Fermi telescope ua kom huv si soj ntsuam ntawm ntau tshaj γ-ray emission nyob rau hauv nruab nrab ntawm peb lub tsev galaxy uas tshwm tsis-spherical thiab flattened. Hu ua Galactic Center Excess (GCE), qhov ntau tshaj γ-duab tshav yog qhov ua tau kos npe ntawm cov teeb meem tsaus ntuj uas tshwm sim los ntawm cov khoom ntawm nws tus kheej rhuav tshem ntawm cov tsis muaj zog cuam tshuam loj heev (WIMPs), cov teeb meem tsaus nti particle neeg sib tw. Txawm li cas los xij, qhov tshaj γ-ray pom ntawm lub chaw galactic kuj tseem yog vim cov qub millisecond pulsars (MSPs). Txog tam sim no, nws tau tuav tias GCE morphology vim qhov teeb meem tsaus nti (DM) yuav yog kheej kheej. Ib txoj kev tshawb fawb simulation tsis ntev los no qhia tau tias gamma-ray morphology vim DM tuaj yeem ua qhov tsis zoo thiab ua kom zoo. Qhov no txhais tau hais tias ob qho tib si tsaus nti (DM) kev puas tsuaj thiab millisecond pulsars (MSPs) kev xav rau GCE tau pom zoo sib npaug. Cov gamma rays uas tsim nyob rau hauv lub annihilation ntawm cov teeb meem tsaus nti (DM) yuav muaj ib tug tsis tshua muaj zog theem ntawm kwv yees li 0.1 tera-electron-volts (TeV). Tus qauv gamma-ray telescopes tsis tuaj yeem ntes cov duab hluav taws xob siab ncaj qha. Yog li, kev pom zoo ntawm cov teeb meem tsaus ntuj (DM) qauv ntawm Galactic Center Excess (GCE) yuav ua tau tom qab ua tiav cov kev tshawb fawb los ntawm tera γ-ray observatories xws li Cherenkov Telescope Array Observatory (CTAO) thiab Southern Wide-field Gamma-ray Observatory (SWGO).
Zaj dab neeg ntawm cov teeb meem tsaus ntuj pib thaum xyoo 1933 thaum Fritz Zwicky pom tias cov galaxies nrawm nrawm hauv Coma Cluster tsis tuaj yeem tuav ua ke thiab nyob ruaj khov yam tsis muaj cov teeb meem ntxiv uas pom tsis tau tab sis ua kom muaj txiaj ntsig txaus los tiv thaiv galaxies los ntawm kev poob. Nws tau sau lo lus "dub teeb meem" los hais txog qhov tsis pom qhov teeb meem. Hauv xyoo 1960, Vera Rubin tau ua ib qho kev txhawb nqa rau peb txoj kev nkag siab txog qhov tsaus ntuj. Nws tau sau tseg tias cov hnub qub nyob rau sab nrauv ntawm Andromeda thiab lwm lub galaxies tau hloov nrog lub nrawm nrawm raws li qhov nrawm ntawm cov hnub qub mus rau qhov chaw. Rau qhov muab tag nrho cov teeb meem pom, lub galaxy yuav tsum tau ya sib nrug los ntawm qhov tseem ceeb ntawm qee qhov teeb meem tsis pom ntxiv uas ua kom cov galaxies ua ke thiab ua rau lawv tig mus rau hauv kev kub ceev. Nws kev ntsuas ntawm kev sib hloov nkhaus ntawm Andromeda galaxy muab pov thawj ntxov tshaj plaws ntawm cov teeb meem tsaus.
Tam sim no peb paub tias qhov tsaus ntuj tsis cuam tshuam nrog lub teeb lossis lub zog hluav taws xob. Nws tsis nqus, xav txog lossis tawm lub teeb lossis lwm yam hluav taws xob hluav taws xob thiab tsis pom qhov no hu ua tsaus. Tab sis nws pawg gravitationally thiab muaj gravitational nyhuv ntawm cov teeb meem zoo tib yam, thiab qhov no yog li cas nws muaj nyob rau hauv qhov chaw feem ntau inferred. Galaxies tau tuav ua ke nyob rau hauv qhov sib npaug los ntawm qhov gravitational nyhuv ntawm cov teeb meem tsaus ntuj uas muaj ntau npaum li 26.8% ntawm lub zog loj ntawm lub ntiaj teb whereas tag nrho lub ntiaj teb observable nrog rau tag nrho cov baryonic zoo tib yam teeb meem uas peb txhua tus yog tsim los ntawm tsuas yog 4.9% ntawm lub ntug. Qhov seem 68.3% ntawm lub zog loj ntawm lub ntiaj teb yog lub zog tsaus nti.
Tsis paub tias qhov tsaus ntuj tiag tiag yog dab tsi. Tsis muaj cov ntsiab lus tseem ceeb hauv cov Txheem Qauv muaj cov khoom xav tau los ua qhov tsaus ntuj. Tej zaum, hypothetical "supersymmetric hais" uas yog cov koom tes rau cov hais nyob rau hauv tus qauv qauv ua rau tsaus teeb meem. Tej zaum muaj lub ntiaj teb sib npaug ntawm cov teeb meem tsaus ntuj. WIMPs (Weakly Interacting Massive Particles), axions, los yog sterile neutrinos yog hypothesized hais tshaj tus qauv qauv uas yog thawj tus neeg sib tw. Txawm li cas los xij, tseem tsis tau muaj kev vam meej hauv kev tshawb nrhiav cov khoom zoo li no.
Muaj ntau qhov project (xws li Kev sim XENON, DarkSide-20k Project, EURECA Rxperiment, thiab RES-NOVA) tam sim no tab tom nrhiav ncaj qha ntawm cov teeb meem tsaus ntuj. Cov no feem ntau yog cov kua hluav taws xob tsis zoo los yog cov khoom siv cryogenic uas tau tsim los xyuas cov teeb meem tsis pom kev los ntawm kev cuam tshuam ntawm cov teeb meem tsaus ntuj. Txawm li cas los xij, txawm hais tias muaj ntau txoj hauv kev tshiab, tsis muaj qhov project tau ncaj qha mus ntes cov teeb meem tsaus ntuj tsis tau.
Rau cov pov thawj tsis ncaj ncees ntawm cov teeb meem tsaus ntuj, ib tus tuaj yeem nrhiav qhov cuam tshuam ntawm cov teeb meem tsaus ntuj, raws li Fritz Zwicky thiab Vera Rubin tau tshawb pom qhov teeb meem tsaus ntuj los ntawm kev kawm seb galaxies tuav ua ke txawm tias muaj qhov nrawm tsis sib xws rau qhov pom qhov teeb meem. Cov teebmeem gravitational ntawm lo ntsiab muag (khoov ntawm lub teeb) thiab cov teebmeem ntawm kev txav ntawm cov hnub qub hauv qhov chaw tuaj yeem muab pov thawj tsis ncaj qha ntawm qhov muaj qhov tsaus ntuj. Tsis tas li ntawd, cov khoom puas tsuaj (xws li gamma-rays, neutrinos, thiab cosmic rays) tsim thaum cov teeb meem tsaus ntuj sib tsoo nrog ib leeg hauv qhov chaw tuaj yeem qhia tias muaj teeb meem tsaus. Ib qho chaw xws li qhov teeb meem tsaus ntuj tau kwv yees raws li cov khoom ntawm kev puas tsuaj ntawm cov teeb meem tsaus ntuj yog qhov chaw ntawm peb lub tsev galaxy Milky Way.
Kev tshawb pom cov teeb meem tsaus nti hauv nruab nrab ntawm peb lub tsev galaxy Milky Way
Muaj qhov qhia tau tias muaj qhov sib txawv ntawm lub qhov cub microwave hauv nruab nrab ntawm qhov nruab nrab ntawm Milky Way (MW). Qhov ci ntsa iab tshaj plaws tau thov kom yog vim synchrotron emission los ntawm relativistic electrons thiab positrons generated nyob rau hauv WIMP tsaus teeb meem puas tsuaj, li no ib tug ncua diffuse γ-duab tshav teeb liab nyob rau hauv lub zog ntau txog li ob peb puas GeV tau kwv yees. Tom qab ntawd, Fermi-Large Area Telescope (LAT) tau kuaj pom γ-ray teeb liab uas tau txheeb xyuas tias Galactic Center Excess (GCE). Tsis ntev, nws tau pom tias Galactic Center Excess (GCE) kuj tuaj yeem yog vim cov hnub qub neutron qub (millisecond pulsars). Nws tau xav tias morphology ntawm GCE yuav yog ib qho tseem ceeb - ib tug symmetrical kheej kheej-shaped GCE yuav qhia tau hais tias ntawm γ-ray emission los ntawm kev puas tsuaj ntawm cov teeb meem tsaus nti (DM) hais thaum ib tug flattened morphology ntawm GCE yuav qhia tau hais tias ntawm γ-ray emission los ntawm millisecond pulsars (MSP).
Kev soj ntsuam dav dav ntawm Milky Way galactic center los ntawm Fermi-Large Area Telescope (LAT) tau nthuav tawm ib qho chaw tiaj tus asphericity. Ordinarily, ib tug yuav koom nrog cov kev soj ntsuam asphericity rau cov hnub qub qub (MSP) txawm li cas los xij txoj kev tshawb fawb tsis ntev los no tau tshaj tawm rau 16 Lub Kaum Hli 2025 tau xaus lus tias GCE morphologies tau kwv yees los ntawm ob lub hnub qub qub (MSP) thiab cov teeb meem tsaus ntuj (DM) cov qauv kev puas tsuaj yog qhov sib txawv.
Txhawm rau kawm txog kev faib cov teeb meem tsaus ntuj, cov kws tshawb fawb tau sim simulation ntawm morphology ntawm MW (Milky Way) zoo li galaxies. Lawv pom tias cov teeb meem tsaus ntuj halos nyob ib ncig ntawm lub galaxies thiab nyob ib ncig ntawm lub hauv paus cheeb tsam ntawm lub galaxies tsis tshua muaj spherical li assumed nyob rau hauv anisotropic qauv. Hloov chaw, qhov kev tshuaj ntsuam tau pom qhov ua kom pom qhov tsaus nti qhov ntom ntom rau txhua lub galaxies. Qhov no tsis yog-axisymmetric tsaus teeb meem (DM) kev faib tawm kuj tau pom los ntawm kev sib koom ua ke ntawm Milky Way galaxy hauv thawj peb txhiab xyoo hauv keeb kwm ntawm ntug. Kev soj ntsuam morphology ntawm GCE yog flattened nyob rau hauv nruab nrab cheeb tsam, uas yog feem ntau xav tias yog yam ntxwv ntawm qub hnub qub (MSP) tis. Txoj kev tshawb fawb tshiab tau pom tias cov teeb meem tsaus ntuj (DM) tsim kom muaj cov khoom sib xws hauv lub thawv. Yog li, ob qho tib si tsaus nti (DM) kev puas tsuaj thiab millisecond pulsars (MSPs) kev xav rau GCE tau pom zoo sib npaug.
Txawm hais tias pom GCE yog vim muaj teeb meem tsaus ntuj (DM) lossis vim yog millisecond pulsars (MSPs) yuav paub thaum γ-ray observatories zoo li Cherenkov Telescope Array Observatory (CTAO) thiab Southern Wide-field Gamma-ray Observatory (SWGO) ua tiav lawv cov kev tshawb fawb tera-gamma ray yav tom ntej. Cov gamma rays uas tsim los ua ib qho kev puas tsuaj ntawm cov teeb meem tsaus ntuj (DM) hauv qhov chaw galactic yuav yog ultra-high-zog photons nrog lub zog siab heev ntawm kwv yees li 0.1 tera-electron-volts (TeV). Tus qauv gamma-ray telescopes tsis tuaj yeem ntes cov duab hluav taws xob siab ncaj qha. Tera-gamma rays yuav yog lub hom phiaj tseem ceeb rau yav tom ntej γ-ray observatories xws li CTAO thiab SWGO.
Txoj kev tshawb no yog ib kauj ruam tom ntej hauv kev tshawb pom cov teeb meem tsaus ntuj hauv qhov chaw los ntawm nws cov khoom rhuav tshem txawm li cas los xij muaj cov teeb meem tsaus ntuj ntawm qhov chaw galactic yuav xav tau kev pom zoo los ntawm ultra-siab zog γ-ray observatories xws li CTAO lossis SWGO yav tom ntej. Ntau qhov kev nce qib tseem ceeb hauv kev tshawb fawb ntawm cov teeb meem tsaus ntuj yuav yog kev tshawb pom ncaj qha ntawm ib qho DM particle.
***
References:
- Hochberg, Y., Kahn, YF, Leane, RK et al. Cov txheej txheem tshiab rau kev tshawb nrhiav qhov tsaus ntuj. Nat Rev Phys 4, 637–641 (2022). https://doi.org/10.1038/s42254-022-00509-4
- Misiaszeka M. thiab Rossib N. 2024. Direct detection of dark matter: a critical review. Symmetry 2024, 16(2), 201; DOI: https://doi.org/10.3390/sym16020201
- Instituto de Física Corpuscular. Hauv kev tshawb nrhiav qhov tsaus ntuj: ib txoj hauv kev tshiab los kuaj pom qhov tsis pom. 22 Lub Yim Hli 2025. Muaj nyob ntawm https://webific.ific.uv.es/web/en/content/search-dark-matter-new-approach-detecting-invisible
- Muru MM, thiab al 2025. Fermi-LAT Galactic Center Tshaj Morphology ntawm Tsaus Matter hauv Simulations ntawm Milky Way Galaxy. Cov ntawv txheeb xyuas lub cev. 135, 161005. Published 16 October 2025. DOI: https://doi.org/10.1103/g9qz-h8wd . Preprint version ntawm arXiv. xa tawm 8 Lub Yim Hli 2025. DOI: https://doi.org/10.48550/arXiv.2508.06314
- Johns Hopkins University. Xov Xwm - Tsis paub meej glow nyob rau hauv txoj kev milky tuaj yeem ua pov thawj ntawm qhov tsaus ntuj. Tshaj tawm rau 16 Lub Kaum Hli 2025. Muaj nyob ntawm https://hub.jhu.edu/2025/10/16/mysterious-glow-in-milky-way-dark-matter/
- Leibniz lub koom haum rau Astrophysics. Xov Xwm - Milky Way qhia txog gamma ray dhau vim muaj teeb meem tsaus nti. Tshaj tawm 17 Lub Kaum Hli 2025. Muaj nyob ntawm https://www.aip.de/en/news/milkyway-gammaray-darkmatter-annihilation/
- Fermi Gamma-ray Space Telescope. Muaj nyob ntawm https://science.nasa.gov/mission/fermi/
- Cherenkov Telescope Array Observatory (CTAO). Muaj nyob ntawm https://www.ctao.org/emission-to-discovery/science/
- Southern Wide-field Gamma-ray Observatory (SWGO). Muaj nyob ntawm https://www.swgo.org/SWGOWiki/doku.php?id=swgo_rel_pub
- Tartu Observatory. Tsaus sab ntawm lub ntiaj teb. Muaj nyob ntawm https://kosmos.ut.ee/en/dark-side-of-the-universe
***
, 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}