Free Astronomy Magazine January-February 2024 ARABIC VERSION

I Gas recycling process near a supermas s si i ve e black hole u u nveiled by ALMAObservatory Bárbara Ferreira n a scientific breakthrough, an in- ternational team of scientists has delved into the heart of the Circi- nus Galaxy’s active galactic nucleus using the Atacama Large Millime- ter/submillimeter Array (ALMA). Achieving an unprecedented resolu- tion of about one light-year, the re- search has illuminated the intricate dance of gas flows around the galaxy’s supermassive black hole, en- compassing plasma, atomic, and mo- lecular phases. Notably, the team has elucidated the accretion flow — driven by a mechanism termed “gravitational instability”— that feeds the black hole. Intriguingly, not all this gas contributes to the black hole’s growth. A significant fraction is ejected as atomic or mo- lecular outflows, only to return and again be drawn towards the black hole in a cyclical pattern reminiscent of a water fountain. This profound discovery paves the way for a more holistic grasp of the growth dynam- ics of supermassive black holes. At the centers of many massive galax- ies, there exist “supermassive black holes” with masses exceeding a mil- lion times that of the Sun. How are these supermassive black holes formed? One of the crucial growth mechanisms proposed by previous research is “gas accretion” onto the black hole. This refers to how gas in the host galaxy somehow falls to- ward the central black hole. The gas that gathers very close to su- permassive black holes is accelerated at high speeds due to the gravity of the black hole. Due to intense fric- tion between gas particles, this gas heats up to several million degrees and emits brilliant light. This phe- nomenon is known as an active galactic nucleus (AGN), and its brightness can sometimes surpass the combined light of all the stars in the galaxy. Interestingly, a portion of the gas that falls towards the black hole (accretion flow) is thought to be blown away by the immense energy of this active galac- tic nucleus, leading to outflows. Both theoretical and observational studies have provided detailed in- sights into gas accretion mechanisms from the 100,000 light-year scale of the galaxies down to a scale of a few hundred light-years at the center. However, the gas accretion within JANUARY-FEBRUARY 2024 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 38 ـﺔ إﻋـﺎدة اﻟﻜﺸـﻒﻋـﻦﻋﻤﻠ ـــــﺎﻟﻘﺮ ﻣـــــﻦ ﺗـــــﺪوﻳﺮاﻟﻐـــــﺎز ﺛﻘﺐ أﺳﻮدﻫﺎﺋﻞ اﻟﻜﺘﻠﺔ : ﻘﻠﻢ ﺎر ﺮا ﻓ ﺮا ﻣﺮﺻﺪ أﻟﻤﺎ ﻓـﻲ إﻧﺠﺎز ﻋﻠﻤﻲ ﻛﺒ ﻗﺎم ﻓﺮﻳﻖ دوﱄ ﻣـﻦ اﻟﻌﻠﻤﺎء ﺑﺎﻟﺒﺤﺚ ﰲ ﻗﻠﺐ ﻧﻮاة ا ﺠﺮة اﻟﻨﺸـﻄﺔ ﰲ ﻣﺠ ـﺮة اﻟﺒﻴﻜ ـﺎر ﺑﺎﺳـﺘﺨﺪام ﻣﺼ ـﻔﻮﻓﺔ أﺗﺎﻛﺎﻣﺎ ا ﻠﻴﻤﱰﻳﺔ / ﺗﺤﺖ ا ﻠﻴﻤﱰﻳـﺔ اﻟﻜﺒـ ة ) أ ﺎ ﻣﺮﺻﺪ .( و ﻣﻦ ﺧﻼل ﺗﺤﻘﻴﻖ دﻗﺔ ﻏ ﻣﺴـ ﺒﻮﻗﺔ ﺗﺒﻠـﻎ ﺣﻮاﱄ ﺳﻨﺔ ﺿﻮﺋﻴﺔ واﺣﺪة . ﺳﻠﻂ اﻟﺒﺤﺚ اﻟﻀﻮء ﻋﲆ اﻟﺮﻗﺼـﺔ ا ﻌﻘـﺪة ﻟﺘﺪﻓﻘﺎت اﻟﻐﺎز ﺣﻮل اﻟﺜﻘﺐ اﻷﺳﻮد اﻟﻬﺎﺋﻞ ﰲ ا ﺠــﺮة واﻟــﺬي ﻳﺸــﻤﻞ ا ﺮاﺣـ ﻞ اﻟﺒﻼزﻣﻴ ـﺔ واﻟﺬرﻳﺔ واﻟﺠﺰﻳﺌﻴﺔ . ﻟﻘﺪ ﴍح اﻟﻔﺮﻳـﻖ ﺑـﺄن ﺗﺪﻓﻖ اﻟﱰاﻛﻢ اﻟﻨﺎﺗﺞ ﻋﻦ آﻟﻴﺔ ﺗﺴـﻤﻰ ﻋـﺪم " اﺳـﺘﻘﺮار اﻟﺠﺎذﺑﻴـ " ﺔ واﻟﺘـﻲ ﺗﻐـﺬي اﻟﺜﻘـﺐ اﻷﺳﻮد . ﻣﻦ ا ﺜ ﻟﻼﻫﺘﻤﺎم أن ﻛﻞ ﻫﺬا اﻟﻐـﺎز ﻻ ﻳﺴﺎﻫﻢ ﰲ ﻧﻤﻮ اﻟﺜﻘﺐ اﻷﺳﻮد . ﻳﺘﻢ ﻗﺬف ﺟﺰء ﻛﺒ ﻣﻨ ﻪ ﻋﲆ ﺷﻜﻞ ﺗـﺪﻓﻘﺎت ذرﻳﺔ أو ﺟﺰﻳﺌﻴﺔ ﺛﻢ ﻳﻌﻮد وﻳﻨﺠﺬب ﻣﺮة أﺧﺮى ﻧﺤﻮ اﻟﺜﻘﺐ اﻷﺳـﻮد ﰲ ﻧﻤـﻂ دوري ﻳـﺬﻛﺮﻧﺎ ﺑﻨﺎﻓﻮرة ا ﺎء . ﻳﻤﻬـﺪ ﻫـﺬا اﻻﻛﺘﺸـﺎف ا ﻬـﻢ اﻟﻄﺮﻳﻖ ﻟﻔﻬﻢ أﻛﺜـﺮ ﺷـﻤﻮﻟﻴﺔ ﻟـﺪﻳﻨﺎﻣﻴﻜﻴﺎت ﻧﻤﻮ اﻟﺜﻘﻮب اﻟﺴﻮداء ﻓﺎﺋﻘﺔ اﻟﻜﺘﻠﺔ ﰲ اﻟﻜﻮن . ـ ﻳﻮﺟﺪ ﰲ ﻣﺮاﻛﺰ اﻟﻌﺪﻳﺪ ﻣﻦ ا ﺠﺮات اﻟﻀـﺨﻤﺔ » ﺛﻘﻮب ﺳﻮداء ﻫﺎﺋﻠﺔ اﻟﻜﺘﻠﺔ « ﻛﺘﻠﺘﻬﺎ ﺗﺘﺠﺎوز ﻣﻠﻴﻮن ﻣﺮة ﻛﺘﻠﺔ اﻟﺸﻤﺲ . ﻛﻴﻒ ﺗﺘﺸﻜﻞ ﻫ ﺬه اﻟﺜﻘﻮب اﻟﺴﻮداء اﻟﻬﺎﺋﻠﺔ؟ إﺣﺪى آﻟﻴﺎت اﻟﻨﻤـﻮ اﻟﺤﺎﺳﻤﺔ اﻟﺘﻲ اﻗﱰﺣﺘﻬﺎ اﻷﺑﺤـﺎث اﻟﺴـﺎﺑﻘﺔ "ﻫﻲ ﺗﺮاﻛﻢ اﻟﻐﺎز " ﰲ اﻟﺜﻘﺐ اﻷﺳـﻮد . ﻳﺸـ ﻫﺬا إﱃ ﻛﻴﻔﻴﺔ ﺳﻘﻮط اﻟﻐﺎز ا ﻮﺟﻮد ﰲ ا ﺠﺮة ا ﻀﻴﻔﺔ ﺑﻄﺮﻳﻘﺔ ﻣﺎ ﺑﺎﺗﺠﺎه اﻟﺜﻘـﺐ اﻷﺳـﻮد ا ﺮﻛﺰي وﻳﺘﺴﺎرع اﻟﻐﺎز اﻟﺬي ﻳﺘﺠﻤﻊ ﺑﺎﻟﻘﺮب ﻣﻦ اﻟﺜﻘﻮب اﻟﺴﻮ داء ﻓﺎﺋﻘﺔ اﻟﻜﺘﻠﺔ ﺑﺴ ﺮﻋﺎت ـ ﻋﺎﻟﻴﺔ ﺑﺴﺒﺐ ﺟﺎذﺑﻴﺔ اﻟﺜﻘﺐ اﻷﺳﻮد وﺑﺴـﺒﺐ اﻻﺣﺘﻜﺎك اﻟﺸﺪﻳﺪ ﺑ ﺟﺰﻳﺌﺎت اﻟﻐﺎز، ﻳﺴﺨﻦ ﻫﺬا اﻟﻐﺎز ﺣﺘﻰ ﻋﺪة ﻣﻼﻳـ ﻣـﻦ اﻟـﺪرﺟﺎت وﻳﺒﻌﺚ ﺿﻮءا ﺳﺎﻃﻌﺎ . ﺗُﻌﺮف ﻫـﺬه اﻟﻈـﺎﻫﺮة ﺑﺎﺳـﻢ ﻧـﻮاة ا ﺠـﺮة اﻟﻨﺸ ـﻄ ﺔ وﻳﻤﻜ ـﻦ أن ﻳﺘﺠ ـﺎوز ﺳ ـﻄﻮﻋﻬﺎ اﻟﻈﺎﻫﺮي أﺣﻴﺎﻧ ﺎً ﻛﻞ ﺿﻮء اﻟﻨﺠﻮم ﰲ ا . ﺠـﺮة ــ وﻣﻦ ا ﺜ ﻟﻼﻫﺘﻤﺎ م أﻧﻪ ﻳُﻌﺘﻘﺪ أن ﺟﺰء اً ﻣـﻦ اﻟﻐﺎز اﻟﺬي ﻳﺴـﻘﻂ ﺑﺎﺗﺠـﺎه اﻟﺜﻘـﺐ اﻷﺳـﻮد اﻟﺘــ ) ﺪﻓﻖ اﻟﱰاﻛﻤـﻲ ( ﻗـﺪ ﺗــﻢ ﻗﺬﻓـﻪ اً ﺑﻌﻴـﺪ ﺑﻮاﺳﻄﺔ اﻟﻄﺎﻗﺔ اﻟﻬ ﺎﺋﻠﺔ ﻟﻬﺬه اﻟﻨﻮاة ا ﺠﺮﻳـﺔ اﻟﻨﺸﻄﺔ ﻣﻤﺎ ﻳﺆدي إﱃ اﻟﺘﺪﻓﻘﺎت إﱃ اﻟﺨﺎرج . وﻗـﺪ ﻗـﺪﻣﺖ ﻛـﻞ ﻣـﻦ اﻟﺪراﺳـﺎت اﻟﻨﻈﺮﻳـﺔ واﻟﺮﺻﺪﻳﺔ رؤى ﺗﻔ ﺼﻴﻠﻴﺔ ﺣﻮل آﻟﻴﺎت ﺗـﺮاﻛﻢ اﻟﻐـﺎز ﺑـ اً ﺪء ﻣـﻦ ﻣﻘﻴـﺎس 100,000 ﺳـﻨﺔ ﺿﻮﺋﻴﺔ ﻟﻠﻤﺠﺮات وﺻﻮﻻ إﱃ ﻣﻘﻴـﺎس ﺑﻀـﻊ ﻣﺌﺎت ﻣﻦ اﻟ ﺴﻨ اﻟﻀﻮﺋﻴﺔ ﰲ ا ﺮﻛﺰوﻣﻊ ذﻟﻚ ﻓﺈن ﺗﺮاﻛﻢ اﻟﻐﺎز داﺧﻞ ﻣﻨﻄﻘﺔ أﺻﻐﺮ ﺑﻜﺜـ ــ - ﻳﺮ ﻳﻨﺎ ﻓﺒﺮﺍﻳﺮ 2 0 2 4