Nazarin Farkon Universe: Gwajin REACH don gano layin 21-cm mai wahala daga Cosmic Hydrogen 

Lura da siginar rediyo mai tsawon santimita 26 , wadda aka samar sakamakon canjin haemoglobin mai girman gaske, tana ba da wata hanya ta daban ga nazarin sararin samaniya na farko . Dangane da zamanin da ba a fitar da haske ba, layukan santimita 26 wataƙila taga ce kawai. Duk da haka, waɗannan siginar rediyo masu canzawa da hydrogen na sararin samaniya ke fitarwa a sararin samaniya na farko suna da rauni sosai kuma sun kasance masu wuyar fahimta har yanzu. A cikin 2018, gwajin EDGE ya ba da rahoton gano siginar santimita 26 amma ba za a iya tabbatar da sakamakon da kansa ba. Babban matsalar ita ce tsarin kayan aiki da gurɓata sauran siginar daga sama. Gwajin REACH shine amfani da wata hanya ta musamman don shawo kan matsalar. Ana fatan wannan ƙungiyar bincike za ta iya gano waɗannan siginar da ba ta da tabbas nan gaba kaɗan. Idan ta yi nasara, Gwajin REACH na iya kawo 'tauraron rediyo mai tsawon santimita 26' a gaba a cikin nazarin sararin samaniya na farko kuma ya taimaka mana sosai wajen warware asirin sararin samaniya na farko.

Idan ana maganar nazarin sararin samaniya na farko , sunan na'urar hangen nesa ta sararin samaniya ta James Webb (JWST) da aka ƙaddamar kwanan nan ya bayyana a cikin zuciyarmu. JWST , magajin Hubble mai nasara sosai , wani na'urar hangen nesa ce mai amfani da infrared wadda aka tanadar wa sararin samaniya don ɗaukar siginar gani/infrared daga taurari da taurarin farko da aka samar a cikin sararin samaniya jim kaɗan bayan Big Bang ^1. Duk da haka, JWST tana da wasu ƙuntatawa dangane da ɗaukar sigina daga zamanin tsaka-tsaki na sararin samaniya na farko.

Tebur: Zamanin da aka yi a tarihin duniya tun bayan Big Bang

(Tushe: Falsafar Ilimin Halitta – asalinsa santimita 21. Akwai a http://philosophy-of-cosmology.ox.ac.uk/images/21-cm-background.jpg )

Har zuwa shekaru 380 bayan babban fashewar, sararin samaniya ya cika da iskar gas mai ionized kuma ba ta da cikakken haske. Tsakanin shekaru miliyan 380 zuwa miliyan 400, sararin samaniya ya zama tsaka-tsaki da bayyananne. Zamanin sake fasalin ya fara ne bayan wannan matakin, wanda ya fara daga miliyan 400 bayan babban fashewar.

A lokacin tsaka-tsakin sararin samaniya na farko , lokacin da duniya ta cika da iskar gas mai tsaka-tsaki kuma ta kasance mai haske, babu siginar gani da aka fitar (saboda haka ake kiranta zamanin duhu). Kayan da aka haɗa ba sa fitar da haske. Wannan yana haifar da ƙalubale a nazarin farkon Duniyar tsaka-tsakin yanayi. Duk da haka, hasken microwave na tsawon santimita 21 (wanda ya yi daidai da 1420 MHz) wanda iskar hydrogen mai sanyi da tsaka-tsakin yanayi ke fitarwa a wannan lokacin sakamakon canjin hyperfine (daga juyawa mai layi ɗaya zuwa juyawa mai daidaituwa) yana ba da dama ga masu bincike. Wannan hasken microwave mai santimita 21 za a canza shi da zarar ya isa Duniya kuma za a lura da shi a mita 200MHz zuwa 10 MHz a matsayin raƙuman rediyo ^2,3.

Tauraron taurari na rediyo mai tsawon santimita 21: Lura da siginar hydrogen ta sararin samaniya mai tsawon santimita 21 yana ba da wata hanya ta daban don nazarin sararin samaniya na farko musamman na lokacin da ba shi da wani hayaki mai haske. Wannan kuma zai iya sanar da mu game da sabbin kimiyyar lissafi kamar rarrabawar abu a kan lokaci, makamashin duhu, ma'aunin duhu, taro na neutrino, da hauhawar farashin ^kaya.

Duk da haka, siginar 21-cm da iskar hydrogen ta sararin samaniya ke fitarwa a farkon matakin sararin samaniya ba ta da tabbas. Ana sa ran za ta yi rauni sosai (kimanin sau dubu ɗari fiye da sauran siginar rediyo da ke fitowa daga sama). Sakamakon haka, wannan hanyar har yanzu tana cikin ƙuruciya.

A shekarar 2018, masu bincike sun bayar da rahoton gano irin wannan siginar rediyo a mitar 78 MHz wanda bayanin martabarsa ya yi daidai da tsammanin siginar santimita 21 da sinadarin hydrogen ⁴ na sararin samaniya ke fitarwa . Amma ba za a iya tabbatar da wannan gano siginar rediyo ta santimita 21 ba, don haka ba za a iya tabbatar da ingancin gwajin zuwa yanzu ba. Babban matsalar da alama ta shafi gurɓatar siginar rediyo ta gaba.

Sabon ci gaba shine rahoton Gwajin Rediyo don Binciken Cosmic Hydrogen (REACH) a ranar 21 ga Yuli 2022. REACH zai yi amfani da sabon tsarin gwaji don gano waɗannan siginonin rediyo na sararin samaniya masu rauni don haka suna ba da sabon bege don tabbatar da siginar sararin samaniya na santimita 21.  

Gwajin Rediyo don Binciken Haskar Hydrogen ta Duniya (REACH) gwaji ne mai girman 21-cm wanda aka yi a sararin samaniya. Wannan yana da nufin inganta lura ta hanyar sarrafa matsalolin da kayan aiki ke fuskanta dangane da siginar tsarin da ke cikin bayanan. Yana mai da hankali kan ganowa da kuma yin bayani game da tsarin tare da gaba da siginar sararin samaniya ta amfani da ƙididdigar Bayesian. Gwajin ya ƙunshi lura a lokaci guda tare da eriya biyu daban-daban, tsarin ultra-wideband (zagayen redshift kusan 7.5 zuwa 28) da kuma calibrator mai karɓa bisa ga ma'aunin cikin filin.

Wannan ci gaban yana da matuƙar muhimmanci ganin cewa yana da yuwuwar zama ɗaya daga cikin mafi kyawun kayan aiki (kuma mai inganci sosai idan aka kwatanta da wuraren lura na sararin samaniya kamar James Webb ) don nazarin sararin samaniya na farko da kuma yiwuwar amfani da sabbin kimiyyar lissafi.

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References:  

1. Prasad U., 2021.James Webb Space Telescope (JWST): Cibiyar Kula da Sararin Samaniya ta Farko da aka sadaukar don Nazarin Farkon sararin samaniya. Kimiyyar Turai. An buga 6 Nuwamba 2021. Akwai a http://scientificeuropean.co.uk/sciences/space/james-webb-space-telescope-jwst-the-first-space-observatory-dedicated-to-the-study-of-early-universe/

2. Pritchard JA da Loeb A., 2012. 21 cm cosmology a cikin karni na 21st. Rahoton Ci gaba a Ilimin Kimiyya 75 086901. Akwai a https://iopscience.iop.org/article/10.1088/0034-4885/75/8/086901. Preprint a arXiv akwai a https://arxiv.org/abs/1109.6012  sigar pdf  https://arxiv.org/pdf/1109.6012.pdf 

3. Jami'ar Oxford. Falsafa na Cosmology - 21 cm baya. Akwai a http://philosophy-of-cosmology.ox.ac.uk/21cm-background.html 

4. Bowman, J., Rogers, A., Monsalve, R. et al. Bayanan shayarwa a tsakiya a megahertz 78 a cikin madaidaicin bakan sama. Yanayin 555, 67-70 (2018). https://doi.org/10.1038/nature25792 

5. de Lera Acedo, E., de Villiers, DIL, Razavi-Ghods, N. et al. Rediyon REACH don gano siginar hydrogen 21-cm daga redshift z ≈ 7.5-28. Nat Astron (2022). https://doi.org/10.1038/s41550-022-01709-9  

6. Eloy de Lera Acedo 2022. Bayyana abubuwan asirce na sararin samaniya tare da na'urar rediyon REACH. Akwai akan layi a  https://astronomycommunity.nature.com/posts/u 

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