Self-interacting dark matter explained

In astrophysics and particle physics, self-interacting dark matter (SIDM) is an alternative class of dark matter particles which have strong interactions, in contrast to the standard cold dark matter model (CDM). SIDM was postulated in 2000^[1] as a solution to the core-cusp^{[2] [3] [4]} problem. In the simplest models of DM self-interactions, a Yukawa-type potential and a force carrier φ mediates between two dark matter particles.^[5] On galactic scales, DM self-interaction leads to energy and momentum exchange between DM particles. Over cosmological time scales this results in isothermal cores in the central region of dark matter haloes.

If the self-interacting dark matter is in hydrostatic equilibrium, its pressure and density follow:

\nabla P _{\chi/\rho} _{\chi} = \nabla \Phi _{\rm} = \nabla (\Phi _{\chi} + \Phi _{b)} where \Phi _{\chi} and \Phi _{b} are the gravitational potential of the dark matter and a baryon respectively. The equation naturally correlates the dark matter distribution to that of the baryonic matter distribution. With this correlation, the self-interacting dark matter can explain phenomena such as the Tully–Fisher relation.

Self-interacting dark matter has also been postulated as an explanation for the DAMA annual modulation signal.^{[6] [7] [8]} Moreover, it is shown that it can serve the seed of supermassive black holes at high redshift.^[9] SIDM may have originated in a so-called "Dark Big Bang".^[10]

A 2024 study found SIDM solves the "final-parsec problem".^[11]

See also

• MACS J0025.4-1222, astronomical observations that constrain DM self-interaction
• ESO 146-5, the core of Abell 3827 that was claimed as the first evidence of SIDM
• Strongly interacting massive particle (SIMP), proposed to explain cosmic ray data
• Lambda-CDM model

Further reading

• Book: Bertone , Gianfranco . Particle Dark Matter: Observations, Models and Searches . . 2010 . 762 . 978-0-521-76368-4. Particle Dark Matter . 2010pdmo.book.....B .
• What's the Matter? . May 2000 . George . Musser . . 282 . 5 . 24 . 10.1038/scientificamerican0500-24. 2000SciAm.282e..24M .
• Book: Lawrence , Krauss . Quintessence: The Search for Missing Mass in the Universe . . 2000 . 384 . 978-0465037414. Quintessence: The Search for Missing Mass in the Universe .

Notes and References

1. Spergel. David N.. Steinhardt. Paul J.. April 2000. Observational Evidence for Self-Interacting Cold Dark Matter. Physical Review Letters. en. 84. 17. 3760–3763. 10.1103/PhysRevLett.84.3760. 11019199. astro-ph/9909386. 2000PhRvL..84.3760S. 6669358. 0031-9007.
2. Moore. Ben. August 1994. Evidence against dissipation-less dark matter from observations of galaxy haloes. Nature. en. 370. 6491. 629–631. 10.1038/370629a0. 1994Natur.370..629M. 4325561. 0028-0836.
3. Oh. Se-Heon. de Blok. W. J. G.. Walter. Fabian. Brinks. Elias. Kennicutt. Robert C.. December 2008. High-Resolution Dark Matter Density Profiles of THINGS Dwarf Galaxies: Correcting for Noncircular Motions. The Astronomical Journal. en. 136. 6. 2761–2781. 10.1088/0004-6256/136/6/2761. 0810.2119. 2008AJ....136.2761O. 0004-6256. free.
4. Oh. Se-Heon. Hunter. Deidre A.. Brinks. Elias. Elmegreen. Bruce G.. Schruba. Andreas. Walter. Fabian. Rupen. Michael P.. Young. Lisa M.. Simpson. Caroline E.. Johnson. Megan C.. Herrmann. Kimberly A.. June 2015. High-resolution Mass Models of Dwarf Galaxies from LITTLE THINGS. The Astronomical Journal. en. 149. 6. 180. 10.1088/0004-6256/149/6/180. 1502.01281. 2015AJ....149..180O. 0004-6256. free.
5. Loeb. Abraham. Weiner. Neal. April 2011. Cores in Dwarf Galaxies from Dark Matter with a Yukawa Potential. Physical Review Letters. en. 106. 17. 171302. 10.1103/PhysRevLett.106.171302. 21635025. 1011.6374. 2011PhRvL.106q1302L. 0031-9007. free.
6. Saibal . Mitra . Has DAMA detected self-interacting dark matter? . Physical Review D . 71 . 12 . 121302 . 15 June 2005 . astro-ph/0409121 . 10.1103/PhysRevD.71.121302. 2005PhRvD..71l1302M . 31554326 .
7. News: Dark Matter May Feel a "Dark Force" That the Rest of the Universe Does Not . . Clara . Moskowitz . 20 April 2015.
8. Monthly Notices of the Royal Astronomical Society . 449 . 4P . 3393–3406 . June 2015 . The behaviour of dark matter associated with four bright cluster galaxies in the 10 kpc core of Abell 3827 . 10.1093/mnras/stv467. 1504.03388 . 2015MNRAS.449.3393M . Richard Massey . free . etal . commentary The Possible First Signs of Self-interacting Dark Matter
9. Seeding Supermassive Black Holes with Self-interacting Dark Matter: A Unified Scenario with Baryons . The Astrophysical Journal Letters . 2021 . 914 . L26 . Feng . W.-X. . Yu . H.-B. . Zhong . Y.-M. . 2. 10.3847/2041-8213/ac04b0 . 2010.15132 . free . 2021ApJ...914L..26F . "How a supermassive black hole originates: Study points to a seed black hole produced by a dark matter halo collapse." ScienceDaily, 16 June 2021.
10. . Dancing in the dark. The Economist. subscription. 9 March 2024.
11. Web site: Jonathan Gilbert . 2024-08-19 . 'Final parsec problem' that makes supermassive black holes impossible to explain could finally have a solution . 2024-08-20 . livescience.com . en.