ChinaFocus:China'sFASTtelescopediscoversdistantgas-richgalaxies_GuangmingOnlineBEIJING,May10(Xinhua)--Chinesescientistshavediscoveredanabundanceofgas-richgalaxiesinthedistantuniverse,usingtheFive-hundred-meterApertureSphericalradioTelescope(FAST)insouthwestChina'sGuizhouProvince.TheresearchresulthasbeenpublishedonlineinTheAstrophysicalJournalLettersonFriday.Accordingtothestudy,thenewlydiscoveredgalaxies,whoseradiowaveemissionshavetakenalmosttheageofthesolarsystemtoreachtheearth,containsimilarormoreatomichydrogengasthanthetensofthousandsofgalaxiespreviouslysurveyedwithotherradiotelescopes.XiHongweifromtheNationalAstronomicalObservatoriesundertheChineseAcademyofSciences(NAOC),theleadauthor,togetherwithhiscolleaguesfromAustralia,theUnitedStatesandRussia,revealedthepropertiesofsixnewhigh-redshiftgalaxiesinthestudy.Thenewhigh-redshiftgalaxysampleprovidestheopportunitytobetterinvestigatetheevolutionofcoolgasingalaxies,saidthepaper."Alargersamplesizeinthefuturewillallowustorefineourknowledgeoftheformationandevolutionofgalaxies."Hydrogenisthemostcommonelementintheuniverse.Initsneutralform,itisabundantinspiralgalaxiessuchastheMilkyWay.Neutralhydrogenistheprimarycomponentofthecoolinterstellarmedium(ISM)andisthereservoiroffuelforstarformation.However,owingtothesensitivityofexistingradiotelescopes,theunderstandingoftheevolutionoftheISMingalaxiesremainslimited."Wehavecarriedoutablindneutralhydrogensearch,ortheFASTUltra-DeepSurvey.Thesediscoveriesarepartoftheongoingsurvey,showingthetremendoussensitivityoftheworld'slargestradiotelescope,"saidPengBo,ascientistattheNAOC."ThenewFASTsurveyhassofardiscoveredover100newgalaxiesatdistancesofupto5billionlightyears,withthefinalnumberexpectedtoreachover1,000,"Pengadded.Theresearchersconcludedthatgalaxies4billionyearsagohadmuchmorestar-forminggasthancurrent-daygalaxies,andthatdistantgalaxieshavemuchgreatergasreservoirsthanpreviouslybelieved.Meanwhile,becausethenewlydiscoveredgalaxiesareveryfaintatsuchlargedistancesandhavedifferentwavelengths,FASTwasnotabletolocatetheopticalcounterpartswiththesameaccuracyasopticaltelescopes.WiththehelpofexpertsusingthelargestopticaltelescopesintheUnitedStatesandRussia,thecounterpartgalaxieswereeventuallyidentified.Itwasfoundthatthesecounterpartscontain2-3timesasmanystarsastheMilkyWay,butcontain10timesthemassofhydrogengas,Pengsaid."ThissuccessfulcollaborativeprogrambetweenChineseandAustralianradioastronomersdemonstratesthetremendouspotentialofthenewgenerationofradiotelescopes,"saidListerStaveley-Smith,aprofessorfromtheUniversityofWesternAustralia.FASTistheworld'slargestsingle-dishradiotelescope,withareceptionareaequalto30standardfootballfields.LocatedinadeepandroundkarstdepressioninGuizhouProvince,FASTstartedformaloperationinJanuary2020andofficiallyopenedtotheworldonMarch31,2021.Editor:DisclaimerTheviewsandopinionsexpressedinthisarticlearethoseoftheauthor's,GMW.cnmakesnorepresentationsastoaccuracy,suitability,orvalidityofanyinformationonthissiteandwillnotbeliableforanyerrors,omissions,ordelaysinthisinformation.