Free Astronomy Magazine November-December 2022 ARABIC VERSION

38 ASTRO PUBLISHING ones,” said Wren Suess, a cosmology fellow at the University of California Santa Cruz and a co-author of the paper. “We still don’t yet under- stand all of the processes that make galaxies stop forming stars, but this discovery shows just how powerful these major galaxy mergers are and how much they can affect how a galaxy grows and changes over time.” Because the new result is from a single observation, it is cur- rently unclear just how typical this tug-of-war and its resultant quies- cence may be. However, the discov- ery challenges long-held theories about how star formation stops and galaxies die and has provided scien- tists with an exciting new challenge: finding more examples. “While it’s pretty clear from this sys- tem that cold gas really can end up way outside of a merger system that shuts off a galaxy, the sample size of one galaxy tells us very little about how common this process is,” said David Setton, a graduate student in the department of physics and as- tronomy at the University of Pitts- burgh and a co-author of the paper. “But, there are many galaxies out there like J1448+1010 that we’re able to catch right in the middle of those crashes and study exactly what happens to them when they go through that stage. The ejection of cold gas is an exciting new piece of the quiescence puzzle, and we are excited to try to find more ex- amples of this.” Spilker added, “As- tronomers used to think that the only way to make galaxies stop forming stars was through violent, fast processes, like a bunch of super- novae exploding in the galaxy to blow most of the gas out of the galaxy and heat the rest. Our obser- vations show that it doesn’t take a ‘flashy’ process to cut off star forma- tion. The much slower merging process can also put an end to star formation and galaxies.”    NOVEMBER-DECEMBER 2022 ﺠﻠﺔ ﻣ Astronomy ﺎﻟﻌﺮ ﺔ ٣٨ " ﻣﺎ زﻟﻨﺎ ﻻ ﻧﻔﻬﻢ ﺣﺘﻰ اﻵن ﺟﻤﻴﻊ اﻟﻌﻤﻠﻴـﺎت اﻟﺘﻲ ﺗﺠﻌﻞ ا ﺠـﺮات ﺗﺘﻮﻗـﻒ ﻋـﻦ ﺗﺸـﻜﻴﻞ اﻟﻨﺠﻮم ، وﻟﻜﻦ ﻫﺬا اﻻﻛﺘﺸﺎف ﻳﻮﺿﺢ ﻣـﺪى ﻗﻮة اﻧـﺪﻣﺎﺟﺎت ا ﺠـﺮات اﻟﺮﺋﻴﺴـﻴﺔ وﻣـﺪى ﺗﺄﺛ ﻫﺎ ﻋﲆ ﻛﻴﻔﻴـﺔ ﻧﻤـﻮ ا ﺠـﺮة وﺗﻐ ﻫـﺎ ﺑﻤﺮور اﻟﻮﻗﺖ ". ﻧﻈﺮًا ﻷن اﻟﻨﺘﻴﺠـﺔ اﻟﺠﺪﻳـﺪة ﻣﺄﺧﻮذ ة ﻣﻦ ﻣﻼﺣﻈـﺔ واﺣـﺪة ، ﻓﻤـﻦ ﻏـ اﻟﻮاﺿﺢ ﺣﺎﻟﻴًـﺎ ﻣـﺪى ﻧﻤﻮذﺟﻴـﺔ ﻟﻌﺒـﺔ ﺷـﺪ اﻟﺤﺒﻞ ﻫﺬه واﻟﻬﺪوء اﻟﻨﺎﺗﺞ ﻋﻨﻬﺎ . وﻣـﻊ ذﻟـﻚ ﻓـﺈن ﻫـﺬا اﻻﻛﺘﺸـﺎف ﻳﺘﺤـﺪى اﻟﻨﻈﺮﻳ ـﺎت اﻟﻘﺪﻳ ﻤﺔ ﺣﻮل ﻛﻴﻔﻴﺔ ﺗﻮﻗﻒ ﺗﺸـﻜﻞ اﻟﻨﺠـﻮم وﻣﻮت ا ﺠﺮا ت ، وﻗـﺪ ﻗـﺪم ﻟﻠﻌﻠﻤـﺎء ﺗﺤـﺪﻳًﺎ : ﺟﺪﻳﺪًا ﻣﺜ ًا اﻟﻌﺜﻮر ﻋﲆ ا ﺰﻳﺪ ﻣﻦ اﻷﻣﺜﻠﺔ . ﻗﺎل د ﻳﻔﻴﺪ ﺳﻴﺘﻮن " : ﰲ ﺣ أﻧﻪ ﻣﻦ اﻟﻮاﺿﺢ ﺟﺪًا ﻣﻦ ﻫﺬا اﻟﻨﻈﺎم أن اﻟﻐﺎز اﻟﺒﺎرد ﻳﻤﻜﻦ أن ﻳﻨﺘﻬﻲ ﺑﻪ اﻷﻣﺮ ﺑﻌﻴﺪًا ﻋﻦ ﻧﻈﺎم اﻻﻧﺪﻣﺎج اﻟﺬي ﻳﻐﻠﻖ ﻣﺠﺮة ، ﻓﺈن ﺣﺠﻢ ﻋﻴﻨﺔ إﺣﺪى ا ﺠﺮات ﻻ ﻳﺨﱪﻧـﺎ ﻛﺜ ـ ًا ﻋـﻦ ﻣـﺪى ﺷـﻴﻮع ﻫـﺬه اﻟﻌﻤﻠﻴـﺔ " ﺑﺤﺴـﺐ دﻳﻔﻴـﺪ ﺳـﻴﺘﻮن ﻃﺎﻟـﺐ اﻟ ﺪراﺳﺎت اﻟ ﻌﻠﻴﺎ ﰲ ﻗﺴـﻢ اﻟﻔﻴﺰﻳـﺎء واﻟﻔﻠـﻚ ﺑ ﺠﺎﻣﻌﺔ ﺑﻴﺘﺴﱪغ وﻣﺆﻟﻒ ﻣﺸـﺎرك ﻟﻠﻮرﻗـﺔ اﻟﺒﺤﺜﻴﺔ . " وﻟﻜﻦ ﻫﻨﺎك اﻟﻌﺪﻳﺪ ﻣﻦ ا ﺠﺮات ﻣﺜﻞ ا ﺠﺮة J1448 + 1010 اﻟﺘــﻲ ﻳﻤﻜﻨﻨــﺎ رﺻــﺪﻫﺎ ﻣﺒــﺎﴍة ﰲ ﻣﻨﺘﺼــﻒ ﺗﻠــﻚ اﻻﺻــﻄﺪاﻣﺎت ودراﺳﺔ ﻣﺎ ﻳﺤﺪث ﻟﻬﺎ ﺑﺎﻟﻀﺒﻂ ﻋﻨـﺪﻣﺎ ﺗﻤـﺮ ﻋﱪ ﺗﻠﻚ ا ﺮﺣﻠﺔ . إن ﻃﺮد اﻟﻐـﺎز اﻟﺒـﺎرد ﻫـﻮ ﻗﻄﻌﺔ ﺟﺪﻳﺪة وﻣﺜ ة ﻣﻦ ﻟﻐﺰ اﻟﻬﺪوء ، وﻧﺤﻦ ﻣﺘﺤﻤﺴﻮن ﻟ ﻠﻌﺜﻮر ﻋﲆ ﻣﺰﻳﺪ ﻣﻦ اﻷﻣﺜﻠﺔ ﻋﲆ ". ذﻟﻚ وأﺿﺎف ﺳﺒﻴﻠﻜﺮ " : اﻋﺘـﺎد اﻟﻔﻠﻜﻴـﻮن ﻋﲆ اﻻﻋﺘﻘﺎد ﺑﺄن اﻟﻄﺮﻳﻘﺔ اﻟﻮﺣﻴﺪة ﻹﻳﻘـﺎف ﺗﺸﻜﻴﻞ ا ﺠﺮات ﻟﻠﻨﺠـﻮم ﻛﺎﻧـﺖ ﻣـﻦ ﺧـﻼل ﻋﻤﻠﻴـﺎتﴎﻳﻌـﺔ وﻋﻨﻴﻔـﺔ ، ﻣﺜـﻞ اﻧﻔﺠـﺎر ﻣﺠﻤﻮﻋﺔ ﻣﻦ ا ﺴﺘﻌﺮات اﻟﻌﻈﻤﻰ ﰲ ا ﺠـﺮة ﻹﺧﺮاج ﻣﻌﻈﻢ اﻟ ﻐﺎز ﻣﻦ ا ﺠـﺮة واﻟﺤـﺮارة . اﻟﺒﻘﻴﺔ . ﺗﻈﻬﺮ ﻣﻼﺣﻈﺎﺗﻨﺎ أن اﻷﻣﺮ ﻻ ﻳﺘﻄﻠـﺐ " ﻋﻤﻠﻴﺔ ﻣﺒﻬﺮﺟـﺔ " ﻟﻘﻄـﻊ ﺗﺸـﻜﻞ اﻟﻨﺠـﻮم ﻳﻤﻜﻦ ﻟﻌﻤﻠﻴﺔ اﻻﻧﺪﻣﺎج اﻷﺑﻄﺄ ﺑﻜﺜ أﻳﻀًﺎ أن ﺗﻀﻊ ﺣﺪاً ﻟﺘﺸﻜﻴﻞ اﻟﻨﺠﻮم وا ﺠﺮات ." ﻟ ﻠ ﺔ ﺻﻮرة ﻣﺬﻫﻠﺔ ﻟﻤﺼﻔﻮﻓﺔ ﻫﻮاﺋ ﺎت ﻣﺮﺻﺪ أﻟﻤﺎ ﻓﻲﻫﻀ ﺔﺷ ﻨﺎﻧﺘﻮرﺗﺤﺖ در اﻟﺘ ﺎﻧﺔ . SDSS J1448 + 1010 ﻫـﻲ ﻣﺠـﺮة ﺿـ ﻤﺔ ﺧﺎﻣﻠــﺔ ــﻮن ﻓـﻲ ﻧﺼــﻒ ــﺎن اﻟ وﻟـﺪت ﻋﻨـﺪﻣﺎ ﻋﻤـﺮﻩ ـ اﻟــــ ًــــﺎ و ﺤﺎﻟﻲ ﺗﻘﺮ ﺗ ﻮﺷــــﻚ ﻋﻠــــﻰ اﻻﻧﺘﻬــــﺎء ﻣــــﻦ اﻻ ﻧــــﺪﻣﺎج ﻣــــﻊ ﻣﺠــــﺮة أﺧــــﺮى . ﺧــــﻼل ﻫــــﺬا اﻻﻧــــﺪﻣﺎج دﻓﻌـــﺖ ﻗـــﻮة اﻟــــ ـ ـــﺪًا ﻋــــﻦ ﺠﺎذﺑ ﺔ ﻣـــﺎ ﻘــــﺮ ﻣـــﻦ ﻧﺼــــﻒ اﻟﻐـــﺎزات اﻟﻤ ﻮﻧـــﺔ ﻟﻠﻨﺠــــﻮم ﻓـــﻲ اﻟﻨﻈــــﺎم ﻌ ـﺪة ـﻮﻳﻦ ﻧﺠـﻮم ﺟﺪ اﻟﻤﺠﺮة ، ﻣﻤﺎ ﺟﻌﻠﻬﺎ ﻏ ﻗﺎدرة ﻋﻠﻰ ﺗ . ـﺔ ﺑ ﺎﻧـﺎت ﺗ ﻤـﻊ ﻫـﺬﻩ اﻟﺼـﻮرة اﻟﻤﺮﻛ زرﻗـــﺎء / ﺑ ﻀـــﺎء ﻣـــﻦ ﺗﻠﺴـــ ﻮب ﻫﺎﺑـــﻞ اﻟﻔﻀـــﺎﺋ ﻲ وﺑ ﺎﻧـــﺎت ﻤـــﺮاء ﺑﺮ/ ـــﺔ ﻣـــﻦ ﻣﺼـــﻔﻮﻓﺔ أﺗﺎ ﺎﻣـــﺎ ﻘﺎﻟ ﻛﺒــ ة اﻟﻤﻠ ﻤــ / ﻣــﺎ دون اﻟﻤﻠ ﻤــ أﻟﻤــﺎ )ي ( ﻹﻇﻬــﺎراﻟﺘﻮز ــﻊ ﻌــﺪ اﻻﻧــﺪﻣﺎج ﻟﻠﻐــﺎزواﻟﻨﺠــﻮم ﻣــﻦ اﻟﻤﺠﺮة اﻟ ـ ﺨﺎﻣﻠﺔ اﻵن إﻟﻰ ﺗ ﺎرات ﻣﻦ اﻟﻤﻮاد اﻟﻤﻌﺮوﻓﺔ ﺎﺳﻢ ذﻳﻮل اﻟﻤﺪ واﻟ ـ .ﺠﺰر ﻧﻮﻓﻤ دﻳﺴﻤ 2022