Sebonela-hōle sa Fermi se ile sa bona ka ho hlaka tlhahiso e feteletseng ea γ-ray bohareng ba sehlopha sa rōna sa linaleli sa lehae se neng se bonahala se se chitja ebile se bataletse. E bitsoa Galactic Center Excess (GCE), γ-ray ena e feteletseng ke pontšo e ka 'nang ea e-ba teng ea taba e lefifi e hlahang e le sehlahisoa sa ho ipolaea ha likaroloana tse kholo tse sebetsang ka thata (WIMPs), mokhethoa oa taba e lefifi. Leha ho le joalo, γ-ray e feteletseng e hlokometsoeng setsing sa galactic e ka boela ea bakoa ke li-millisecond pulsars tsa khale (MSPs). Ho fihlela joale, ho ne ho lumeloa hore morphology ea GCE ka lebaka la taba e lefifi (DM) e tla ba chitja. Phuputso ea morao-rao ea ketsiso e senola hore morphology ea gamma-ray ka lebaka la DM e ka ba e sa tsitsang le ho ba sephara. Sena se bolela hore ho timetsoa ha taba e lefifi (DM) le millisecond pulsars (MSPs) ho ka khoneha ka ho lekana. Mahlaseli a gamma a hlahisoang timetsong ea ntho e lefifi (DM) e ne e tla ba le matla a phahameng ka ho fetisisa a ka bang 0.1 tera-electron-volts (TeV). Libonela-hōle tse tloaelehileng tsa gamma-ray ha li khone ho bona ka ho toba li-photon tsena tse nang le matla a phahameng. Kahoo, netefatso ea mofuta o lefifi (DM) oa Galactic Center Excess (GCE) e ka khonahala ha ho phetheloa lithuto tsa tera γ-ray observatory tse kang Cherenkov Telescope Array Observatory (CTAO) le Southern Wide-field Gamma-ray Observatory (SWGO).
Pale ea taba e lefifi e qalile ka 1933 ha Fritz Zwicky a hlokomela hore lihlopha tsa linaleli tse tsamaeang ka potlako Sehlopheng sa Coma ha li khone ho tšoarana 'me tsa lula li tsitsitse ntle le ho ba teng ha lintho tse ling tse sa bonahaleng empa li na le matla a khoheli a lekaneng ho thibela lihlopha tsa linaleli hore li se ke tsa arohana. O ile a qapa lentsoe “lefifi” ho bolela ntho e joalo e sa bonahaleng. Lilemong tsa bo-1960, Vera Rubin o ile a kenya letsoho kutloisisong ea rona ea taba e lefifi. O ile a hlokomela hore linaleli tse mathōkong a ka ntle a Andromeda le lihlopha tse ling tsa linaleli li ne li potoloha ka lebelo le lekanang le lebelo la linaleli ho ea bohareng. Bakeng sa kakaretso e fanoeng ea lintho tsohle tse hlokometsoeng, sehlopha sa linaleli se ne se lokela hore ebe se ile sa fofa ka thōko ho neng ho hlokahala hore ho be le lintho tse ling tse sa bonahaleng tse bolokang lihlopha tsa linaleli le ho li etsa hore li bilike ka lebelo le phahameng. Litekanyo tsa hae tsa ho potoloha ha molala oa linaleli oa Andromeda li ile tsa fana ka bopaki ba pele ba taba e lefifi.
Joale rea tseba hore taba e lefifi ha e sebelisane le khanya kapa matla a motlakase. Ha e monye, ha e bonese kapa e ntša khanya kapa mahlaseli afe kapa afe a motlakase 'me ha e bonahale ka hona e bitsoa lefifi. Empa e bokellana ka matla a khoheli 'me e na le phello ea matla a khoheli holim'a taba e tloaelehileng, 'me ke ka tsela ena boteng ba eona sebakeng se atisang ho hlalosoa. Lihlopha tsa linaleli li kopantsoe hammoho ka teka-tekano ke phello ea matla a khoheli ea ntho e lefifi e etsang hoo e ka bang 26.8% ea matla a mangata a bokahohleng athe bokahohle bo bonahalang bo kenyeletsang lintho tse tloaelehileng tsa baryonic tseo kaofela re entsoeng ka tsona li etsa feela 4.9% ea bokahohle. Karolo e setseng ea 68.3% ea matla a mangata a bokahohleng ke matla a lefifi.
Ha ho tsejoe hore na taba e lefifi ke efe. Ha ho na likaroloana tsa motheo ho Mohlala o Motle e na le thepa e hlokahalang ho ba ntho e lefifi. Mohlomong, "li-supersymmetric particles" tse inahaneloang tseo e leng balekane ba likaroloana tsa Mohlala o Tloaelehileng li etsa taba e lefifi. Mohlomong ho na le lefatše le tšoanang la taba e lefifi. WIMPs (Weakly Interacting Massive Particles), li-axion, kapa sterile neutrinos ke likaroloana tse inahaneloang tse fetang Moetso o Tloaelehileng tse etellang pele bonkgetheng. Leha ho le joalo, ha ho katleho e kileng ea finyelloa ho sibolloeng ha likaroloana tse joalo.
Ho na le merero e mengata (joalo ka Teko ea XENON, Morero oa DarkSide-20k, EURECA Rxperiment, 'me RES-NOVA) e ntse e tsoela pele bakeng sa ho lemoha ka ho toba likaroloana tse lefifi. Hangata tsena ke li-detectors tsa khase tse nang le metsi kapa li-cryogenic tse etselitsoeng ho bona matšoao a fokolang a amanang le tšebelisano ea likaroloana tse lefifi. Leha ho le joalo, leha ho na le mekhoa e mengata e mecha, ha ho projeke e khonneng ho bona ka kotloloho karolo efe kapa efe e lefifi.
Bakeng sa bopaki bo sa tobang ba taba e lefifi, motho a ka sheba litlamorao tsa matla a khoheli a ntho e lefifi, joalo ka ha Fritz Zwicky le Vera Rubin ba ile ba etsa ho sibolla taba e lefifi ka ho ithuta kamoo lihlopha tsa linaleli li kopantsoeng hammoho le hoja li na le lebelo le phahameng ka mokhoa o sa lekanyetsoang bakeng sa taba e tloaelehileng e hlokometsoeng. Matla a khoheli a lense (ho kobeha ha leseli) le litlamorao tsa motsamao oa linaleli sepakapakeng le tsona li ka fana ka bopaki bo sa tobang ba boteng ba ntho e lefifi. Ho feta moo, lihlahisoa tsa timetso (tse kang gamma-ray, neutrinos, le cosmic ray) tse entsoeng ha likaroloana tse lefifi li thulana sebakeng li ka boela tsa bontša boteng ba ntho e lefifi. Sebaka se seng se joalo seo ho sona ho ileng ha boleloa esale pele hore lintho tse lefifi li thehiloe lihlahisoa tsa ho timetsoa ha likaroloana tse lefifi ke setsi sa sehlopha sa linaleli sa lehae sa rōna sa Milky Way.
Ho fumanoa lintho tse lefifi bohareng ba sehlopha sa linaleli sa lehae sa rona sa Milky Way
Ho ne ho e-na le matšoao a khanya e feteletseng ea microwave bohareng ba Milky Way (MW). Khanya e feteletseng e ne e reriloe hore e be ka lebaka la tlhahiso ea synchrotron e tsoang ho lielektrone tsa relativistic le li-positron tse hlahisitsoeng ho timetsong ea taba e lefifi ea WIMP, ka hona ho ile ha boleloa esale pele lets'oao le atolositsoeng la γ-ray matleng a matla a fihlang ho makholo a 'maloa a GeV. Ka mor'a moo, Fermi-Large Area Telescope (LAT) e ile ea lemoha letšoao la γ-ray le neng le khetholloa e le Galactic Center Excess (GCE). Haufinyane, ho ile ha hlokomeloa hore Galactic Center Excess (GCE) e ka boela ea bakoa ke linaleli tsa khale tsa neutron (millisecond pulsars). Ho ne ho nahanoa hore morphology ea GCE e tla ba ea bohlokoa - GCE e bōpehileng joaloka spherical e ne e tla ba sesupo sa tlhahiso ea γ-ray ho tloha timetsong ea likaroloana tse lefifi (DM) ha morpholoji e bataletseng ea GCE e ne e tla fana ka maikutlo a tlhahiso ea γ-ray ho tloha millisecond pulsars (MSP).
Teko e batsi ea setsi sa linaleli sa Milky Way ke Fermi-Large Area Telescope (LAT) e senotse asphericity e bataletseng. Ka tloaelo, motho a ka amahanya asphericity e hlokometsoeng ho linaleli tsa khale (MSP) leha ho le joalo phuputso ea morao-rao e phatlalalitsoeng ka la 16 Mphalane 2025 e fihletse qeto ea hore li-morphology tsa GCE tse boletsoeng esale pele ke linaleli tsa khale (MSP) le mefuta ea timetso e lefifi (DM) ha li khethollehe.
Ho ithuta kabo ea taba e lefifi, bafuputsi ba ile ba etsa papiso ea morphology ea MW (Milky Way) -joaloka melala ea linaleli. Ba fumane hore li-halos tse lefifi tse pota-potileng lihlopha tsa linaleli hammoho le libaka tse pota-potileng libaka tse bohareng tsa lihlopha tsa linaleli ha se hangata li leng chitja joalokaha ho nahanoa ka mohlala oa anisotropic. Ho e-na le hoo, tlhahlobo e ile ea bontša khakanyo e bataletseng ea ho teteana ha lintho tse lefifi bakeng sa lihlopha tsohle tsa linaleli. Kabo ena ea "non-axisymmetric dark matter" (DM) e bonts'itsoeng hape ke ho kopanya nalane ea sehlopha sa linaleli sa Milky Way lilemong tsa pele tse libilione tse tharo nalaneng ea bokahohle. Morpholoji e hlokometsoeng ea GCE e batalalitsoe sebakeng se bohareng, seo ka kakaretso ho nahanoang hore ke tšobotsi ea kabo ea linaleli tsa khale (MSP). Phuputso e ncha e bontšitse hore taba e lefifi (DM) e hlahisa kabo e tšoanang ea mabokose. Kahoo, ho timetsoa ka bobeli ha taba e lefifi (DM) le millisecond pulsars (MSPs) hypotheses bakeng sa GCE e hlokometsoeng li ka khoneha ka ho lekana.
Hore na GCE e hlokometsoeng e bakoa ke taba e lefifi (DM) kapa ka lebaka la millisecond pulsars (MSPs) e tla tsejoa ha libaka tsa γ-ray tse kang Cherenkov Telescope Array Observatory (CTAO) le Southern Wide-field Gamma-ray Observatory (SWGO) li qeta lithuto tsa tsona tsa tera-gamma ray nakong e tlang. Mahlaseli a gamma a hlahisoang e le sehlahisoa sa timetso ea ntho e lefifi (DM) setsing sa galactic e tla ba li-photon tse matla haholo tse nang le matla a phahameng haholo a ka bang 0.1 tera-electron-volts (TeV). Libonela-hōle tse tloaelehileng tsa gamma-ray ha li khone ho bona ka ho toba li-photon tsena tse nang le matla a phahameng. Mahlaseli a Tera-gamma e tla ba sepheo sa bohlokoa bakeng sa libaka tsa kamoso tsa γ-ray tse kang CTAO le SWGO.
Boithuto bona ke mohato oa pele oa ho lemoha ntho e lefifi sebakeng ka lihlahisoa tsa eona tsa timetso leha ho le joalo ho ba teng ha ntho e lefifi setsing sa galactic ho tla hloka netefatso ea matla a phahameng a γ-ray observatories joalo ka CTAO kapa SWGO nakong e tlang. Khatelo-pele e kholo ho saense ea taba e lefifi e ka ba ho lemoha ka ho toba karolo efe kapa efe ea DM.
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References:
- Hochberg, Y., Kahn, YF, Leane, RK et al. Mekhoa e mecha ea ho lemoha lintho tse lefifi. Nat Rev Phys 4, 637–641 (2022). https://doi.org/10.1038/s42254-022-00509-4
- Misiaszeka M. le Rossib N. 2024. Ho lemoha ka ho toba taba e lefifi: tlhahlobo ea bohlokoa. Symmetry 2024, 16(2), 201; DOI: https://doi.org/10.3390/sym16020201
- Instituto de Física Corpuscular. Ho batla taba e lefifi: mokhoa o mocha oa ho bona tse sa bonahaleng. 22 August 2025. E fumaneha ho https://webific.ific.uv.es/web/en/content/search-dark-matter-new-approach-detecting-invisible
- Muru MM, et al 2025. Fermi-LAT Galactic Center Excess Morphology of Dark Matter in Simulations of the Milky Way Galaxy. Mangolo a Tlhahlobo ea 'Mele. 135, 161005. E phatlalalitsoe ka la 16 Mphalane 2025. DOI: https://doi.org/10.1103/g9qz-h8wd . Phetolelo ea Preprint ho arXiv. E hlahisitsoe ka la 8 Phato 2025. DOI: https://doi.org/10.48550/arXiv.2508.06314
- Univesithi ea Johns Hopkins. Litaba - Ho khanya ho makatsang ka tsela ea milky e ka ba bopaki ba taba e lefifi. E ngotsoe ka la 16 Mphalane 2025. E fumaneha ho https://hub.jhu.edu/2025/10/16/mysterious-glow-in-milky-way-dark-matter/
- Setsi sa Leibniz sa Astrophysics. Litaba - Milky Way e bonts'a gamma ray e feteletseng ka lebaka la ho timetsoa ha lintho tse lefifi. E ngotsoe 17 October 2025. E fumaneha ho https://www.aip.de/en/news/milkyway-gammaray-darkmatter-annihilation/
- Fermi Gamma-ray Space Telescope. E fumaneha ho https://science.nasa.gov/mission/fermi/
- Cherenkov Telescope Array Observatory (CTAO). E fumaneha ho https://www.ctao.org/emission-to-discovery/science/
- Sebaka sa Southern Wide-field Gamma-ray Observatory (SWGO). E fumaneha ho https://www.swgo.org/SWGOWiki/doku.php?id=swgo_rel_pub
- Tartu Observatory. Lehlakore le lefifi la Bokahohle. E fumaneha ho https://kosmos.ut.ee/en/dark-side-of-the-universe
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, this excess γ-ray is a possible signature of dark matter arising as a product of self-annihilations of weakly interacting massive particles (WIMPs), a dark matter particle candidate. However, the excess γ-ray observed at the galactic centre may also be due to old millisecond pulsars (MSPs). Hitherto, it was held that the morphology GCE due to dark matter (DM) would be spherical. A recent simulation study reveals that gamma-ray morphology due to DM could be significantly nonspherical and flattened. This means both dark matter (DM) annihilations and millisecond pulsars (MSPs) hypotheses for the observed GCE are equally possible. The gamma rays produced in the annihilation of dark matter (DM) would have an extremely high energy level of approximately 0.1 tera-electron-volts (TeV). The standard gamma-ray telescopes cannot detect these high-energy photons directly. Hence, confirmation of dark matter (DM) model of Galactic Centre Excess (GCE) would be possible upon completion of studies by the tera γ-ray observatories like CTAO and SWGO.){kind=link}