Free Astronomy Magazine May-June 2024 ARABIC VERSION

33 exploding stars known as super- novae. Their work is published in Nature . Coil and her collaborators have been studying massive “star- burst” galaxies that can drive these ultra-fast outflowing winds. Star- burst galaxies have an exceptionally high rate of star formation. When stars die and explode, they expelgas from the star and its surround- ings back into interstellar space. If enough stars explode near eachother at the same time, the force of these explosions can push the gasout of the galaxy itself into outflow- ing winds, which can travel at up to 2,000 kilometers/second. “These galaxies are really interest- ing,” said Coil, who is also chair of the Department of Astronomy and Astrophysics. “Theyoccurwhentwo big galaxies collide. The merger pushesallthegasintoaverysmall region,whichcausesanintenseburst ofstarformation.Massivestarsburn outquicklyandwhentheydie,they expeltheirgasasoutflowingwinds.” Technologicaldevelopmentsallowed ASKAPtoscanlargeportionsofthe skyatveryfaintlimitswhichmade oddradiocircles(ORCs)detectable forthefirsttimein2019.TheORCs wereenormous—hundredsofkilo- parsecs across, where a kiloparsec is equalto3,260lightyears(forrefer- ence,theMilkyWaygalaxyisabout 30 kiloparsecs across). Multipletheorieswereproposedto explain the origin of ORCs, includ- ing planetary nebulae and black hole mergers, but radio data alone couldnotdiscriminatebetweenthe theories.Coilandhercollaborators were intrigued and thought it was possible the radio rings were a de- velopment from the later stages of thestarburstgalaxiestheyhadbeen studying. They began looking into ORC 4 — the first ORC discovered that is observable from the North- ern Hemisphere. Up until then, ORCs had only been observed through their radio emis- sions,withoutanyopticaldata.Coil’s teamusedanintegralfieldspectro- graphattheW.M.KeckObservatory on Maunakea, Hawaii, to look at ORC4,whichrevealedatremendous amountofhighlyluminous,heated, compressed gas — far more than is seen in the average galaxy. Withmorequestionsthananswers, the team got down to detective work.Usingopticalandinfraredim- aging data, they determined the stars inside ORC 4 galaxy were around 6 billion years old. “There wasaburstofstarformationinthis galaxy, but it ended roughly a bil- lion years ago,” stated Coil. CassandraLochhaas,apostdoctoral fellowattheHarvard&Smithsonian CenterforAstrophysics specializing in the theoretical side of galactic windsandaco-authoronthepaper, ran a suite of numerical computer simulationstoreplicatethesizeand properties of the large-scale radio ring, including the large amount of shocked, cool gas in the central galaxy.Hersimulationsshowedout- flowing galactic winds blowing for 200 million years before they shut off. When the wind stopped, a for- ward-moving shock continued to propelhigh-temperaturegasoutof thegalaxyandcreatedaradioring, whileareverseshocksentcoolergas falling back onto the galaxy. The simulationplayedoutover750mil- lion years — within the ballpark of theestimatedone-billion-yearstel- lar age of ORC 4. “To make this work you need a high-mass outflow rate, meaning it’s ejecting a lot of material very quickly. And the surrounding gas justoutsidethegalaxyhastobelow density,otherwisetheshockstalls. These are the two key factors,” statedCoil. “Itturnsoutthegalaxies we’ve been studying have these high-mass outflow rates. They’re rare, but they do exist. I really do thinkthispointstoORCsoriginating fromsomekindofoutflowinggalac- tic winds.” Not only can outflowing winds help astronomers understand ORCs, but ORCs can help astronomers under- stand outflowing winds as well. “ORCs provide a way for us to ‘see’ the winds through radio data and spectroscopy,” said Coil. “This can help us determine how common these extreme outflowing galactic winds are and what the wind life cycle is. They can also help us learn more about galactic evolution: doall massive galaxies go through an ORC phase? Do spiral galaxies turn elliptical when they are no longer forming stars? I think there is a lot we can learn about ORCs and learn fromORCs.”     33 اﻟـــــﺪواﺋﺮ ـــــﺔ ــــــﺔ اﻟﻔﺮد اﻟﺮادﻳﻮ ﻣﺜــــــﻞ ORC1 اﻟﻤﻮﺿــــــــﺤ ﺔ ﻫﻨــــــــﺎ ﻛﺒــــــــ ة ﻤــــــــﺎ ﻜﻔــــــــــــﻲﻻﺣﺘـــــــــــــﻮاء اﻟﻤﺠــــــــــــﺮات ﻓـــــــــــــﻲ ﻣﺮاﻛﺰﻫـــﺎ و ﺼــــﻞ ﻋﺮﺿـــﻬﺎ إﻟــــﻰﻣﺌــــﺎت اﻟﻀﻮﺋ ﺔ اﻵﻻفﻣﻦ اﻟﺴﻨ . - ﻣﺎﻳﻮ ﻳﻮﻧﻴﻮ 2 0 2 4 ـﻧﺸ ﺗﻢ ﺮ ﻋﻤﻠﻬﻢ ﰲ ﻣﺠﻠﺔ ﻧﻴﺘﴩ . ﻛﺎﻧﺖ ﻛﻮﻳﻞ و ﻣﻌﺎوﻧﻮﻫﺎ ﻳﺪرﺳﻮن ﻣﺠﺮات ﺿﺨﻤﺔ ﻣﻦ ﻧﻮع " اﻻﻧﻔﺠﺎر اﻟﻨﺠﻤﻲ " ﻳﻤﻜﻨﻬﺎ دﻓﻊ ﻫﺬه اﻟﺮﻳﺎح ا ﺘﺪﻓﻘﺔ ﺑﴪﻋﺔ ﻓﺎﺋﻘﺔ . ﺗﺘﻤﺘﻊ ا ﺠـﺮات ذات اﻻﻧﻔﺠﺎرات اﻟﻨﺠﻤﻴﺔ ﺑﻤﻌﺪل ﻣﺮﺗﻔـﻊ ﺑﺸـﻜﻞ اﺳـﺘﺜﻨﺎﺋﻲ ﻟﺘﺸـﻜﻞ ا ﻟﻨﺠـﻮم . ﻋﻨـﺪﻣﺎ ﺗﻤـﻮت اﻟﻨﺠﻮم وﺗﻨﻔﺠﺮ ﻓﺈﻧﻬﺎ ﺗﻄﺮد اﻟﻐﺎز ﻣﻦ اﻟـﻨﺠﻢ وا ﻨﺎﻃﻖ ا ﺤﻴﻄﺔ ﺑﻪ إﱃ اﻟﻔﻀﺎء ﺑ اﻟﻨﺠﻮم . إذا اﻧﻔﺠﺮ ﻋﺪد ﻛﺎفٍ ﻣﻦ اﻟﻨﺠﻮم ﺑﺎﻟﻘﺮب ﻣـﻦ ﺑﻌﻀﻬﺎ اﻟﺒﻌﺾ ﰲ ﻧﻔﺲ اﻟﻮﻗﺖ، ﻓﺈن ﻗﻮة ﻫﺬه اﻻﻧﻔﺠﺎرات ﻳﻤﻜﻦ أن ﺗﺪﻓﻊ اﻟﻐﺎز ﺧﺎرج ا ﺠﺮة ﻧﻔﺴﻬﺎ إﱃ اﻟﺮﻳﺎح ا ﺘﺪﻓﻘﺔ، واﻟﺘـﻲ ﻳﻤﻜـﻦ أن ﺗﻨﺘﻘـﻞ ﺑﴪـﻋﺔ ﺗﺼـﻞ إﱃ 2000 ﻛﻴﻠــﻮﻣﱰ ﰲ اﻟﺜﺎﻧﻴﺔ . ﻗﺎل ﻛﻮﻳﻞ، وﻫﻮ أﻳﻀًﺎ رﺋﻴﺲ ﻗﺴﻢ ﻋﻠﻢ اﻟﻔﻠﻚ وا ﻟﻔﻴﺰﻳﺎء اﻟﻔﻠﻜﻴﺔ " : ﻫﺬه ا ﺠﺮات ﻣﺜ ة ﻟﻼﻫﺘﻤﺎم ﺣﻘًﺎ . ﻓﻬﻲ ﺗﺤﺪث ﻋﻨـﺪﻣﺎ ﺗﺼـﻄﺪم ﻣﺠﺮﺗﺎن ﻛﺒ ﺗﺎن ". واﻟﻔﻴﺰﻳـﺎء اﻟﻔﻠﻜﻴـﺔ " : ﻫـﺬه ا ﺠـﺮات ﻣﺜـ ة ﻣ ﺠﺮﺗﺎن ﻛﺒ ﺗﺎن ". ﻳﺪﻓﻊ اﻻﻧﺪﻣﺎج ﻛﻞ اﻟﻐﺎز إﱃ ﻣﻨﻄﻘﺔ ﺻﻐ ة ﺟﺪًا، ﻣﻤﺎ ﻳﺘﺴﺒﺐ ﰲ اﻧﻔﺠـﺎر ﻣﻜﺜ ـﻒ ﻟﺘﺸـﻜﻞ اﻟﻨﺠـﻮم ﺗﺤــﱰق اﻟﻨﺠـﻮم اﻟﻀــﺨﻤﺔ ﺑـ ـ ﴪﻋﺔ وﻋﻨـﺪﻣﺎ ﺗﻤـﻮت ﺗﻄـﺮد ﻏﺎزاﺗﻬ ـﺎ ﻣﺜ ـﻞ اﻟﺮﻳــﺎح ا ﺘﺪﻓ . ﻘــﺔ ﺳـﻤﺤﺖ اﻟﺘﻄﻮرات اﻟﺘﻜﻨﻮﻟﻮﺟﻴـﺔ ﻟ ﺘﻠﺴـﻜﻮب أﺳـﻜﺎب ﺑﻤﺴﺢ أﺟﺰاء ﻛﺒـ ة ﻣـﻦ اﻟﺴـﻤﺎء ﰲ ﺣـﺪود ﺑﺎﻫﺘﺔ ﻟﻠﻐﺎ ﻳﺔ ﻣﻤﺎ ﺟﻌﻞ دواﺋﺮ اﻟﺮادﻳﻮ اﻟﻔﺮدﻳﺔ ( ﻗﺎﺑﻠﺔ ﻟﻼﻛﺘﺸﺎف ﻷول ﻣﺮة ﰲ ﻋﺎم 2019 . اﻟ ﻛﺎﻧﺖ ﺪواﺋﺮ اﻟﺮادﻳﻮ ﻳﺔ اﻟﻔﺮدﻳﺔ ﻫﺎﺋﻠـﺔ ﺒﻠـﻎ ﻳ ﻋﺮﺿﻬﺎ ﻣﺌﺎت اﻟﻜﻴﻠـﻮ ﻓﺮﺳـﺦ ﻓﻠﻜـﻲ ﺣﻴـﺚ ﻳﺴـﺎوي ﻛﻴﻠـﻮ ﻓﺮﺳـﺦ ﻓﻠﻜـﻲ 2360 ﺳــﻨﺔ ) ﺿﻮﺋﻴﺔ ﻛﻤﺮﺟـﻊ ﻳﺒﻠـﻎ ﻋـﺮض ﻣﺠـﺮة درب اﻟﺘﺒﺎﻧﺔ ﺣﻮاﱄ 30 ﻛﻴﻠﻮ ﻓﺮﺳﺦ ﻓﻠﻜﻲ .( ﺗﻢ اﻗﱰاح ﻧﻈﺮﻳـ ﺎت ﻣﺘﻌـﺪدة ﻟـ ـ ﴩح أﺻـﻞ اﻟ ﺪواﺋﺮ اﻟﺮادﻳﻮ ﻳﺔ ﺑﻤﺎ ﰲ ذﻟﻚ اﻟﺴﺪم اﻟﻜﻮﻛﺒﻴـﺔ واﻧـﺪﻣﺎج اﻟﺜﻘـﻮب اﻟﺴــﻮداء ﻟﻜـﻦ اﻟﺒﻴﺎﻧـﺎت اﻟﺮادﻳﻮﻳﺔ وﺣﺪﻫﺎ ﻟﻢ ﺗﺘﻤﻜﻦ ﻣﻦ اﻟﺘﻤﻴﻴـﺰ ﺑـ اﻟﻨﻈﺮﻳﺎت . ﻛﺎﻧﺖ ﻛﻮﻳﻞ وﻣﻌﺎوﻧﻮﻫﺎ ﻣﻔﺘـﻮﻧ واﻋﺘﻘﺪوا أﻧﻪ ﻣﻦ ا ﻤﻜﻦ أن ﺗﻜـﻮن اﻟﺤﻠﻘـﺎت اﻟﺮادﻳﻮﻳﺔ ﺗﻄﻮر اً ﻣـﻦ ا ﺮاﺣـﻞ اﻟﻼﺣﻘـﺔ ﻣـﻦ ﻣﺠــﺮات اﻻﻧﻔﺠــﺎر اﻟﻨﺠﻤــﻲ اﻟﺘــﻲ ﻛــﺎﻧﻮا ﻳﺪرﺳـﻮﻧﻬﺎ . ﺑـﺪأوا اﻟﺒﺤـﺚ ﰲ ORC 4 - أول داﺋﺮة ﻳﺔ رادﻳﻮ ﻓﺮدﻳﺔ ﻳﺘﻢ اﻛﺘﺸـﺎﻓﻬ ﺎ وﻳﻤﻜـﻦ رﺻﺪﻫﺎ ﻣﻦ ﻧﺼﻒ اﻻرض اﻟﺸﻤﺎﱄ . ﺣﺘﻰ ذﻟﻚ اﻟﺤ ، ﻟﻢ ﻳﺘﻢ رﺻـﺪ اﻟـﺪواﺋﺮ إ ﻻ ﻣـﻦ ﺧـﻼل اﻧﺒﻌﺎﺛﺎﺗﻬﺎ اﻟﺮادﻳﻮﻳﺔ دون أي ﺑﻴﺎﻧﺎت ﺑ . ﴫﻳﺔ ـ اﺳـﺘﺨﺪم ﻓﺮﻳــﻖ ﻛﻮﻳــﻞ ﻣﻄﻴﺎﻓ ـ ﺎً ﻣﻼً ﻣﺘﻜــﺎ ﻟﻠﻤﺠـﺎﻻت ﰲ ﻣﺮﺻـﺪ ﻛﻴـﻚ ﻋـﲆ ﻗﻤـﺔ ﺟﺒـﻞ ﻬﺎواي ﺑ ﻣﻮﻧﺎﻛﻴﺎ ﻟﻠﻨﻈﺮ إﱃ اﻟـﺪاﺋﺮة اﻟﺮادﻳﻮﻳـﺔ ORC4 اﻟﺬي ﻛﺸﻒ ﻋﻦ ﻛﻤﻴﺔ ﻫﺎﺋﻠﺔ ﻣﻦ اﻟﻐﺎ ز ا ﻀﻐﻮط ﺷﺪﻳﺪ اﻹﺿﺎءة واﻟﺴﺎﺧﻦ أﻛﺜﺮ ﺑﻜﺜ ﻣﻤﺎ ﻳُﺮى ﰲ ا ﺠﺮة ا ﺘﻮﺳﻄﺔ . ﻣﻊ وﺟﻮد أﺳﺌﻠﺔ أﻛﺜﺮ ﻣﻦ اﻹﺟﺎﺑﺎت ﺑﺪأ اﻟﻔﺮﻳﻖ ﰲ اﻟﻌﻤ ـﻞ اﻟﺒﻮﻟﻴ ـ ﴘـ وﺑﺎﺳ ـﺘﺨﺪا م ﺑﻴﺎﻧ ـﺎت اﻟﺘ ﺼﻮﻳﺮ اﻟﺒﴫي واﻷﺷـﻌﺔ ﺗﺤـﺖ اﻟﺤﻤـﺮاء ﺣﺪدوا أن ﻋﻤﺮ اﻟﻨﺠﻮم داﺧـﻞ ﻣﺠـﺮة ORC 4 ﻳﺒﻠﻎ ﺣﻮاﱄ 6 ﻣﻠﻴﺎرات ﺳﻨﺔ . ﻗﺎل ﻛﻮﻳﻞ " : ﻛﺎن ﻫﻨﺎك اﻧﻔﺠﺎر ﰲ ﺷﻜ ﻞ ﻧﺠﻢ ﰲ اﻷﻳﻮﻧﺎت ﰲ ﻫﺬه ا ﺠﺮة ﻟﻜﻨﻪ اﻧﺘﻬﻰ ﻣﻨﺬ ﻣﻠﻴﺎر ﺳﻨﺔ ﺗﻘﺮﻳﺒ ".ﺎً ــــــ ﻗﺎﻣﺖ ﻛﺎﺳـﺎﻧﺪرا ﻟﻮﺗﺸـﺎس زﻣﻴﻠـﺔ ﻣـﺎ ﺑﻌـﺪ اﻟﺪﻛﺘﻮراه ﰲ ﻣﺮﻛﺰ ﻫﺎرﻓـﺎرد وﺳﻤﻴﺜﺴـﻮﻧﻴﺎن ﻟﻠﻔﻴﺰﻳ ـﺎء اﻟﻔﻠﻜﻴ ـﺔ ا ﺘﺨﺼﺼـﺔ ﰲ اﻟﺠﺎﻧ ـﺐ اﻟﻨﻈﺮي ﻟﻠﺮﻳﺎح ا ﺠﺮﻳﺔ وﻣﺆﻟﻔـﺔ ﻣﺸـﺎرﻛﺔ ﰲ اﻟﻮرﻗ ـﺔ، ﺑ ـﺈدارة ﻣﺠﻤﻮﻋ ـﺔ ﻣ ـﻦ ا ﺤﺎﻛ ـﺎة اﻟﺤﺎﺳﻮﺑﻴﺔ اﻟﺮﻗﻤﻴﺔ ﻟﻨﺴﺦ ﺣﺠﻢ وﺧ ﺼـﺎﺋﺺ اﻟﺪاﺋﺮة اﻟﺮادﻳﻮ ﻳﺔ ﺑﻤﺎ ﰲ ذﻟﻚ اﻟﻜﻤﻴـﺔ اﻟﻜﺒـ ة ﻣﻦ اﻟﻐﺎز اﻟﺒﺎرد واﻟـﺬي ﺗﻌـﺮض ﻟﻠﺼـﺪﻣﺔ ﰲ ا ﺠﺮة ا ﺮﻛﺰﻳﺔ . أﻇﻬﺮت ﻋﻤﻠﻴﺎت ا ﺤﺎﻛـﺎة أن اﻟﺮﻳﺎح ا ﺠﺮﻳﺔ ا ﺘﺪﻓﻘﺔ ﺗﻬﺐ ﺪة 200 ﻣﻠﻴﻮن ﺳﻨﺔ ﻗﺒﻞ أن ﺗﺘـﻮق و ﻋﻨـﺪﻣﺎ ﺗﻮﻗﻔـﺖ اﻟﺮﻳـﺎح اﺳﺘﻤﺮت اﻟﺼﺪﻣﺔ ا ﺘﺤﺮﻛـﺔ ﻟﻸﻣـﺎم ﰲ دﻓـﻊ اﻟﻐﺎز اﻟﺴﺎﺧﻦ ﺧﺎرج ا ﺠـﺮة وﻛﻮّﻧـﺖ ﺣﻠﻘـﺔ رادﻳﻮﻳﺔ ﰲ ﺣ أرﺳـﻠﺖ اﻟﺼـﺪﻣﺔ اﻟﻌﻜﺴـﻴﺔ اً ﺑﺎرد اً ﻏﺎز ﻳﺴﻘﻂ ﻣﺮة أﺧﺮى ﻋﲆ ا ﺠﺮة ﻘﺪ ﻟ . اﺳﺘﻐﺮﻗﺖ ﻋﻤﻠﻴـﺔ ا ﺤﺎﻛـﺎة أﻛﺜـﺮ ﻣـﻦ 750 ﻣﻠﻴﻮن ﺳﻨﺔ ﺿﻤﻦ ﻧﻄﺎق ﺗﻘﺪﻳﺮ ﻋﻤـﺮ اﻟـﻨﺠﻢ ORC 4 اﻟﺬي ﻳﺒﻠﻎ ﻣﻠﻴﺎر ﺳﻨﺔ . " ﻟﺘﻨﻔﻴـﺬ ﻫـﺬا اﻟﻌﻤﻞ ﺗ ﺤﺘﺎج إﱃ ﻣﻌﺪل ﺗﺪﻓﻖ ﻋﺎﱄ اﻟﻜﺘﻠ ﻣﻤﺎ ﺔ ﻳﻌﻨﻲ ﻗﺬف اﻟﻜﺜ ﻣﻦ ا ﻮاد ﺑﺴـ ـ ﺮﻋﺔ ﻛﺒـ ة وﻳ ﺠﺐ أن ﻳﻜﻮن اﻟﻐﺎز ا ﺤﻴﻂ ﺧـﺎرج ا ﺠـﺮة ﻣـﻨﺨﻔﺾ اﻟﻜﺜﺎﻓـﺔ وإﻻ ﺳـﺘﺘﻮﻗﻒ اﻟﺼـﺪﻣﺔ " ﻫﺬان ﻫﻤﺎ اﻟﻌﺎﻣﻼن اﻟﺮﺋﻴﺴﻴﺎن، " ﻗﺎل ﻛﻮﻳﻞ . " اﺗﻀﺢ أن ا ﺠﺮات اﻟﺘﻲ ﻛﻨﺎ ﻧﺪرﺳـﻬﺎ ﻟـﺪﻳﻬﺎ ﻣﻌﺪﻻت ﺗﺪﻓﻖ ﻋﺎﻟﻴـﺔ اﻟﻜﺘﻠـﺔ إﻻ إﻧﻬـﺎ ﻧـﺎدرة ﻟﻜﻨﻬﺎ ﻣﻮﺟﻮدة أﻋﺘﻘـ و ﺪ أن ﻫـﺬا ﻳﺸـ إﱃ أن ORCs ﺗﻨﺸﺄ ﻣﻦ ﻧﻮع ﻣﺎ ﻣﻦ اﻟﺮﻳـﺎ ح ا ﺠﺮﻳـﺔ ا ﺘﺪﻓﻘﺔ . ﻻ ﻳﻤﻜﻦ ﻟﻠﺮﻳﺎح ا ﺘﺪﻓﻘﺔ أن ﺗﺴـﺎﻋﺪ اﻟ ﻌﻠﻤﺎء ﻋﲆ ﻓﻬﻢ ORCs ﻓﺤﺴﺐ ﺑﻞ ﻳﻤﻜﻦ أن ﺗﺴ ﺎﻋﺪ ﻋﲆ ﻓﻬﻢ اﻟﺮﻳﺎح ا ﺘﺪﻓﻘﺔ أﻳﻀ .ﺎً ﻗﺎل ﻛﻮﻳﻞ " : ﺗﻮﻓﺮ ﻟﻨﺎ ORCs ﻃﺮﻳﻘـﺔ ﻟﺮؤﻳـﺔ اﻟﺮﻳﺎح ﻣﻦ ﺧﻼل اﻟﺒﻴﺎﻧﺎت اﻟﺮادﻳﻮﻳﺔ واﻟﺘﺤﻠﻴﻞ اﻟﻄﻴﻔﻲ ﻣﺎ ﻳﺴﺎﻋﺪﻧﺎ ﰲ ﺗﺤﺪﻳـﺪ ﻣـﺪى ﺷـﻴﻮع اﻟﺮﻳﺎح ا ﺠﺮ ﻳﺔ اﻟﺸﺪﻳﺪة وﻃﺒﻴﻌﺔ دورة ﺣﻴـﺎة اﻟﺮﻳﺎح إﺿﺎﻓﺔ ﻌﺮﻓﺔ ا ﺰﻳﺪ ﻋﻦ ﺗﻄﻮر ا ﺠﺮة : ﻫﻞ ﺗﻤﺮ ﺟﻤﻴﻊ ا ﺠـﺮات اﻟﻀـﺨﻤﺔ ﺑﻤﺮﺣﻠـﺔ ORC ؟ ﻫﻞ ﺗﺘﺤﻮل ا ﺠﺮات اﻟﺤﻠﺰوﻧﻴﺔ إﱃ ﺷﻜﻞ إﻫﻠﻴﻠﺠﻲ ﻋﻨﺪﻣﺎ ﺗﺘﻮﻗﻒ ﻋﻦ ﺗﻜﻮﻳﻦ اﻟﻨﺠﻮم؟ أﻋﺘﻘﺪ أن ﻫﻨﺎك اﻟﻜﺜ اﻟﺬي ﻳﻤﻜﻨﻨﺎ ﺗﻌﻠﻤﻪ ﻋﻦ اﻟﺪواﺋﺮ اﻟ ﺮادﻳﻮ ﻳﺔ اﻟﻨﺎدرة .