View source for Astronomy:Direct collapse black hole

{{Short description|High-mass black hole seeds}}
[[File:Artist’s impression of supermassive black hole seed.jpg|thumb|Artist's impression for the formation of a massive black hole seed via the direct black hole channel.<ref name=":2">{{Cite web|publisher=Chandra X-ray Observatory |website=Press Room |title=NASA Telescopes Find Clues For How Giant Black Holes Formed So Quickly |date=24 May 2016|url=https://chandra.si.edu/press/16_releases/press_052416.html|access-date=2020-08-27}}</ref>]]
'''Direct collapse black holes''' ('''DCBHs''') are high-mass [[Astronomy:Black hole|black hole]] seeds,<ref>{{Cite journal|last1=Loeb|first1=Abraham|last2=Rasio|first2=Frederic A.|date=1994-09-01|title=Collapse of primordial gas clouds and the formation of quasar black holes|url=http://adsabs.harvard.edu/abs/1994ApJ...432...52L|journal=The Astrophysical Journal|volume=432|pages=52–61|doi=10.1086/174548|arxiv=astro-ph/9401026|bibcode=1994ApJ...432...52L|s2cid=17042784}}</ref><ref name=":0">{{Cite journal|last1=Bromm|first1=Volker|last2=Loeb|first2=Abraham|date=2003-10-01|title=Formation of the First Supermassive Black Holes|url=http://adsabs.harvard.edu/abs/2003ApJ...596...34B|journal=The Astrophysical Journal|volume=596|issue=1|pages=34–46|doi=10.1086/377529|arxiv=astro-ph/0212400|bibcode=2003ApJ...596...34B|s2cid=14419385}}</ref><ref name=":4">{{Cite journal|last1=Lodato|first1=Giuseppe|last2=Natarajan|first2=Priyamvada|date=2006-10-01|title=Supermassive black hole formation during the assembly of pre-galactic discs|url=http://adsabs.harvard.edu/abs/2006MNRAS.371.1813L|journal=Monthly Notices of the Royal Astronomical Society|volume=371|issue=4|pages=1813–1823|doi=10.1111/j.1365-2966.2006.10801.x|arxiv=astro-ph/0606159|bibcode=2006MNRAS.371.1813L|s2cid=13448595}}</ref><ref>{{Cite web|last=Siegel|first=Ethan|title='Direct Collapse' Black Holes May Explain Our Universe's Mysterious Quasars|url=https://www.forbes.com/sites/startswithabang/2017/12/26/direct-collapse-black-holes-may-explain-our-universes-mysterious-quasars/|access-date=2020-08-27|website=Forbes|language=en}}</ref> putatively formed within the [[Astronomy:Redshift|redshift]] range ''z''=15–30,<ref>{{Cite journal|last1=Yue|first1=Bin|last2=Ferrara|first2=Andrea|last3=Salvaterra|first3=Ruben|last4=Xu|first4=Yidong|last5=Chen|first5=Xuelei|date=2014-05-01|title=The brief era of direct collapse black hole formation|url=http://adsabs.harvard.edu/abs/2014MNRAS.440.1263Y|journal=Monthly Notices of the Royal Astronomical Society|volume=440|issue=2|pages=1263–1273|doi=10.1093/mnras/stu351|arxiv=1402.5675|bibcode=2014MNRAS.440.1263Y|s2cid=119275449}}</ref> when the [[Astronomy:Universe|Universe]] was about 100–250 million years old. Unlike seeds formed from the first population of [[Astronomy:Star|star]]s (also known as Population III stars), direct collapse black hole seeds are formed by a direct, [[Physics:General relativity|general relativistic]] instability. They are very massive, with a typical mass at formation of ~{{val|e=5|u={{Solar mass|lk=y}}}}.<ref name=":0" /><ref>{{Cite journal|last1=Rees|first1=Martin J.|last2=Volonteri|first2=Marta|date=2007-04-01|title=Massive black holes: formation and evolution|journal=Black Holes from Stars to Galaxies – Across the Range of Masses|url=http://adsabs.harvard.edu/abs/2007IAUS..238...51R|volume=238|pages=51–58|doi=10.1017/S1743921307004681|arxiv=astro-ph/0701512|bibcode=2007IAUS..238...51R|s2cid=14844338}}</ref> This category of black hole seeds was originally proposed theoretically to alleviate the challenge in building [[Astronomy:Supermassive black hole|supermassive black hole]]s already at redshift z~7, as numerous observations to date have confirmed.<ref name=":2" /><ref>{{Cite journal|last1=Bañados|first1=Eduardo|last2=Venemans|first2=Bram P.|last3=Mazzucchelli|first3=Chiara|last4=Farina|first4=Emanuele P.|last5=Walter|first5=Fabian|last6=Wang|first6=Feige|last7=Decarli|first7=Roberto|last8=Stern|first8=Daniel|last9=Fan|first9=Xiaohui|last10=Davies|first10=Frederick B.|last11=Hennawi|first11=Joseph F.|date=2018-01-01|title=An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5|url=http://adsabs.harvard.edu/abs/2018Natur.553..473B|journal=Nature|volume=553|issue=7689|pages=473–476|doi=10.1038/nature25180|pmid=29211709|arxiv=1712.01860|bibcode=2018Natur.553..473B|s2cid=205263326}}</ref><ref>{{Cite journal|last1=Fan|first1=Xiaohui|last2=Narayanan|first2=Vijay K.|last3=Lupton|first3=Robert H.|last4=Strauss|first4=Michael A.|last5=Knapp|first5=Gillian R.|last6=Becker|first6=Robert H.|last7=White|first7=Richard L.|last8=Pentericci|first8=Laura|last9=Leggett|first9=S. K.|last10=Haiman|first10=Zoltán|last11=Gunn|first11=James E.|date=2001-12-01|title=A Survey of z>5.8 Quasars in the Sloan Digital Sky Survey. I. Discovery of Three New Quasars and the Spatial Density of Luminous Quasars at z~6|url=http://adsabs.harvard.edu/abs/2001AJ....122.2833F|journal=The Astronomical Journal|volume=122|issue=6|pages=2833–2849|doi=10.1086/324111|arxiv=astro-ph/0108063|bibcode=2001AJ....122.2833F|s2cid=119339804}}</ref><ref>{{Cite journal|last1=Yang|first1=Jinyi|last2=Wang|first2=Feige|last3=Fan|first3=Xiaohui|last4=Hennawi|first4=Joseph F.|last5=Davies|first5=Frederick B.|last6=Yue|first6=Minghao|last7=Banados|first7=Eduardo|last8=Wu|first8=Xue-Bing|last9=Venemans|first9=Bram|last10=Barth|first10=Aaron J.|last11=Bian|first11=Fuyan|date=2020-07-01|title=Poniua'ena: A Luminous z = 7.5 Quasar Hosting a 1.5 Billion Solar Mass Black Hole|journal=The Astrophysical Journal Letters|volume=897|issue=1|pages=L14|doi=10.3847/2041-8213/ab9c26|arxiv=2006.13452|bibcode=2020ApJ...897L..14Y|s2cid=220042206 |doi-access=free }}</ref><ref>{{Cite web|date=2020-06-24|title=Monster Black Hole Found in the Early Universe|url=https://www.gemini.edu/pr/monster-black-hole-found-early-universe|access-date=2020-09-06|website=Gemini Observatory|language=en}}</ref>

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== Formation ==
Direct collapse black holes (DCBHs) are massive black hole seeds theorized to have formed in the high-redshift Universe and with typical masses at formation of ~{{val|e=5|u={{Solar mass|lk=y}}}}, but spanning between {{val|e=4|u={{Solar mass}}}} and {{val|e=6|u={{Solar mass}}}}. The environmental physical conditions to form a DCBH (as opposed to a cluster of [[Astronomy:Star|star]]s) are the following:<ref name=":0" /><ref name=":4" />

# [[Astronomy:Metallicity|Metal-free]] gas (gas containing only [[Chemistry:Hydrogen|hydrogen]] and [[Chemistry:Helium|helium]]).
# Atomic-cooling gas.
# Sufficiently large flux of [[Physics:Lyman–Werner photons|Lyman–Werner photons]], in order to destroy hydrogen molecules, which are very efficient gas coolants.<ref>{{Cite journal|last1=Regan|first1=John A.|last2=Johansson|first2=Peter H.|last3=Wise|first3=John H.|date=2014-11-01|title=The Direct Collapse of a Massive Black Hole Seed under the Influence of an Anisotropic Lyman–Werner Source|url=http://adsabs.harvard.edu/abs/2014ApJ...795..137R|journal=The Astrophysical Journal|volume=795|issue=2|pages=137|doi=10.1088/0004-637X/795/2/137|arxiv=1407.4472|bibcode=2014ApJ...795..137R|s2cid=119119172}}</ref><ref>{{Cite journal|last1=Sugimura|first1=Kazuyuki|last2=Omukai|first2=Kazuyuki|last3=Inoue|first3=Akio K.|date=2014-11-01|title=The critical radiation intensity for direct collapse black hole formation: dependence on the radiation spectral shape|url=http://adsabs.harvard.edu/abs/2014MNRAS.445..544S|journal=Monthly Notices of the Royal Astronomical Society|volume=445|issue=1|pages=544–553|doi=10.1093/mnras/stu1778|arxiv=1407.4039|bibcode=2014MNRAS.445..544S|s2cid=119257740}}</ref>

The previous conditions are necessary to avoid gas cooling and, hence, fragmentation of the primordial gas cloud. Unable to fragment and form stars, the gas cloud undergoes a gravitational collapse of the entire structure, reaching extremely large values of the matter density at the core, of the order of ~10<sup>7</sup> g/cm<sup>3</sup>.<ref name=":1">{{Cite journal|last1=Montero|first1=Pedro J.|last2=Janka|first2=Hans-Thomas|last3=Müller|first3=Ewald|date=2012-04-01|title=Relativistic Collapse and Explosion of Rotating Supermassive Stars with Thermonuclear Effects|url=http://adsabs.harvard.edu/abs/2012ApJ...749...37M|journal=The Astrophysical Journal|volume=749|issue=1|pages=37|doi=10.1088/0004-637X/749/1/37|arxiv=1108.3090|bibcode=2012ApJ...749...37M|s2cid=119098587}}</ref> At this density, the object undergoes a general relativistic instability,<ref name=":1" /> which leads to the formation of a black hole of a typical mass ~{{val|e=5|u={{Solar mass}}}}, and up to 1 million {{Solar mass}}. The occurrence of the general relativistic instability, as well as the absence of the intermediate stellar phase, led to the denomination of direct collapse black hole. In other words, these objects collapse directly from the primordial gas cloud, not from a stellar progenitor as prescribed in standard black hole models.<ref>{{Cite journal|last=Natarajan|first=Priyamvada|date=2018|title=The Puzzle of the First Black Holes|url=https://www.scientificamerican.com/article/the-puzzle-of-the-first-black-holes/|url-status=live|archive-url=https://web.archive.org/web/20180116173724/https://www.scientificamerican.com/article/the-puzzle-of-the-first-black-holes/ |archive-date=2018-01-16 |access-date=|journal=Scientific American|volume=318 |issue=2 |pages=24–29 |doi=10.1038/scientificamerican0218-24 |pmid=29337944 }}</ref>

A computer simulation reported in July 2022 showed that a halo at the rare convergence of strong, cold accretion flows can create massive black holes seeds without the need for ultraviolet backgrounds, supersonic streaming motions or even atomic cooling. Cold flows produced turbulence in the halo, which suppressed star formation. In the simulation, no stars formed in the halo until it had grown to 40 million solar masses at a redshift of 25.7 when the halo's gravity was finally able to overcome the turbulence; the halo then collapsed and formed two supermassive stars that died as DCBHs of {{val|31,000|fmt=commas}} and {{val|40,000|fmt=commas|u={{Solar mass}}}}.<ref>{{cite journal |title=Revealing the origin of the first supermassive black holes |journal=Nature |date=6 July 2022 |doi=10.1038/d41586-022-01560-y |pmid=35794378 |quote=State-of-the-art computer simulations show that the first supermassive black holes were born in rare, turbulent reservoirs of gas in the primordial Universe without the need for finely tuned, exotic environments — contrary to what has been thought for almost two decades.}}</ref><ref>{{cite web |title=Scientists discover how first quasars in universe formed |url=https://phys.org/news/2022-07-scientists-quasars-universe.html |website=phys.org |publisher=Provided by University of Portsmouth |access-date=2 August 2022 |date=6 July 2022}}</ref>

== Demography ==
Direct collapse black holes are generally thought to be extremely rare objects in the high-redshift Universe, because the three fundamental conditions for their formation (see above in section Formation) are challenging to be met all together in the same gas cloud.<ref>{{Cite journal|last1=Agarwal|first1=Bhaskar|last2=Dalla Vecchia|first2=Claudio|last3=Johnson|first3=Jarrett L.|last4=Khochfar|first4=Sadegh|last5=Paardekooper|first5=Jan-Pieter|date=2014-09-01|title=The First Billion Years project: birthplaces of direct collapse black holes|url=http://adsabs.harvard.edu/abs/2014MNRAS.443..648A|journal=Monthly Notices of the Royal Astronomical Society|volume=443|issue=1|pages=648–657|doi=10.1093/mnras/stu1112|arxiv=1403.5267|bibcode=2014MNRAS.443..648A|s2cid=119278181}}</ref><ref name=":3">{{Cite journal|last1=Habouzit|first1=Mélanie|last2=Volonteri|first2=Marta|last3=Latif|first3=Muhammad|last4=Dubois|first4=Yohan|last5=Peirani|first5=Sébastien|date=2016-11-01|title=On the number density of 'direct collapse' black hole seeds|url=http://adsabs.harvard.edu/abs/2016MNRAS.463..529H|journal=Monthly Notices of the Royal Astronomical Society|volume=463|issue=1|pages=529–540|doi=10.1093/mnras/stw1924|arxiv=1601.00557|bibcode=2016MNRAS.463..529H|s2cid=118409029}}</ref> Current cosmological simulations suggest that DCBHs could be as rare as only about 1 per cubic giga[[Astronomy:Parsec|parsec]] at redshift 15.<ref name=":3" /> The prediction on their number density is highly dependent on the minimum flux of Lyman–Werner photons required for their formation<ref>{{Cite journal|last1=Latif|first1=M. A.|last2=Bovino|first2=S.|last3=Grassi|first3=T.|last4=Schleicher|first4=D. R. G.|last5=Spaans|first5=M.|date=2015-01-01|title=How realistic UV spectra and X-rays suppress the abundance of direct collapse black holes|url=http://adsabs.harvard.edu/abs/2015MNRAS.446.3163L|journal=Monthly Notices of the Royal Astronomical Society|volume=446|issue=3|pages=3163–3177|doi=10.1093/mnras/stu2244|arxiv=1408.3061|bibcode=2015MNRAS.446.3163L|s2cid=119219917}}</ref> and can be as large as ~10<sup>7</sup> DCBHs per cubic gigaparsec in the most optimistic scenarios.<ref name=":3" />

== Detection ==
In 2016, a team led by [[Organization:Harvard University|Harvard University]] astrophysicist [[Biography:Fabio Pacucci|Fabio Pacucci]] identified the first two candidate direct collapse black holes,<ref name=":5">{{Cite journal|last1=Pacucci|first1=Fabio|last2=Ferrara|first2=Andrea|last3=Grazian|first3=Andrea|last4=Fiore|first4=Fabrizio|last5=Giallongo|first5=Emanuele|last6=Puccetti|first6=Simonetta|date=2016-06-01|title=First identification of direct collapse black hole candidates in the early Universe in CANDELS/GOODS-S|url=http://adsabs.harvard.edu/abs/2016MNRAS.459.1432P|journal=Monthly Notices of the Royal Astronomical Society|volume=459|issue=2|pages=1432–1439|doi=10.1093/mnras/stw725|arxiv=1603.08522|bibcode=2016MNRAS.459.1432P|s2cid=118578313}}</ref><ref>{{Cite web|title=The first Direct Collapse Black Hole candidates|url=https://www.fabiopacucci.com/impact/press-coverage/the-first-direct-collapse-black-hole-candidates/|access-date=2020-09-29|website=Fabio Pacucci|language=en-US}}</ref> using data from the [[Astronomy:Hubble Space Telescope|Hubble Space Telescope]] and the [[Astronomy:Chandra X-ray Observatory|Chandra X-ray Observatory]].<ref>{{Cite web|last=Northon|first=Karen|date=2016-05-24|title=NASA Telescopes Find Clues For How Giant Black Holes Formed So Quickly|url=http://www.nasa.gov/press-release/nasa-telescopes-find-clues-for-how-giant-black-holes-formed-so-quickly|access-date=2020-09-28|website=NASA}}</ref><ref>{{Cite web|title=Mystery of supermassive black holes might be solved|url=https://www.cbsnews.com/news/mystery-of-supermassive-black-holes-might-be-solved/|access-date=2020-09-28|website=www.cbsnews.com|date=25 May 2016 |language=en-US}}</ref><ref>{{Cite web|title=Mystery of Massive Black Holes May Be Answered by NASA Telescopes|url=https://abcnews.go.com/Technology/mystery-massive-black-holes-answered-nasa-telescopes/story?id=39364430|access-date=2020-09-28|website=ABC News|language=en}}</ref><ref>{{Cite news|last=Reynolds|first=Emily|date=2016-05-25|title=Hubble discovers clues to how supermassive black holes form|language=en-GB|magazine=Wired UK|url=https://www.wired.co.uk/article/hubble-space-telescope-black-holes|access-date=2020-09-28|issn=1357-0978}}</ref> The two candidates, both at redshift  <math>z > 6</math>, were found in the [[Astronomy:Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey|CANDELS]] [[Astronomy:Great Observatories Origins Deep Survey|GOODS-S]] field and matched the spectral properties predicted for this type of astrophysical sources.<ref>{{Cite journal|last1=Pacucci|first1=Fabio|last2=Ferrara|first2=Andrea|last3=Volonteri|first3=Marta|last4=Dubus|first4=Guillaume|date=2015-12-01|title=Shining in the dark: the spectral evolution of the first black holes|url=http://adsabs.harvard.edu/abs/2015MNRAS.454.3771P|journal=Monthly Notices of the Royal Astronomical Society|volume=454|issue=4|pages=3771–3777|doi=10.1093/mnras/stv2196|arxiv=1506.05299|bibcode=2015MNRAS.454.3771P|s2cid=119187129}}</ref> In particular, these sources are predicted to have a significant excess of [[Physics:Infrared|infrared]] radiation, when compared to other categories of sources at high redshift.<ref name=":5" /> Additional observations, in particular with the [[Astronomy:James Webb Space Telescope|James Webb Space Telescope]], will be crucial to investigate the properties of these sources and confirm their nature.<ref>{{Cite journal|last1=Natarajan|first1=Priyamvada|last2=Pacucci|first2=Fabio|last3=Ferrara|first3=Andrea|last4=Agarwal|first4=Bhaskar|last5=Ricarte|first5=Angelo|last6=Zackrisson|first6=Erik|last7=Cappelluti|first7=Nico|date=2017-04-01|title=Unveiling the First Black Holes With JWST:Multi-wavelength Spectral Predictions|journal=The Astrophysical Journal|volume=838|issue=2|pages=117|doi=10.3847/1538-4357/aa6330|arxiv=1610.05312|bibcode=2017ApJ...838..117N|s2cid=88502812 |doi-access=free }}</ref>

== Difference from primordial and stellar collapse black holes ==
A [[Astronomy:Primordial black hole|primordial black hole]] is the result of the direct collapse of energy, ionized matter, or both, during the [[Astronomy:Inflation (cosmology)|inflationary]] or [[Astronomy:Radiation-dominated era|radiation-dominated era]]s, while a direct collapse black hole is the result of the collapse of unusually dense and large regions of gas.<ref>{{cite journal |last1=Carr |first1=Bernard |last2=Kühnel |first2=Florian |title=Primordial Black Holes as Dark Matter: Recent Developments |journal=Annual Review of Nuclear and Particle Science |date=19 October 2020 |volume=70 |issue=1 |pages=355–394 |doi=10.1146/annurev-nucl-050520-125911 |arxiv=2006.02838 |bibcode=2020ARNPS..70..355C |s2cid=118475595 |url=https://www.annualreviews.org/doi/abs/10.1146/annurev-nucl-050520-125911 |access-date=4 September 2023 |language=en |issn=0163-8998}}</ref> Note that a black hole formed by the collapse of a [[Astronomy:Population III star|Population III star]] is not considered "direct" collapse.

== See also ==
* [[Astronomy:Quasi-star|Quasi-star]]
* [[Astronomy:UHZ1|UHZ1]]
* [[Astronomy:QSO J0313–1806|QSO J0313–1806]]
* [[Astronomy:GNz7q|GNz7q]]
* [[Astronomy:CEERS 1019 black hole|CEERS 1019 black hole]]

== References ==
{{Reflist}}

==Further reading==
* {{Cite journal|arxiv=1801.06649 |doi=10.1007/s12036-018-9513-x |title=Role of primordial black holes in the direct collapse scenario of supermassive black hole formation at high redshifts |date=2018 |last1=Pandey |first1=Kanhaiya L. |last2=Mangalam |first2=A. |journal=Journal of Astrophysics and Astronomy |volume=39 |issue=1 |page=9 |bibcode=2018JApA...39....9P |s2cid=255489158 }}
* {{Cite journal|arxiv=1803.06391 |doi=10.1088/1361-6633/aad6a5 |title=The route to massive black hole formation via merger-driven direct collapse: A review |date=2019 |last1=Mayer |first1=Lucio |last2=Bonoli |first2=Silvia |journal=Reports on Progress in Physics |volume=82 |issue=1 |page=016901 |pmid=30057369 |bibcode=2019RPPh...82a6901M |s2cid=51865966 }}
* {{Cite journal|arxiv=2003.10467 |doi=10.1093/mnras/staa763 |title=On monolithic supermassive stars |date=2020 |last1=Haemmerlé |first1=Lionel |last2=Heger |first2=Alexander |last3=Woods |first3=Tyrone E. |journal=Monthly Notices of the Royal Astronomical Society |volume=494 |issue=2 |pages=2236–2243 }}

{{Black holes}}

[[Category:Astronomy]]
[[Category:Astrophysics]]
[[Category:Physical cosmology]]
[[Category:Quasars|*]]
[[Category:Galaxies]]
[[Category:Black holes]]
[[Category:Supermassive black holes]]
[[Category:Theory of relativity]]

{{Sourceattribution|Direct collapse black hole}}