TAURARI MAFI ƘARFI NA RADIO DA AKA TAƁA GANO

Wasu tarin taurari suna da zuciya mai matuƙar aiki: abubuwan da ke faɗawa cikin wani babban ramin baƙi (supermassive black hole) suna ba da ƙarfi ga jets masu saurin kusa da na haske (relativistic jets) waɗanda ke haske sosai a cikin raƙuman radio. Waɗannan radio galaxies su ne mafi tsananin nau’in wannan aiki. Jets ɗinsu na iya tsara yadda tarin taurarin da ke ɗauke da su ke samar da taurari, kuma a sararin samaniya mai nisa suna aiki kamar fitilun da ke nuna manyan tarin taurari da ƙananan gungu (clusters).

Ba su da yawa kuma suna ɓoye

Shaidu da ke ƙaruwa suna nuna cewa yawancin waɗannan cibiyoyi masu aiki a farkon sararin samaniya suna ɓoye a bayan iskar gas mai ƙura. Jet na radio ne kaɗai ke huda shi. Sai su yi kama da radio galaxies maimakon quasars masu haske. Wani bincike na 2024 ya ƙiyasta cewa har kashi 90% daga cikinsu na iya kasancewa a rufe bayan redshift 3.5.

Duk da haka kaɗan ne kawai aka sani. Wani bita na 2008 ya lissafa radio galaxies 37 bayan redshift 3, kuma biyu kawai bayan 4.5; an tabbatar da ƙarin huɗu tun daga lokacin. Yawancinsu an same su ne da ma’aunin radio ɗaya — bakan (spectrum) “mai tsananin gangara” (ultra-steep) — wanda zai iya rasa da yawa daga cikinsu.

Hanyar farauta

Barbara Balmaverde da abokan aikinta, a Cibiyar Ilimin Taurari ta Ƙasar Italiya (INAF) a Turin, sun yi amfani da wata hanya: Lyman break. Tarin taurari a redshift kusan 5 yana ɓacewa a wasu launukan gani saboda hydrogen da ke kan hanya yana shanye haskensa. Sun haɗa tushen radio daga binciken TGSS (Giant Metrewave Radio Telescope, MHz 150) da zurfafan hotunan gani na na’urar hangen nesa ta Subaru, sannan da madaidaitan wurare daga VLA.

A ranar 18 ga Satumba 2025, sun nuna Very Large Telescope ta ESO a Chile zuwa wani ɗan takara, tushen radio TXS 2354+015.

Tushen a launuka biyar daga na’urar hangen nesa ta Subaru: yana ɓacewa a cikin maɗaukai biyu mafi shuɗi, alamar tarin taurari kusa da redshift 5. — Hoto na 1, Balmaverde et al. (2026), arXiv:2609.28632.

Abin da suka gano

Bakan yana nuna layi mai haske, mara daidaito sosai: fitar Lyman-alpha ta hydrogen. Layi na biyu, mafi suma, daga nitrogen yana tabbatar da shi. Redshift ɗin shi ne z = 4.946 ± 0.001. Wannan ya sa TXS 2354+015 ya zama radio galaxy na biyu mafi nisa da aka sani, bayan TN J0924-2201 a z = 5.19.

Bakan radio ɗinsa, da aka auna daga MHz 74 zuwa GHz 4.8, yana bin dokar ƙarfi (power law) ɗaya ba tare da karyewa ba. A mitar MHz 500 a tsarinsa na hutu (rest frame), ƙarfinsa ya kai watt 6.2 × 10²⁹ a kowane hertz. Wanda ya riƙe tarihin a baya, TN J0924-2201, ya kai 3.2 × 10²⁹. Don haka TXS 2354+015, a cewar masu binciken, shi ne radio galaxy mafi ƙarfi da aka sani a yanzu — kusan ninki biyu na tsohon zakara.

Bakan radio na TXS 2354+015 daga MHz 74 zuwa GHz 4.8: dokar ƙarfi ɗaya madaidaiciya. — Hoto na 4, Balmaverde et al. (2026), arXiv:2609.28632.

Hydrogen mai haske da ke kewaye da shi ya miƙe kusan kiloparsec 6, wataƙila fiye, tun da tsagar na’urar hangen nesa ta kusan yin kusurwar digiri 90 da jets na radio.

Darasi ga farauta

Bakan radio ɗinsa ba mai tsananin gangara ba ne. Tare da abubuwan da aka gano a baya, wannan yana nuna cewa ma’aunin radio na gargajiya yana bayyana wani ɓangare ne kawai na waɗannan tarin taurari. Hanyar Lyman break tana gano wasu.

Abin da har yanzu ba a tabbatar ba

Nauyin tarin taurarin da ke ɗauke da shi ƙiyasi ne kawai — kusan nauyin Rana 2 × 10¹², wataƙila ƙasa da haka sau goma — kuma masu binciken sun jaddada cewa ana buƙatar ingantattun bayanai. Kuma wannan abu ɗaya ne: gina samfuri na gaske na radio galaxies a kusa da redshift 5 shi ne mataki na gaba.