Ke aʻo ʻana o ke ao holoʻokoʻa: REACH hoʻokolohua e ʻike i ka laina 21-cm paʻakikī mai Cosmic Hydrogen 

Nānā o 26 knm Radio nā hōʻailona, ​​i hana ʻia ma muli o ka hoʻololi hyperfine o ka hydrogen cosmic hāʻawi i kahi mea hana ʻē aʻe i ke aʻo ʻana o ka wā mua ke ao holoʻokoʻa. No ka wā kūʻokoʻa o ke keiki pēpē ke ao holoʻokoʻa i ka wā ʻaʻole i hoʻokuʻu ʻia ke kukui, he puka aniani wale nō paha nā laina 26 cm. Eia naʻe, ua hoʻololi ʻia kēia mau ʻulaʻula Radio nā hōʻailona i hoʻopuka ʻia e ka cosmic hydrogen i ka wā mua ke ao holoʻokoʻa nawaliwali loa a paʻa ʻole i kēia manawa. I ka makahiki 2018, ua hōʻike ka hoʻokolohua EDGE i ka ʻike ʻana i nā hōʻailona 26 cm akā ʻaʻole hiki ke hōʻoia kūʻokoʻa nā ʻike. ʻO ka pilikia nui, ʻo ia ka ʻōnaehana a me ka hoʻohaumia ʻana me nā hōʻailona ʻē aʻe mai ka lani. ʻO ka REACH Experiment ka hoʻohana ʻana i nā ʻano hana kūʻokoʻa e lanakila ai i ka bottleneck. Manaʻo ʻia e hiki i kēia hui noiʻi ke ʻike pono i kēia mau hōʻailona paʻakikī i ka wā e hiki mai ana. Inā kūleʻa, hiki i ka REACH Experiment ke lawe mai i ka '26 cm radio astronomy' i mua o ke aʻo ʻana o ka ke ao holoʻokoʻa a kōkua nui iā mākou i ka wehe ʻana i nā mea pohihihi o ka wā mua ke ao holoʻokoʻa. 

I ka wā e pili ana i ke aʻo ʻana o mua honua, inoa i hoʻokuʻu ʻia ʻO James Webb Space Telescope (JWST) e puka mai ana ma ko kakou noonoo. JWST, he hope o ka lanakila nui ʻO Hubble telescope, he makahiki-based, infrared observatory i hoʻolako ʻia e hopu i nā hōʻailona optical/infrared mai nā hōkū mua a me nā galaxes i hoʻokumu ʻia i ka Kekahi ma hope koke iho o ka Big Bang¹. Eia naʻe, JWST loaʻa i kekahi mau palena a hiki i ka ʻohi ʻana i nā hōʻailona mai ka wā kū ʻole o mua honua he mea hopohopo.  

Papa: Epochs in the history of ke ao holoʻokoʻa mai ka Big Bang  

(Source: Philosophy of Cosmology – 21 cm hope. Loaʻa ma http://philosophy-of-cosmology.ox.ac.uk/images/21-cm-background.jpg)  

A hiki i ka 380 k makahiki ma hope o ka big bang, ka ke ao holoʻokoʻa ua hoʻopiha ʻia me ke kinoea ionised a ua opaque loa. Ma waena o 380k - 400 miliona mau makahiki, ka ke ao holoʻokoʻa ua lilo i kū ʻole a maopopo. Hoʻomaka ka manawa o ka reionisation ma hope o kēia kaʻina e hoʻomaka ana i ka 400 miliona ma hope o ka pā nui.  

I ka wā kū ʻole o ka wā mua ke ao holoʻokoʻa, i ka wa ke ao holoʻokoʻa ua hoʻopiha ʻia me nā kinoea kū ʻole a ʻaʻole maopopo, ʻaʻohe hōʻailona optical i hoʻokuʻu ʻia (no laila ua kapa ʻia ʻo ka makahiki ʻeleʻele). ʻAʻole hoʻokuʻu ʻia nā mea i hui pū ʻia. He paʻakikī kēia i ke aʻo ʻana i ka wā mua Kekahi o ka wā kū ʻole. Eia nō naʻe, ʻo ka radiation microwave o 21 cm ka lōʻihi o ka nalu (e like me 1420 MHz) i hoʻokuʻu ʻia e ke anuanu cosmic hydrogen i kēia wā ma muli o ka hoʻololi hyperfine (mai ka milo like a hiki i ka spin anti-parallel paʻa) hāʻawi i nā manawa i nā mea noiʻi. E hoʻololi ʻia kēia radiation microwave 21 cm i ka hiki ʻana i ka Honua a e nānā ʻia ma 200MHz a 10 MHz mau alapine e like me nā hawewe lekiō.^2,3.  

21 knm radio astronomy: ʻO ka nānā ʻana i nā hōʻailona hydrogen cosmic 21-centimeter e hāʻawi i kahi ala ʻē aʻe i ke aʻo ʻana o ka mua ke ao holoʻokoʻa ʻoi aku ka nui o ka wā kūʻokoʻa i nele i ka puka māmā. Hiki i kēia ke hoʻomaopopo iā mākou e pili ana i ka physics hou e like me ka hoʻohele ʻana o ka mea i ka manawa, ka ikehu ʻeleʻele, ka mea ʻeleʻele, ka nui neutrino, a me ka hoʻonui.².  

Eia naʻe, ʻo nā hōʻailona 21-cm i hoʻokuʻu ʻia e ka cosmic hydrogen i ka wā mua ke ao holoʻokoʻa paʻakikī ka pae. Ua manaʻo ʻia he nāwaliwali loa (ma kahi o hoʻokahi haneli kaukani ka nāwaliwali ma mua o nā lekiō ʻē aʻe e puka mai ana mai ka lewa mai). ʻO ka hopena, aia kēia ala i ka wā kamaliʻi.  

I ka makahiki 2018, ua hōʻike ka poʻe noiʻi i ka ʻike ʻana i kēlā hōʻailona lekiō ma ke alapine o 78 MHz nona ka ʻike i kūlike me nā manaʻo no ka hōʻailona 21-centimeter i hoʻopuka ʻia e ka primordial cosmic hydrogen.⁴. Akā ʻaʻole hiki ke hoʻopaʻa kūʻokoʻa ʻia kēia ʻike ʻana o ka lekiō 21-cm primordial no laila ʻaʻole hiki ke hoʻokumu ʻia ka hilinaʻi o ka hoʻokolohua a hiki i kēia manawa. ʻO ka pilikia nui e like me ka haumia me nā hōʻailona radio foreground.  

ʻO ka milestone hou loa ka hōʻike o Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) ma 21 Iulai 2022. E hoʻohana ʻo REACH i kahi ala hoʻokolohua hou e ʻike ai i kēia mau hōʻailona lekiō kosmic nāwaliwali loa e hāʻawi i kahi manaʻolana hou no ka hōʻoia ʻana i nā hōʻailona cosmic 21-centimeter.  

ʻO ka Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) he hoʻokolohua 21-cm awelika. Makemake kēia e hoʻomaikaʻi i ka nānā ʻana ma o ka hoʻokele ʻana i nā pilikia i kū ʻia e nā mea kani e pili ana i nā hōʻailona ʻōnaehana koena i ka ʻikepili. Hoʻopili ia i ka ʻike ʻana a me ka wehewehe pū ʻana i nā systematics me nā foregrounds a me ka hōʻailona cosmological me ka hoʻohana ʻana i nā helu Bayesian. ʻO ka hoʻokolohua pili i ka nānā like ʻana me ʻelua antenna ʻokoʻa, kahi ʻōnaehana ultra-wideband (redshift range ma kahi o 7.5 a 28) a me kahi calibrator hoʻokipa e pili ana i nā ana i loko o ke kahua.  

He mea koʻikoʻi kēia hoʻomohala ʻana i kona hiki ke lilo i kekahi o nā mea hana maikaʻi loa (a ʻoi aku ka maikaʻi o ke kumukūʻai vis-a-vis makahiki-based observatories like James webb) no ke aʻo mua ʻana ke ao holoʻokoʻa a me ka hiki ke hoʻokomo i nā physics kumu hou.  

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E hoʻomaopopo ':  

1. Prasad U., 2021. ʻO James Webb Space Telescope (JWST): ʻO ka Observatory Space mua i hoʻolaʻa ʻia i ke aʻo ʻana o ke ao holoʻokoʻa. ʻElepa ʻepekema. Hoʻopuka ʻia 6 Nowemapa 2021. Loaʻa ma 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 a me Loeb A., 2012. 21 knm cosmology i ka 21st century. Nā hōʻike e pili ana i ka holomua ma ke kino 75 086901. Loaʻa ma https://iopscience.iop.org/article/10.1088/0034-4885/75/8/086901. Loaʻa ka paʻi mua ma arXiv ma https://arxiv.org/abs/1109.6012  pdf version  https://arxiv.org/pdf/1109.6012.pdf 

3. Kulanui ʻO Oxford. Philosophy of Cosmology - 21 cm hope. Loaʻa ma http://philosophy-of-cosmology.ox.ac.uk/21cm-background.html 

4. Bowman, J., Rogers, A., Monsalve, R. et al. Hoʻopili ʻia kahi ʻaoʻao absorption ma 78 megahertz i ka kikoʻī o ka lani-averaged spectrum. Nature 555, 67–70 (2018). https://doi.org/10.1038/nature25792 

5. de Lera Acedo, E., de Villiers, DIL, Razavi-Ghods, N. et al. ʻO ka radiometer REACH no ka ʻike ʻana i ka hōʻailona hydrogen 21-cm mai ka redshift z ≈ 7.5–28. Nat Astron (2022). https://doi.org/10.1038/s41550-022-01709-9  

6. Eloy de Lera Acedo 2022. Ka wehe ʻana i nā mea pohihihi o ke Universe pēpē me ka radiometer REACH. Loaʻa ma ka pūnaewele ma  https://astronomycommunity.nature.com/posts/u 

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