WALƘIYAR RADIYO TARA CIKIN DAƘIƘA 106, SANNAN SHIRU

Fashewar radiyo masu sauri (fast radio bursts) gajerun walƙiyoyin raƙuman radiyo ne, masu ɗaukar ’yan milli-daƙiƙa, da ke isowa gare mu daga wasu galaxy. Har yanzu ana muhawara kan asalinsu, kuma tambaya ɗaya ce ta fi rinjaye: shin dukansu suna maimaitawa? Wasu tushe suna walƙiya akai-akai; yawancinsu an gan su sau ɗaya kawai. A cikin kundi na biyu na na’urar hangen nesa ta radiyo ta Kanada CHIME, wadda ke binciken sararin arewa kowace rana tsakanin megahertz 400 zuwa 800, kusan kashi 2.4% ne kawai na tushe 3,641 ke maimaitawa.

Nazarin dukan rukunoni yawanci suna ɗauka cewa kowane tushe mai maimaitawa yana harbawa a matsakaicin gudu tsayayye. Ryan Mckinven, na Jami’ar McGill, da kusan abokan aiki talatin na haɗin gwiwar CHIME/FRB yanzu sun bayyana wani tushe da ke karya wannan zato fiye da kowane.

Mintuna biyu na hargitsi

A ranar 1 ga Yuni 2021, CHIME ta naɗi fashewa tara cikin daƙiƙa 106.5 daga wani tushe da ake kira yanzu FRB 20210601A. Wata matsalar hanyar sadarwa a lokacin ta dakatar da faɗakarwar atomatik, don haka babu wanda ya lura. An gano fashewar ne kawai a Disamba 2024, a lokacin wani bincike na tsari a kan ma’ajiyar bayanai don kundi na biyu.

Sai ƙungiyar ta nemi ƙari. CHIME ba ta motsi: yayin da Duniya ke juyawa, wannan ɓangaren sararin sama yana ratsa filin ganinta sau ɗaya a rana, na kusan mintuna goma. Tsakanin Yuli 2018 da ƙarshen 2025, hakan ya kai kusan awanni 320 na lura: kusan 132 kafin guguwar, 188 bayanta. Ba ko fashewa ɗaya ƙari, ko da masu rauni da ke ƙasa da iyakar ganowa kaɗan a kwanakin da ke kewaye da guguwar. Ya zuwa ƙarshen 2025, shirun bayan tagar aiki ya ɗauki aƙalla kwanaki 1,674.

A cikin waɗannan daƙiƙa 106.5, fashewar sun iso ba bisa tsari ba, kamar ɗigon ruwan sama, a kusan 0.075 a kowane daƙiƙa. A wannan gudun, yiwuwar ƙarin daƙiƙa 40 ba tare da fashewa ba tana faɗuwa ƙasa da kashi 5%. Duk da haka, lokacin da tushen ya ratsa tsakiyar filin ganin CHIME bayan ’yan mintuna, babu abin da ya zo: wani abu ya kashe.

Rabin guguwar ne kawai aka gani

Duk fashewar tara sun iso ne lokacin da tushen yake a cikin reshen gefe (side lobe) na ɗamarar karɓar siginar CHIME (beams) — gefen filin ganinta mara hankali sosai, kusan kashi ɗaya cikin huɗu na hankalin tsakiya. Da guguwar ta zo ’yan mintuna daga baya, lokacin da tushen ke wucewa sama kai tsaye, ƙungiyar ta ƙiyasta CHIME za ta naɗi aƙalla fashewa 21, wataƙila kusan 70.

Yaya girman wannan? Ƙungiyar ta kwatanta shi da biyu daga cikin tushe masu maimaitawa mafiya yawan fashewa da aka sani, waɗanda babbar na’urar hangen nesa ta radiyo ta China FAST ke bibiya. Da cikakken hankalin FAST, sun kai fashewa 46 da 23 a cikin tagar daƙiƙa 106.5. Amma idan aka riƙe fashewar da ke da haske kamar mafi raunin cikin taran kawai, mafi kyawun tagoginsu suna ɗauke da 6 da 8 kawai. A cewar marubutan, FRB 20210601A tana nuna mafi girman yawan fashewa a cikin mintuna da aka taɓa ruwaito daga tushe mai maimaitawa a hankali mai kama da juna — ko da yake kwatancen ba daidai ba ne sosai, tun da na’urorin biyu suna saurare a mitoci daban-daban da kuma kiɗa daban-daban.

Tushe na yau da kullum mai jadawali na ban mamaki

In ban da haka, tushen yana kama da na yau da kullum. Fashewar suna da dogayen siffofi masu sassa da yawa da aka saba gani a masu maimaitawa, kuma yadda iskar gas da suke ratsawa ke bazawa da murɗa siginarsu yana kusa da matsakaicin na masu maimaitawa na CHIME. Ba a iya tantance galaxy mai masaukinsu ba, kuma binciken abokan hulɗa na hasken gamma, X-ray, haske na gani ko radiyo mai dorewa bai sami komai ba.

Makamashin da aka saki ƙanƙane ne: kusan kashi ɗaya cikin miliyan na makamashin maganaɗisu da aka adana a cikin magnetar na yau da kullum, wato tauraron neutron mai ƙarfin maganaɗisu sosai, ko da an ɗauki nisan tushen a mafi girman abin da bayanan suka bari.

Me zai iya kunnawa da kashewa haka?

Marubutan sun auna ra’ayoyi da dama, ba tare da wanda ya yi nasara ba:

• Pulsar masu tsayawa-tsayawa (intermittent pulsars), waɗanda ke kashewa na dogon lokaci. Ɗaya da aka samu kwanan nan a cikin Galaxy ɗinmu, PSR J2109+50, ta nuna yanayinta mai haske sau ɗaya kawai a cikin wata ɗaya, na kusan daƙiƙa 90 — amma hasken ta ya yi ƙasa sosai.
• Fashewar magnetar. A cikin Galaxy ɗinmu, magnetar 1E 2259+586 ta harba fashewar X-ray sama da 80 cikin awanni huɗu bayan shekaru 5.6 na natsuwa. Duk da haka, guguwar mintuna biyu ta fi matsewa nesa ba kusa ba fiye da kowane misali da aka sani a Galaxy ɗinmu.
• Tauraro abokin tafiya, wanda iskarsa ko kewayarsa za ta buɗe ɗan gajeren taga na fitarwa ko ganuwa.
• Lanƙwasa haske (lensing), inda wani dunƙulen abu ke ƙara girman tushe da yawanci ya yi rauni sosai na ɗan lokaci.

Rukunin da ke ɓoye

Idan irin waɗannan tushe masu zuwa lokaci-lokaci suna wanzuwa, CHIME ce mafi kyawun wurin samo su, saboda binciken da take yi kowace rana na sararin sama mai faɗi. Wani samfurin ƙididdiga mai sauƙi yana nuna kusan 9 daga cikinsu a iya kaiwar CHIME — da babban rashin tabbas, daga 1 zuwa sama da 200 — kuma yana hasashen, a mafi kyawun hali, ƙarin gano ɗaya zuwa huɗu a cikin shekaru goma masu zuwa. Wasu fashewar da suke kama da ta sau ɗaya kawai na iya ma zama guguwa da aka kama sashinsu kawai. Na’urar hangen nesa mai hankali kamar FAST, da aka nufa ga tushen a cikin shekarunsa na shiru, za ta iya gwada ra’ayin ta hanyar kama fashewa masu rauni.