gemini North telescope) in Hawaii. The related black hole of the quasar existed when the universe was about 690 million years old (about 5 percent of its currently known age of 13.80 billion years).<ref name="NAT-20171206" />

The quasar comes from a time known as "the epoch of reionization", when the universe emerged from its Dark Ages.<ref name="SPC-20171206" /> Extensive amounts of dust and gas have been detected to be released from the quasar into the interstellar medium of its host galaxy.<ref name="APJL-20171206">{{cite journal |author=Venemans, Bram P., ''et al.'' |title=Copious Amounts of Dust and Gas in a z = 7.5 Quasar Host Galaxy |url=http://iopscience.iop.org/article/10.3847/2041-8213/aa943a |date=6 December 2017 |journal=The Astrophysical Journal Letters |volume=851 |number=1 |accessdate=6 December 2017 }}</ref>

ULAS J1342+0928 has a measured redshift of 7.54, which corresponds to a comoving distance of 29.36 billion light-years from Earth.<ref name="NAT-20171206" /><ref name="CosmoCalc-2017">{{cite web | last=Wright |first=Ned |title=Ned Wright's Javascript Cosmology Calculator |url=http://www.astro.ucla.edu/~wright/CosmoCalc.html |date=24 April 2016 |work=UCLA | accessdate=7 December 2017}}</ref> As of 2017, it is the most distant quasar yet observed. The quasar emitted the light observed on Earth today less than 690 million years after the Big Bang, about 13.1 billion years ago.<ref name="SPC-20171206" /><ref name="VRG-20171206">{{cite web|url=https://www.theverge.com/2017/12/6/16738652/quasar-supermassive-black-hole-early-universe-big-bang|title=The most distant supermassive black hole ever found holds secrets to the early Universe - We’re seeing how it looked when the Universe was a toddler|last=Grush|first=Loren|date=6 December 2017|work=TheVerge|accessdate=6 December 2017}}</ref>

The quasar's luminosity is estimated at {{val|4|e=13}} solar luminosities.<ref name="NAT-20171206" /> This energy output is generated by a supermassive black hole estimated at {{val|8|e=8}} solar masses.<ref name="NAT-20171206" /> "This particular quasar is so bright that it will become a gold mine for follow-up studies and will be a crucial laboratory to study the early universe."<ref name="EB-2017">{{cite web |last=Bañados |first=Eduardo |title=Eduardo Bañados - Bio/CV |url=https://users.obs.carnegiescience.edu/~ebanados/index.html |date=2017 |work=Carnegie Institution for Science |accessdate=7 December 2017 }}</ref><ref name="SPC-20171206" />

The light from ULAS J1342+0928 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 cosmic Dark Ages, so observing a quasar from before the transition is of major interest to theoreticians.<ref name="SA-20110629">{{cite web |author=Matson, John |title=Brilliant, but Distant: Most Far-Flung Known Quasar Offers Glimpse into Early Universe |url=http://www.scientificamerican.com/article.cfm?id=farthest-quasar |date=29 June 2011 |work=Scientific American  |accessdate=7 December 2017}}</ref><ref name="CW-2011">{{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 }}[https://arxiv.org/abs/1106.6090 preprint of this paper]</ref> Because of their high ultraviolet luminosity, quasars also are some of the best sources for studying the reionization process. The discovery is also described as challenging theories of black hole formation, by having a supermassive black hole much larger than expected at such an early stage in the Universe's history,<ref name="NASA-20171206"/> though this is not the first distant quasar to offer such a challenge.<ref name=Nature2015-02-25a/>

"A black hole that grew to gargantuan size in the Universe's first billion years is by far the largest yet spotted from such an early date, researchers have announced. The object, discovered by astronomers in 2013, is 12 billion times as massive as the Sun, and six times greater than its largest-known contemporaries. Its existence poses a challenge for theories of the evolution of black holes, stars and galaxies, astronomers say. Light from the black hole took 12.9 billion years to reach Earth, so astronomers see the object as it was 900 million years after the Big Bang."<ref name=Nature2015-02-25a/> "That "is actually a very short time" for a black hole to have grown so large."<ref name=Nature2015-02-25a>{{cite web|url=https://www.nature.com/news/young-black-hole-had-monstrous-growth-spurt-1.16989|title=Young black hole had monstrous growth spurt|author=Davide Castelvecchi and Xue-Bing Wu|date=25 February 2015|accessdate=9 December 2017|publisher=Nature }}</ref>

"Now, researchers from the Max Planck Institute for Astronomy (MPIA) have discovered three quasars that challenge conventional wisdom on black hole growth. These quasars are extremely massive, but should not have had sufficient time to collect all that mass. The astronomers observed quasars whose light took nearly 13 billion years to reach Earth. In consequence, the observations show these quasars not as they are today, but as they were almost 13 billion years ago, less than a billion years after the big bang. The quasars in question have about a billion times the mass of the sun. All current theories of black hole growth postulate that, in order to grow that massive, the black holes would have needed to collect infalling matter, and shine brightly as quasars, for at least a hundred million years. But these three quasars proved to be have been active for a much shorter time, less than 100,000 years."<ref name=Phys_org2017-05-11a/>

"This is a surprising result. We don't understand how these young quasars could have grown the supermassive black holes that power them in such a short time."<ref name=Phys_org2017-05-11a>{{cite web|url=https://phys.org/news/2017-05-discovery-early-universe-poses-black.html|title=Discovery in the early universe poses black hole growth puzzle|author=Christina Eilers|date=11 May 2015|accessdate=9 December 2017|publisher=Phys.org }}</ref>

A small minority of sources argue that distant supermassive black holes whose large size is hard to explain so soon after the Big Bang, such as ULAS J1342+0928,<ref name="NASA-20171206"/> may be evidence that our universe is the result of a Big Bounce, instead of a Big Bang, with these supermassive black holes being formed before the Big Bounce.<ref name=News_com-AU_2017-12-07a>{{cite web|url=http://www.news.com.au/technology/science/space/black-hole-at-the-dawn-of-time-challenges-our-understanding-of-how-the-universe-was-formed/news-story/3279356705a47d45416ae2e6ead41175|title=Black hole at the dawn of time challenges our understanding of how the universe was formed|author=Jamie Seidel|date=7 December 2017|accessdate=9 December 2017|publisher=News Corp Australia  }}</ref>

"It had reached its size just 690 million years after the point beyond which there is nothing. The most dominant scientific theory of recent years describes that point as the Big Bang — a spontaneous eruption of reality as we know it out of a quantum singularity. But another idea has recently been gaining weight: that the universe goes through periodic expansions and contractions — resulting in a “Big Bounce”. And the existence of early black holes has been predicted to be a key telltale as to whether or not the idea may be valid. This one is very big. To get to its size — 800 million times more mass than our Sun — it must have swallowed a lot of stuff. ... As far as we understand it, the universe simply wasn’t old enough at that time to generate such a monster."<ref name=News_com-AU_2017-12-07a/>

"This new theory that accepts that the Universe is going through periodic expansions and contractions is called "Big Bounce""<ref name=YouMagazine2017-12-08a>{{cite web|url=http://www.youmagazine.gr/2017/12/23256-mia-mavri-trypa-arhaioteri-apo-to-sympan-video/|title=A Black Hole that is more ancient than the Universe|author=Youmagazine staff|date=8 December 2017|accessdate=9 December 2017|publisher=You Magazine (Greece)|language=Greek }}</ref>

==z7 GSD 3811==

For z7 GSD 3811: z = 7.66, light travel distance = 13.11 Gly, and it is a galaxy<ref>{{Cite journal| first1=M. |last1=Song |first2=S. L. |last2=Finkelstein |first3=R. C. |last3=Livermore |first4=P. L. |last4=Capak |first5=M. |last5=Dickinson |first6=A. |last6=Fontana
| title=Keck/MOSFIRE Spectroscopy of z = 7–8 Galaxies: Lyman-alpha Emission from a Galaxy at z = 7.66 |journal=The Astrophysical Journal |volume=826 |issue=2 |pages=113 |arxiv=1602.02160 | year=2016 |doi=10.3847/0004-637X/826/2/113 |bibcode=2016ApJ...826..113S }}</ref>

==z8 GND 5296==

z8_GND_5296 is a dwarf galaxy<ref name="wapost20131023">{{cite web |url=https://www.washingtonpost.com/national/health-science/newly-detected-galaxy-is-the-most-distant-ever/2013/10/23/415ac854-3a78-11e3-b7ba-503fb5822c3e_story.html |title=Newly identified galaxy is the most distant ever confirmed |work=The Washington Post |first=Meeri |last=Kim |date=23 October 2013 |accessdate=22 October 2014}}</ref> discovered in October 2013 which has the highest redshift that has been confirmed through the Lyman-alpha emission line of hydrogen,<ref name="Finkelstein2013">{{cite journal |title=A galaxy rapidly forming stars 700 million years after the Big Bang at redshift 7.51 |journal=Nature |first1=S. L. |last1=Finkelstein |first2=C. |last2=Papovich |first3=M. |last3=Dickinson |first4=M. |last4=Song |first5=V. |last5=Tilvi |first6=A. M. |last6=Koekemoer |first7=K. D. |last7=Finkelstein |first8=B. |last8=Mobasher |first9=H. C. |last9=Ferguson |first10=M. |last10=Giavalisco |first11=N. |last11=Reddy |first12=M. L. N. |last12=Ashby |first13=A. |last13=Dekel |first14=G. G. |last14=Fazio |first15=A. |last15=Fontana |first16=N. A. |last16=Grogin |first17=J.-S. |last17=Huang |first18=D. |last18=Kocevski |first19=M. |last19=Rafelski |first20=B. J. |last20=Weiner |first21=S. P. |last21=Willner |display-authors=5 |volume=502 |issue=7472 |pages=524–527 |year=2013 |arxiv=1310.6031 |doi=10.1038/nature12657|bibcode = 2013Natur.502..524F |pmid=24153304}}</ref><ref name="simbad">{{cite web |title=NAME FIGS GN1 1292|url=http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=FIGS+GN1+1292&submit=SIMBAD+search |accessdate=6 October 2016}}</ref> placing it among the oldest and most distant known galaxies at approximately {{convert|13.1|e9ly|Gpc|}} from Earth.<ref name="readhorn20131026">{{cite web |url=http://www.readthehorn.com/news/research/85364/farthest_galaxy_ever_seen_discovered_by_ut_researchers |title=Farthest galaxy ever seen discovered by UT researchers |work=The Horn |first=Mihir |last=Shukla |date=26 October 2013 |accessdate=30 October 2013}}</ref><ref name="unitoday20131023">{{cite web |url=http://www.universetoday.com/105694/taking-measure-a-new-most-distant-galaxy/ |title=Taking Measure: A 'New' Most Distant Galaxy |work=Universe Today |first=Matthew |last=Francis |date=23 October 2013 |accessdate=30 October 2013}}</ref> It is "seen as it was at a time just 700 million years after the Big Bang [...] when the universe was only about 5 percent of its current age of 13.8 billion years".<ref name="utexas20131023">{{cite web |url=http://www.utexas.edu/news/2013/10/23/texas-astronomer-discovers-most-distant-known-galaxy/ |title=Texas Astronomer Discovers Most Distant Known Galaxy |publisher=University of Texas at Austin |first=Rebecca |last=Johnson |date=23 October 2013}}</ref> The galaxy is at a redshift of 7.51, and it is a neighbour to what was announced then as the second-most distant galaxy with a redshift of 7.2. The galaxy in its observable timeframe was producing stars at a phenomenal rate, equivalent in mass to about 330 Sun's per year.<ref name="Finkelstein2013" />

==Acknowledgements==

The content on this page was first contributed by: Henry A. Hoff.

Initial content for this page in some instances came from [http://www.wikiversity.org Wikiversity].

==See also==
{{div col|colwidth=12em}}
* [[Galaxy radiation astronomy]]
{{Div col end}}

==References==
{{reflist|2}}

==External links==
* [http://simbad.u-strasbg.fr/simbad/ Simbad at Strasburg]

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