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Direct collapse black hole

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Artist's impression for the formation of a massive black hole seed via the direct black hole channel.[1]

Direct collapse black holes (DCBHs) are high-mass black hole seeds that form from the direct collapse of a large amount of material.[2][3][4][5] They putatively formed within the redshift range z=15–30,[6] when the Universe was about 100–250 million years old. Unlike seeds formed from the first population of stars (also known as Population III stars), direct collapse black hole seeds are formed by a direct, general relativistic instability. They are very massive, with a typical mass at formation of ~105 M.[3][7] This category of black hole seeds was originally proposed theoretically to alleviate the challenge in building supermassive black holes already at redshift z~7, as numerous observations to date have confirmed.[1][8][9][10][11]

Formation

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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 ~105 M, but spanning between 104 M and 106 M. The environmental physical conditions to form a DCBH (as opposed to a cluster of stars) are the following:[3][4]

  1. Metal-free gas (gas containing only hydrogen and helium).
  2. Atomic-cooling gas.
  3. Sufficiently large flux of Lyman–Werner photons, in order to destroy hydrogen molecules, which are very efficient gas coolants.[12][13]

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 high matter density at its core, on the order of ~107 g/cm3.[14] At this density, the object undergoes a general relativistic instability,[14] which leads to the formation of a black hole of a typical mass ~105 M, and up to 1 million M. 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.[15]

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 31,000 and 40,000 M.[16][17]

Demography

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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.[18][19] Current cosmological simulations suggest that DCBHs could be as rare as only about 1 per cubic gigaparsec at redshift 15.[19] The prediction on their number density is highly dependent on the minimum flux of Lyman–Werner photons required for their formation[20] and can be as large as ~107 DCBHs per cubic gigaparsec in the most optimistic scenarios.[19]

Detection

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In 2016, a team led by Harvard University astrophysicist Fabio Pacucci identified the first two candidate direct collapse black holes,[21][22] using data from the Hubble Space Telescope and the Chandra X-ray Observatory.[23][24][25][26] The two candidates, both at redshift , were found in the CANDELS GOODS-S field and matched the spectral properties predicted for this type of astrophysical sources.[27] In particular, these sources are predicted to have a significant excess of infrared radiation, when compared to other categories of sources at high redshift.[21] Additional observations, in particular with the James Webb Space Telescope, will be crucial to investigate the properties of these sources and confirm their nature.[28]

Difference from primordial and stellar collapse black holes

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A primordial black hole is the result of the direct collapse of energy, ionized matter, or both, during the inflationary or radiation-dominated eras, while a direct collapse black hole is the result of the collapse of unusually dense and large regions of gas.[29] Note that a black hole formed by the collapse of a Population III star is not considered "direct" collapse.

See also

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References

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  1. ^ a b "NASA Telescopes Find Clues For How Giant Black Holes Formed So Quickly". Press Room. Chandra X-ray Observatory. 24 May 2016. Retrieved 2020-08-27.
  2. ^ Loeb, Abraham; Rasio, Frederic A. (1994-09-01). "Collapse of primordial gas clouds and the formation of quasar black holes". The Astrophysical Journal. 432: 52–61. arXiv:astro-ph/9401026. Bibcode:1994ApJ...432...52L. doi:10.1086/174548. S2CID 17042784.
  3. ^ a b c Bromm, Volker; Loeb, Abraham (2003-10-01). "Formation of the First Supermassive Black Holes". The Astrophysical Journal. 596 (1): 34–46. arXiv:astro-ph/0212400. Bibcode:2003ApJ...596...34B. doi:10.1086/377529. S2CID 14419385.
  4. ^ a b Lodato, Giuseppe; Natarajan, Priyamvada (2006-10-01). "Supermassive black hole formation during the assembly of pre-galactic discs". Monthly Notices of the Royal Astronomical Society. 371 (4): 1813–1823. arXiv:astro-ph/0606159. Bibcode:2006MNRAS.371.1813L. doi:10.1111/j.1365-2966.2006.10801.x. S2CID 13448595.
  5. ^ Siegel, Ethan. "'Direct Collapse' Black Holes May Explain Our Universe's Mysterious Quasars". Forbes. Retrieved 2020-08-27.
  6. ^ Yue, Bin; Ferrara, Andrea; Salvaterra, Ruben; Xu, Yidong; Chen, Xuelei (2014-05-01). "The brief era of direct collapse black hole formation". Monthly Notices of the Royal Astronomical Society. 440 (2): 1263–1273. arXiv:1402.5675. Bibcode:2014MNRAS.440.1263Y. doi:10.1093/mnras/stu351. S2CID 119275449.
  7. ^ Rees, Martin J.; Volonteri, Marta (2007-04-01). "Massive black holes: formation and evolution". Black Holes from Stars to Galaxies – Across the Range of Masses. 238: 51–58. arXiv:astro-ph/0701512. Bibcode:2007IAUS..238...51R. doi:10.1017/S1743921307004681. S2CID 14844338.
  8. ^ Bañados, Eduardo; Venemans, Bram P.; Mazzucchelli, Chiara; Farina, Emanuele P.; Walter, Fabian; Wang, Feige; Decarli, Roberto; Stern, Daniel; Fan, Xiaohui; Davies, Frederick B.; Hennawi, Joseph F. (2018-01-01). "An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5". Nature. 553 (7689): 473–476. arXiv:1712.01860. Bibcode:2018Natur.553..473B. doi:10.1038/nature25180. PMID 29211709. S2CID 205263326.
  9. ^ Fan, Xiaohui; Narayanan, Vijay K.; Lupton, Robert H.; Strauss, Michael A.; Knapp, Gillian R.; Becker, Robert H.; White, Richard L.; Pentericci, Laura; Leggett, S. K.; Haiman, Zoltán; Gunn, James E. (2001-12-01). "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". The Astronomical Journal. 122 (6): 2833–2849. arXiv:astro-ph/0108063. Bibcode:2001AJ....122.2833F. doi:10.1086/324111. S2CID 119339804.
  10. ^ Yang, Jinyi; Wang, Feige; Fan, Xiaohui; Hennawi, Joseph F.; Davies, Frederick B.; Yue, Minghao; Banados, Eduardo; Wu, Xue-Bing; Venemans, Bram; Barth, Aaron J.; Bian, Fuyan (2020-07-01). "Poniua'ena: A Luminous z = 7.5 Quasar Hosting a 1.5 Billion Solar Mass Black Hole". The Astrophysical Journal Letters. 897 (1): L14. arXiv:2006.13452. Bibcode:2020ApJ...897L..14Y. doi:10.3847/2041-8213/ab9c26. S2CID 220042206.
  11. ^ "Monster Black Hole Found in the Early Universe". Gemini Observatory. 2020-06-24. Retrieved 2020-09-06.
  12. ^ Regan, John A.; Johansson, Peter H.; Wise, John H. (2014-11-01). "The Direct Collapse of a Massive Black Hole Seed under the Influence of an Anisotropic Lyman–Werner Source". The Astrophysical Journal. 795 (2): 137. arXiv:1407.4472. Bibcode:2014ApJ...795..137R. doi:10.1088/0004-637X/795/2/137. S2CID 119119172.
  13. ^ Sugimura, Kazuyuki; Omukai, Kazuyuki; Inoue, Akio K. (2014-11-01). "The critical radiation intensity for direct collapse black hole formation: dependence on the radiation spectral shape". Monthly Notices of the Royal Astronomical Society. 445 (1): 544–553. arXiv:1407.4039. Bibcode:2014MNRAS.445..544S. doi:10.1093/mnras/stu1778. S2CID 119257740.
  14. ^ a b Montero, Pedro J.; Janka, Hans-Thomas; Müller, Ewald (2012-04-01). "Relativistic Collapse and Explosion of Rotating Supermassive Stars with Thermonuclear Effects". The Astrophysical Journal. 749 (1): 37. arXiv:1108.3090. Bibcode:2012ApJ...749...37M. doi:10.1088/0004-637X/749/1/37. S2CID 119098587.
  15. ^ Natarajan, Priyamvada (2018). "The Puzzle of the First Black Holes". Scientific American. 318 (2): 24–29. doi:10.1038/scientificamerican0218-24. PMID 29337944. Archived from the original on 2018-01-16.
  16. ^ "Revealing the origin of the first supermassive black holes". Nature. 6 July 2022. doi:10.1038/d41586-022-01560-y. PMID 35794378. 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.
  17. ^ "Scientists discover how first quasars in universe formed". phys.org. Provided by University of Portsmouth. 6 July 2022. Retrieved 2 August 2022.
  18. ^ Agarwal, Bhaskar; Dalla Vecchia, Claudio; Johnson, Jarrett L.; Khochfar, Sadegh; Paardekooper, Jan-Pieter (2014-09-01). "The First Billion Years project: birthplaces of direct collapse black holes". Monthly Notices of the Royal Astronomical Society. 443 (1): 648–657. arXiv:1403.5267. Bibcode:2014MNRAS.443..648A. doi:10.1093/mnras/stu1112. S2CID 119278181.
  19. ^ a b c Habouzit, Mélanie; Volonteri, Marta; Latif, Muhammad; Dubois, Yohan; Peirani, Sébastien (2016-11-01). "On the number density of 'direct collapse' black hole seeds". Monthly Notices of the Royal Astronomical Society. 463 (1): 529–540. arXiv:1601.00557. Bibcode:2016MNRAS.463..529H. doi:10.1093/mnras/stw1924. S2CID 118409029.
  20. ^ Latif, M. A.; Bovino, S.; Grassi, T.; Schleicher, D. R. G.; Spaans, M. (2015-01-01). "How realistic UV spectra and X-rays suppress the abundance of direct collapse black holes". Monthly Notices of the Royal Astronomical Society. 446 (3): 3163–3177. arXiv:1408.3061. Bibcode:2015MNRAS.446.3163L. doi:10.1093/mnras/stu2244. S2CID 119219917.
  21. ^ a b Pacucci, Fabio; Ferrara, Andrea; Grazian, Andrea; Fiore, Fabrizio; Giallongo, Emanuele; Puccetti, Simonetta (2016-06-01). "First identification of direct collapse black hole candidates in the early Universe in CANDELS/GOODS-S". Monthly Notices of the Royal Astronomical Society. 459 (2): 1432–1439. arXiv:1603.08522. Bibcode:2016MNRAS.459.1432P. doi:10.1093/mnras/stw725. S2CID 118578313.
  22. ^ "The first Direct Collapse Black Hole candidates". Fabio Pacucci. Retrieved 2020-09-29.
  23. ^ Northon, Karen (2016-05-24). "NASA Telescopes Find Clues For How Giant Black Holes Formed So Quickly". NASA. Retrieved 2020-09-28.
  24. ^ "Mystery of supermassive black holes might be solved". www.cbsnews.com. 25 May 2016. Retrieved 2020-09-28.
  25. ^ "Mystery of Massive Black Holes May Be Answered by NASA Telescopes". ABC News. Retrieved 2020-09-28.
  26. ^ Reynolds, Emily (2016-05-25). "Hubble discovers clues to how supermassive black holes form". Wired UK. ISSN 1357-0978. Retrieved 2020-09-28.
  27. ^ Pacucci, Fabio; Ferrara, Andrea; Volonteri, Marta; Dubus, Guillaume (2015-12-01). "Shining in the dark: the spectral evolution of the first black holes". Monthly Notices of the Royal Astronomical Society. 454 (4): 3771–3777. arXiv:1506.05299. Bibcode:2015MNRAS.454.3771P. doi:10.1093/mnras/stv2196. S2CID 119187129.
  28. ^ Natarajan, Priyamvada; Pacucci, Fabio; Ferrara, Andrea; Agarwal, Bhaskar; Ricarte, Angelo; Zackrisson, Erik; Cappelluti, Nico (2017-04-01). "Unveiling the First Black Holes With JWST:Multi-wavelength Spectral Predictions". The Astrophysical Journal. 838 (2): 117. arXiv:1610.05312. Bibcode:2017ApJ...838..117N. doi:10.3847/1538-4357/aa6330. S2CID 88502812.
  29. ^ Carr, Bernard; Kühnel, Florian (19 October 2020). "Primordial Black Holes as Dark Matter: Recent Developments". Annual Review of Nuclear and Particle Science. 70 (1): 355–394. arXiv:2006.02838. Bibcode:2020ARNPS..70..355C. doi:10.1146/annurev-nucl-050520-125911. ISSN 0163-8998. S2CID 118475595. Retrieved 4 September 2023.

Further reading

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