Galactic_Center_GeV_excess

Galactic Center GeV excess

Galactic Center GeV excess

Unexplained gamma rays from the galactic center

The Galactic Center GeV Excess (GCE) is an unexpected surplus of gamma-ray radiation in the center of the Milky Way galaxy. This spherical source of radiation was first detected in 2009[1][2] by the Fermi Gamma-ray Space Telescope and is unexplained by direct observation.[3] Two percent of the gamma ray radiation in a 30° radius circle around the galactic center is attributed to the GCE. As of 2020, this excessive (and diffused) gamma-ray radiation is not well understood by astronomers.[4][5][6][7]

Gamma-ray radiation (greater than 1 Gev) detected over the entire sky; brighter areas are more radiation (five year study by the Fermi Gamma-ray Space Telescope: 2009–2013)

Some astronomers argue that self-annihilating dark matter (which is not otherwise known to radiate) may be the cause of the GCE, while others prefer a population of pulsars (which have not been observed) as the source.[8][3]

Astronomers have suggested that self-annihilating dark matter may be a dominant contributor to the GCE, based on analysis using non-Poissonian template fitting statistical methods,[5] wavelet methods,[7] and studies by other astronomers may support this idea.[9][10] More recently, in August 2020, other astronomers have reported that self-annihilating dark matter may not be the explanation for the GCE after all.[11][12] Other hypotheses include ties to a yet unseen population of millisecond pulsars[13][14] or young pulsars, burst events, the stellar population of the galactic bulge,[15] or the Milky Way's central supermassive black hole.[16]

See also

References

  1. [1]
    Goodenough, Lisa; Hooper, Dan (11 November 2009). "Possible Evidence For Dark Matter Annihilation In The Inner Milky Way From The Fermi Gamma Ray Space Telescope". arXiv:0910.2998 [hep-ph].
  2. [2]
    Wolchover, Natalie (3 March 2014). "Case for Dark Matter Signal Strengthens". Quanta Magazine. Retrieved 12 August 2021.
  3. [3]
    Cho, Adrian (12 November 2019). "Physicists revive hunt for dark matter in the heart of the Milky Way". Science | AAAS. Retrieved 31 March 2020.
  4. [4]
    Starr, Michelle (30 April 2019). "Something's Glowing at The Heart of Our Galaxy, But It May Not Be What We Thought". ScienceAlert.com. Retrieved 30 April 2019.
  5. [5]
    Leane, Rebecca K. & Slatyer, Tracy R. (17 April 2019). "Dark Matter Strikes Back at the Galactic Center". Phys. Rev. Lett. 123 (24): 241101. arXiv:1904.08430. doi:10.1103/PhysRevLett.123.241101. PMID 31922851. S2CID 210150636.
  6. [6]
    Fadelli, Ingrid (14 July 2020). "Could recently spotted dim point sources explain the galactic center excess (GCE)?". Phys.org. Retrieved 14 July 2020.
  7. [7]
    Zhong, Yi-Ming; McDermott, Samuel D.; Cholis, Ilias & Fox, Patrick J. (2020). "Testing the Sensitivity of the Galactic Center Excess to the Point Source Mask". Phys. Rev. Lett. 124 (23): 231103. arXiv:1911.12369. Bibcode:2020PhRvL.124w1103Z. doi:10.1103/PhysRevLett.124.231103. PMID 32603155. S2CID 208512856.
  8. [8]
    "Is there dark matter at the center of the Milky Way?". MIT News. 10 December 2019. Retrieved 4 May 2023.
  9. [9]
    Cuoco, Alessandro; et al. (4 March 2019). "Scrutinizing the evidence for dark matter in cosmic-ray antiprotons". Physical Review D. 99 (10): 103014. arXiv:1903.01472. Bibcode:2019PhRvD..99j3014C. doi:10.1103/PhysRevD.99.103014. S2CID 119333152.
  10. [10]
    Cholis, Ilias; et al. (6 March 2019). "A Robust Excess in the Cosmic-Ray Antiproton Spectrum: Implications for Annihilating Dark Matter". Physical Review D. 99 (10): 103026. arXiv:1903.02549. Bibcode:2019PhRvD..99j3026C. doi:10.1103/PhysRevD.99.103026. S2CID 118857451.
  11. [11]
    Starr, Michelle (28 August 2020). "There's a Strange Glow in The Centre of Our Galaxy, And It's Not What We Thought It Was". ScienceAlert.com. Retrieved 28 August 2020.
  12. [12]
    Abazajian, Kevork N.; et al. (4 August 2020). "Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center". Physical Review D. 102 (43012): 043012. arXiv:2003.10416. Bibcode:2020PhRvD.102d3012A. doi:10.1103/PhysRevD.102.043012.
  13. [13]
    Bartels, Richard; et al. (February 2016). "Strong Support for the Millisecond Pulsar Origin of the Galactic Center GeV Excess". Physical Review Letters. 116 (5). 051102. arXiv:1506.05104. Bibcode:2016PhRvL.116e1102B. doi:10.1103/PhysRevLett.116.051102. PMID 26894696. S2CID 217518922.
  14. [14]
    Gautam, Anuj; Crocker, Roland M.; Ferrario, Lilia; Ruiter, Ashley J.; Ploeg, Harrison; Gordon, Chris; Macias, Oscar (28 April 2022). "Millisecond pulsars from accretion-induced collapse as the origin of the Galactic Centre gamma-ray excess signal". Nature Astronomy. 6 (6): 703–707. arXiv:2106.00222. Bibcode:2022NatAs...6..703G. doi:10.1038/s41550-022-01658-3. ISSN 2397-3366. S2CID 235265843.
  15. [15]
    Macias, Oscar; et al. (12 March 2018). "Galactic bulge preferred over dark matter for the Galactic centre gamma-ray excess". Nature Astronomy. 2 (5): 387–392. arXiv:1611.06644. Bibcode:2018NatAs...2..387M. doi:10.1038/s41550-018-0414-3. S2CID 54936254.
  16. [16]
    Hooper, Dan & Goodenough, Lisa (21 March 2011). "Dark matter annihilation in the Galactic Center as seen by the Fermi Gamma Ray Space Telescope". Physics Letters B. 697 (5): 412–428. arXiv:1010.2752. Bibcode:2011PhLB..697..412H. doi:10.1016/j.physletb.2011.02.029. S2CID 118446838.

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