Free Astronomy Magazine January-February 2024 ARABIC VERSION

“When I first saw evidence for a ro- tating structure in the ALMA data I could not believe that we had de- tected the first extragalactic accre- tion disc, it was a special moment,” says Anna McLeod, an associate pro- fessor at Durham University in the UK and lead author of the study published in Nature . “We know discs are vital to forming stars and planets in our galaxy, and here, for the first time, we’re seeing direct evidence for this in another galaxy.” This study follows up observations with the Multi Unit Spectroscopic Explorer (MUSE) instrument on ESO’s Very Large Telescope (VLT), which spotted a jet from a forming star — the system was named HH 1177 — deep inside a gas cloud in the Large Magellanic Cloud. “We discovered a jet being launched from this young massive star, and its presence is a signpost for ongoing disc accretion,” McLeod says. But to confirm that such a disc was indeed present, the team needed to meas- ure the movement of the dense gas around the star. As matter is pulled towards a grow- ing star, it cannot fall directly onto it; instead, it flattens into a spinning disc around the star. Closer to the centre, the disc rotates faster, and this difference in speed is the smok- ing gun that shows astronomers an accretion disc is present. “The frequency of light changes de- pending on how fast the gas emit- ting the light is moving towards or away from us,” explains Jonathan Henshaw, a research fellow at Liver- pool John Moores University in the UK, and co-author of the study. “This is precisely the same phenom- enon that occurs when the pitch of JANUARY-FEBRUARY 2024 ُﻈﻬﺮ ﻫﺬا اﻟﺮﺳﻢ اﻟﺘﺨ ﻠﻲ اﻟ ﻨﻈﺎم HH 1177 اﻟـﺬ ﻳﻮﺟـﺪ ﻓـﻲﺳـﺤﺎ ﺔ ﻣـﺎﺟﻼن اﻟﻜـ ى وﻫـﻲﻣﺠـﺮة ﻣﺠﺎورة ﻟﻤﺠﺮﻨﺎ . ـ ﻘﻮم اﻟ ﺠﺴﻢ اﻟﻨ ﻤﻲ اﻟﺼﻐ واﻟﻀ ﻢ اﻟﻤﺘﻮﻫﺞ ﻓﻲاﻟﻤﺮﻛﺰﺑ ﻤﻊ اﻟ ﻤﺎدة ﻣﻦﻗﺮص ﻣﻐ ﺑ ﻨﻤﺎ ﻘ ﺎً ﻮم أ ﻀ اﻟ ﻘﺬف ـﺔ ﻤﺎدة ﻓﻲ ﻧﻔﺎﺛﺎت ﻗﻮ و ﺎﺳـﺘﺨﺪام ﻣﺼـﻔﻮﻓﺔ أﺗﺎ ﺎﻣـﺎ ا ـﺔ ﻟﻤﻠ ﻤ دون / ـﺔ اﻟﻜﺒــ اﻟﻤﻠ ﻤ ( أﻟﻤـﺎ ) ﺸــﺎركﻓﻴﻬـﺎ اﻟﻤﺮﺻــﺪ اﻷوروﺑــﻲ اﻟـ اﻟــ ـ ﺠﻨﻮﺑﻲ ﺗﻤﻜـﻦ ﻓﺮ ــﻖ ﻣـﻦ ﻋﻠﻤـﺎء اﻟﻔﻠــﻚ ﻣﻦ اﻟﻌﺜﻮر ﻋﻠﻰدﻟﻴﻞ ﻋﻠﻰوﺟﻮد ﻫﺬا اﻟﻘﺮصﻣﻦ ﺧﻼل ﻣﺮاﻗ ﺔ دوراﻧﮫ . ﻫـﺬﻩ ﻫـﻲ اﻟﻤـﺮة اﻷوﻟـﻰ اﻟـ ﺘﻢ ـﻢﺷـﺎب ﻓﻴﻬﺎ اﻛﺘﺸﺎفﻗﺮصﺣﻮل ﻧ - ﺗﺸـ ﻞ اﻟ ﻮاﻛـﺐ ﻓـﻲ وﻫـﻮ ﻧـﻮع اﻟﻘـﺮص اﻟﻤﻄـﺎﺑﻖ ﻟﺘﻠـﻚ اﻟـ - ﻣﺠﺮﻨﺎ ﻓﻲﻣﺠﺮة أﺧﺮى . ﺗﻘـﻮل آﻧـﺎ ﻣﺎﻛﻠﻮﻳـﺪ اﻷﺳــﺘﺎذة ا ﺸـﺎرﻛﺔ ﰲ ﺟﺎﻣﻌﺔ دور ﻫﺎم ﰲ ا ﻤﻠﻜﺔ ا ﺘﺤﺪة وا ﺆﻟﻔـﺔ ا ﻟﺮﺋﻴﺴﻴﺔ ﻟﻠﺪراﺳﺔ ا ﻨﺸﻮرة ﰲ ﻣﺠﻠ ﺔ ﻧﻴﺘﴩ : " ﻋﻨﺪﻣﺎ رأﻳﺖ ﻷول ﻣﺮة دﻟﻴﻼً ﻋﲆ وﺟﻮد ﺑﻨﻴﺔ دوارة ﰲ ﺑﻴﺎﻧﺎت ﻣﺮﺻﺪ أ ـﺎ ﻟـﻢ أﺳـﺘﻄﻊ أن أﺻـﺪق أﻧﻨـﺎ اﻛﺘ ﺸـﻔﻨﺎ أول ﻗـﺮص ﺗﺮاﻛﻤـﻲ ﺧﺎرج ا ﺠﺮة ﻟﻘﺪ ﻛﺎﻧﺖ ﻟﺤﻈﺔ ﺧﺎﺻﺔ ﻧﺤﻦ ". ﻧﻌﻠﻢ أن اﻷﻗﺮاصﴐورﻳﺔ ﻟﺘﺸﻜﻴﻞ اﻟﻨ ﺠـﻮم واﻟﻜﻮاﻛﺐ ﰲ ﻣﺠﺮﺗﻨﺎ، وﻫﻨﺎ وﻷول ﻣﺮة ﻧـﺮى دﻟﻴﻼً ﻣﺒﺎﴍاً ﻋﲆ ذﻟﻚ ﰲ ﻣﺠﺮة أﺧﺮى . ﺗﺘﺎﺑﻊ ﻫــﺬه اﻟﺪراﺳــﺔ اﻷرﺻــﺎد ﺑﺎﺳــﺘﺨﺪام أداة ا ﺴﺘﻜﺸﻒ اﻟﻄﻴﻔﻲ ﻣﺘﻌﺪد اﻟﻮﺣﺪات ( ﻣﻮس) ا ﺘﺼـﻞ ﺑ ﺎﻟﺘﻠﺴـﻜﻮب اﻟﻜﺒـ ﺟـﺪ ا اً ﻟﺘـﺎﺑﻊ ﻟﻠﻤ ﺮﺻﺪ اﻷوروﺑـﻲ اﻟﺠﻨـﻮﺑﻲ واﻟـﺬي رﺻـﺪ ﺎً ﺗﺪﻓﻘ ﻣﻦ ﻧﺠـﻢ ﻣﺘﺸـﻜﻞ وﻗـﺪ ﺗـﻢ ﺗ ﺴـﻤﻴﺔ اﻟﻨﻈﺎم ﺑﺎﺳﻢ HH 1177 - ﰲ أﻋﻤﺎق ﺳﺤﺎﺑﺔ ﻏﺎزﻳـﺔ ﰲ ﺳـﺤﺎﺑﺔ ﻣــﺎﺟﻼن اﻟﻜـﱪى . ﻟﻘـﺪ اﻛﺘﺸﻔﻨﺎ ﻧﻔﺎﺛﺔ ﺗﻨﻄﻠﻖ ﻣﻦ ﻫﺬا اﻟﻨﺠﻢ اﻟﺸﺎب اﻟﻀﺨﻢ وﻳﻌﺪ وﺟﻮدﻫـﺎ ﻋﻼﻣـﺔ ﻋـﲆ ﺗـﺮاﻛﻢ ـــــ ﺑﻮاﺳﻄﺔ اﻟﻘﺪرات اﻟﻤﺸ ﻛﺔ ﻟ ﻠﺘﻠﺴـ ﻮ اﻟﻜﺒـ ﺟـﺪ ب اً اﻟﺘـﺎﺑﻊ ﻟﻠﻤﺮﺻـﺪ اﻷوروﺑـﻲ اﻟــﺠﻨﻮﺑﻲ و ﻣﺼـﻔﻮﻓﺔ " ﻣﺮﺻﺪ أﺗﺎ ﺎﻣﺎ اﻟﻤﻠ ﻤ ي / ﺗﺤـﺖ اﻟﻤﻠ ﻤـ ي اﻟﻜﺒـ واﻟـ ﻌـﺪ ﺬ اﻟﻤﺮﺻـﺪ اﻷوروﺑـﻲ اﻟــﺠﻨﻮﺑﻲ ﺎً ﺷـﺮ ـﮫ ﻓ ﺗﻢ رﺻﺪ ﻗﺮصﺣﻮل ﻧ ﻢﺷﺎبﺿ ﻢ ﻓﻲﻣﺠﺮة أﺧﺮى . أﺟﺮاﻫـﺎ اﻟﻤﺴﺘﻜﺸـﻒ ـﺎت اﻟﺮﺻـﺪ اﻟـ ﺗُﻈﻬﺮﻋﻤﻠ اﻟﻄ ﻔﻲﻣﺘﻌﺪد اﻟﻮﺣﺪات ( ﻣـﻮس) اﻟﻤﺘﺼـﻞ ﺎﻟ ﺘﻠﺴـ ﻮب اﻟﻜﺒـ ﺟـﺪ اً ، ﻋﻠـﻰ اﻟ ﺴـﺎر، ﺗﻮﺟـﺪ اﻟﺴـﺤﺎ ﺔ اﻷم LHA 120-N 180B ﺗــﻢ ﻓﻴﻬــﺎ رﺻــﺪ ﻫــﺬا اﻟﻨﻈـﺎم اﻟــ اﻟﻤﺴــﻤﻰ HH 1177 ﻷول ﻣــﺮة . اﻟﺼــﻮرة ﻓــﻲ اﻟﻮﺳـﻂ ﺗﻈﻬــﺮ اﻟﻨﻔﺎﺛــﺔ اﻟﻤﺼــﺎﺣ ﺔ ﻟﻬـﺎ ـ اﻟــ . ﺠﺰء اﻟﻌﻠــﻮيﻣــﻦ اﻟ ﻨﻔﺎﺛــﺔ ﻣﻮﺟــﮫ ﻧﺤﻮﻧـﺎ ﻗﻠــ ﻼً و ﺎﻟﺘــﺎﻟﻲ ﺘﺤــﻮل إﻟــﻰ اﻟﻠـــﻮن اﻷزرق ـ اﻟـــ ﻣـــﺎ أ ﺠﺰء اﻟﺴــﻔﻠﻲ ﻓ اﺟـــﻊ ﻋﻨـــﺎ و ﺎﻟﺘـــﺎﻟﻲ ـــ اح ﻧﺤــﻮ اﻷ ﻤـــﺮ . ﻛﺸـــﻔﺖ اﻷ ﻣـــﻦ رﺻـــﺎد (ﺎ أﻟﻤ) ﻋﻦ اﻟﻘﺮص اﻟﺪوارﺣﻮل اﻟﻨ ﻢ ﻋﻠﻰ اﻟ ﻤ و ﺎﻟﻤﺜﻞ ﻣﻊ ﺗﺤﺮك اﻟ ـ ﺠﻮاﻧﺐ ﻧﺤﻮﻧﺎ و ﻌ ﺪ .ﻋﻨﺎ اً اﻟﻘﺮص ا ﺴﺘﻤﺮ ﻟﺘﺄ أ ﺟﻞ وﻣﻦ أ ﻛﺪ ﻣﻦ وﺟـﻮد ﻣﺜﻞ ﻫﺬا اﻟﻘﺮص ﺑﺎﻟﻔﻌﻞ اﺣﺘـﺎج اﻟﻔﺮﻳـﻖ إﱃ ﻗﻴﺎس ﺣﺮﻛﺔ اﻟﻐـﺎز اﻟﻜﺜﻴـﻒ ﺣـﻮل اﻟـﻨﺠﻢ . ﻋﻨﺪﻣﺎ ﺗﻨﺠـﺬب ا ـﺎدة ﻧﺤـﻮ ﻧﺠـﻢ ﻳﻨﻤـﻮ ﻻ ﻳﻤﻜﻨﻬﺎ أن ﺗﺴﻘﻂ ﻋﻠﻴﻪ ﻣﺒﺎﴍة وﺑـﺪﻻً ﻣـﻦ ذﻟﻚ ﻓﺈﻧﻪ ﻳﺘﺴﻄﺢ ﻟﻴﺸﻜﻞ ﻗﺮﺻ ﺎً اً دوار ﺣـﻮل اﻟﻨﺠﻢ . ﺑﺎﻟﻘﺮب ﻣﻦ ا ﺮﻛﺰ ﻳﺪور اﻟﻘﺮص ﺑﺸﻜﻞ أﴎع وﻫﺬا اﻻﺧﺘﻼف ﰲ اﻟﴪﻋﺔ ﻫﻮ دﻟﻴﻞ ﰲ ﻏﺎﻳـﺔ اﻷﻫﻤﻴﺔ ﻳﻮﺿﺢ ﻟﻌﻠﻤﺎء اﻟﻔﻠﻚ وﺟـﻮد ﻗـﺮص ﺗﺮاﻛﻤﻲ . ﻳﻮﺿـﺢ ﺟﻮﻧﺎﺛـﺎن ﻫﻨﺸـﻮ زﻣﻴـﻞ ﺑﺎﺣـﺚ ﰲ ﺟﺎﻣﻌﺔ ﺟﻮن ﻣـ ﻮرس ﰲ ﻟﻴﻔﺮﺑـﻮل ﺑﺎ ﻤﻠﻜـﺔ ا ﺘﺤﺪة وا ﺆﻟﻒ ا ﺸﺎرك : » ﻳﺘﻐ ﺗ ﺮدد اﻟﻀﻮء إ اً ﻋﺘﻤﺎد ﻋﲆ ﻣﺪى ﴎﻋﺔ ﺗﺤﺮك اﻟﻐﺎز ا ﻨﺒﻌﺚ ﻣـﻦ اﻟﻀـﻮء ﻧﺤﻮﻧـ ﺎ أو .«ﻋﻨﺎ اً ﺑﻌﻴﺪ ﻟﺘﻘﺮﻳﺐ اﻟﺼﻮرة ﻓـﺎن ﻫـﺬه اﻟﺪراﺳـ ﻫـﻲ ﺔ ﺑﺎﻟﻀﺒﻂ ﻧﻔﺲ اﻟﻈﺎﻫﺮة اﻟﺘﻲ ﺗﺤﺪث ﻋﻨـﺪﻣﺎ ــ ﻳﻨﺎﻳﺮ ﻓﺒﺮﺍﻳﺮ 2 0 2 4