Free Astronomy Magazine September-October 2023 ARABIC VERSION

35 chance mergers of neutron stars, as- tronomers have con- cluded that this GRB came instead from the collision of stars or stellar remnants in the jam-packed envi- ronment surrounding a supermassive black hole at the core of an ancient galaxy. [Inter- national Gemini Ob- servatory/NOIRLab/ NSF/AURA/M. Gar- lick/M. Zamani] Swift Observatory detected a bright flash of gamma rays that lasted for a little more than one minute. Any GRB lasting more than two seconds is considered “long.” Such bursts typically come from the supernova death of stars at least 10 times the mass of our Sun — but not always. The researchers then used Gemini South to make long-term observa- tions of the GRB’s fading afterglow to learn more about its origins. The observations allowed the as- tronomers to pinpoint the location of the GRB to a region less than 100 light-years from the nucleus of an ancient galaxy, which placed it very near the galaxy’s supermassive black hole. The researchers also found no evidence of a corresponding super- nova, which would leave its imprint studied outh. up ob- us that eing a collaps- st was used by f two bjects,” By pin- ocation r of a previously identified ancient galaxy, we had the first tantaliz- ing evidence of a new pathway for stars to meet their demise.” In normal galactic environ- ments, the production of long GRBs from colliding stellar remnants such as neutron stars and black holes is thought to be vanishingly rare. The cores of ancient galaxies, how- ever, are anything but normal and there may be a million or more stars crammed into a region just a few light-years across. Such extreme population density may be great enough that occasional stellar colli- sions can occur, especially under the titanic gravitational influence of a supermassive black hole, which would perturb the motions of stars and send them careening in random directions. Eventually, these way- ward stars would intersect and merge, triggering a titanic explosion that could be observed from vast cosmic distances. It is possible that such events occur routinely in simi- larly crowded regions across the Uni- verse but have gone unnoticed until this point. A possible reason for their obscurity is that galactic centers are brimming with dust and gas, which could ob- scure both the initial flash of the GRB and the resulting afterglow. This particular GRB, identified as GRB 191019A, may be a rare excep- tion, allowing astronomers to detect the burst and study its after effects. The researchers would like to dis- cover more of these events. Their hope is to match a GRB detection with a corresponding gravitational- wave detection, which would reveal more about their true nature and confirm their origins, even in the murkiest of environments. The Vera C. Rubin Observatory, when it comes online in 2025, will be invaluable in this kind of research. “Studying gamma-ray bursts like these is a great example of how the field is really advanced by many facilities working together, from the detection of the GRB, to the dis- coveries of afterglows and distances with telescopes like Gemini, through to detailed dissection of events with observations across the electromagnetic spectrum,” said Levan. “These observations add to Gemini’s rich heritage developing our understanding of stellar evolu- tion,” says Martin Still, NSF’s pro- gram director for the International Gemini Observatory. “The time sen- sitive observations are a testament to Gemini’s nimble operations and sensitivity to distant, dynamic events across the Universe.”     ـــــــــﻮن ﻋﻠﻤـــــــــﺎء اﻟﻔﻠـــــــــﻚ رﻤـــــــــﺎ ﻳ اﻟــﺬﻳﻦ ﺪرﺳـــﻮن ًـــﺎ اﻧﻔﺠـــﺎرًا ﻗﻮ ﻷﺷـــﻌﺔ ﺟﺎﻣـــﺎ (GRB) ﻣـــﻊ ــــــــــــﻮزاء اﻟــــــــــــﺪوﻟﻲ، ﻣﺮﺻــــــــــــﺪ ا ــﺪﻳﺮﻩ ﻣﺨﺘــ اﻟـﺬ ﻧــﻮﻳﺮﻻب اﻟﺘــــــــﺎﺑﻊ ﻟﻤﺆﺳﺴــــــــﺔ اﻟﻌﻠــــــــﻮم ــــــــــــــﺔ ــــــــــــــﺔ اﻷﻣﺮ ﻜ اﻟﻮﻃﻨ ﻗــــــــــــــﺪ رﺻﺪوا ﻃﺮ ﻘﺔ ﻟﻢ ﺴﺒﻖ ﻟﻬـﺎ ـــــﻢ ﻣﺜﻴـــــﻞ ﻟﺘــــــﺪﻣ ﻧ . وﺧﻼﻓًــــــﺎ ﻟﻤﻌﻈـــــــﻢ اﻧﻔﺠـــــــﺎرات أﺷـــــــﻌﺔ ﻏﺎﻣـــﺎ ﺗﻨـــﺘﺞ ﻋـــﻦ اﻧﻔﺠـــﺎر اﻟـــ ﻧﺠــــــــــﻮمﺿــــــــــ ﻤﺔ أو اﺣﺘﻤــــــــــﺎل اﻧﺪﻣﺎج ﻧﺠﻮم ﻧﻴﻮﺗﺮوﻧ ﺔ ﻓﻘـﺪ اﺳـــــــــــﺘﻨﺘﺞ ﻋﻠﻤـــــــــــﺎء اﻟﻔﻠـــــــــــﻚ أن اﻧﻔﺠـﺎرات أﺷـﻌﺔ ﻏﺎﻣـﺎ ﻫــﺬﻩ ـــــــﺪﻻً ﻣـــــــﻦ ذﻟـــــــﻚ ﻣـــــــﻦ ﺟـــــــﺎءت ــــــــــــﺎ اﺻـــــــــــﻄﺪام ﻧﺠــــــــــــﻮم أو ﻘﺎ ﻧ ﻤ ﺔ ﻓﻲ اﻟﺒﻴﺌـﺔ اﻟﻤﺰد ﻤـﺔ اﻟﻤﺤ ﻄﺔ ﺑﺠﺮم ﻓﺎﺋﻖ اﻟﻜﺘﻠـﺔ . ﺛﻘـﺐ أﺳــﻮد ﻓــﻲﻗﻠــﺐ ﻣﺠــﺮة . ﻗﺪ ﻤﺔ ﺷﻮﻫﺪت اﻟﺘﻠﻤﻴﺤﺎت اﻷوﱃ إﱃ ﺣـﺪوث ﻣﺜـﻞ ﻫـﺬا اﻟﺤـﺪث ﰲ 19 أﻛﺘـﻮﺑﺮ 2019 ﻋﻨـﺪﻣﺎ اﻛﺘﺸﻒ ﻣﺮﺻﺪ ﻧﻴﻞ ﺟ ﻟﻴﺰ ﺳﻮﻳﻔﺖ اﻟﺘـﺎﺑﻊ ﻟ ﻮﻛﺎﻟﺔ ﻧﺎﺳﺎ وﻣﻴﻀًﺎ ﺎً ﺳﺎﻃﻌ ﻣﻦ أﺷﻌﺔ ﺎﻣﺎ ﻏ اﺳﺘﻤﺮ ﻷﻛﺜﺮ ﻣﻦ دﻗﻴﻘﺔ واﺣـﺪة ﺑﻘﻠﻴـﻞ أي . اﻧﻔﺠﺎر ﻷﺷـﻌﺔ ﻏﺎﻣـﺎ ﻳﺴـﺘﻤﺮ ﻷﻛﺜـﺮ ﻣـﻦ ﺛﺎﻧﻴﺘ ﻳﻌﺘﱪ " ". ﻃـﻮﻳﻼً ﺗـﺄﺗﻲ ﻣﺜـﻞ ﻫـﺬه اﻻﻧﻔﺠـﺎرات ﻋـﺎدة ﻣـﻦ ﻣـﻮت ا ﺴـﺘﻌﺮات اﻷﻋﻈﻢ ﻟﻨﺠﻮم ﺗﺒﻠﻎ ﻛﺘﻠﺘﻬﺎ 10 أﺿﻌﺎف ﻛﺘﻠﺔ اﻟﺸـﻤﺲ ﻋـﲆ اﻷﻗـﻞ وﻟﻜـﻦ ﻟـﻴﺲ داﺋﻤًـﺎ . اﺳﺘﺨﺪم اﻟﺒﺎﺣﺜﻮن ﺑﻌﺪ ذﻟﻚ ﺟﻴﻤﻴﻨﻲ ﺳﺎوث ﻹﺟﺮاء ﻣﻼﺣﻈﺎت ﻃﻮﻳﻠﺔ ا ﺪى ﻟﺘﻼﳾﺷﻔﻖ اﻧﻔﺠﺎرات اﺷﻌﺔ ﻏﺎﻣﺎ ﻌﺮﻓـﺔ ا ﺰﻳـﺪ ﻋـﻦ أﺻﻮﻟﻪ . ﺳـﻤﺤﺖ اﻷرﺻـﺎد ﻟﻌﻠﻤـﺎء اﻟﻔﻠـﻚ ﺑﺘﺤﺪﻳﺪ ﻣﻮﻗـﻊ اﻧﻔﺠـﺎرات أﺷـﻌﺔ ﻏﺎﻣـﺎ ﰲ ﻣﻨﻄﻘﺔ ﺗﺒﻌﺪ أﻗﻞ ﻣﻦ 100 ﺳﻨﺔ ﺿﻮﺋﻴﺔ ﻋﻦ ﻋﻦ ﻧـﻮاة ﻣﺠـﺮة ﻗﺪﻳﻤـﺔ ﻣﻤﺎ وﺿﻌﻬﺎ ﻗﺮب اﻟﺜﻘﺐ اﻷﺳﻮد اﻟﻬﺎﺋـﻞ ﰲ ا ﺠـﺮة وﻟﻢ ﻳﺠﺪ اﻟﺒﺎﺣﺜﻮن أﻳ ﺎ ﻀـ أي دﻟﻴــﻞ ﻋــﲆ وﺟــﻮد ﻣﺴـﺘﻌﺮ أﻋﻈـﻢ ﻣﻤﺎﺛ ـﻞ واﻟﺬي ﻣﻦ ﺷﺄﻧﻪ أن ﻳـﱰك ﺑﺼﻤﺎﺗﻪ ﻋﲆ اﻟﻀﻮء اﻟﺬي درﺳﻪ ﺗﻠﺴﻜﻮب ﺟﻴﻤﻴﻨﻲ . ﺳـﺎوث ﻗـﺎل ﻟﻴﻔـﺎن ": أﺧﱪﺗﻨﺎ أرﺻﺎدﻧﺎ اﻟﻼﺣﻘﺔ أﻧﻪ ﺑـﺪﻻً ﻣـﻦ أن ﻳﻜـﻮن ﺎً ﻤﻧﺠ ﺎً ﺿﺨﻤ ﻳﻨﻬﺎر ﻛـﺎن اﻻﻧﻔﺠـﺎر ﻋـﲆ اﻷرﺟـﺢ ﻧﺎﺗﺠًﺎ ﻋـﻦ اﻧـﺪﻣﺎج ﺟﺴـﻤ وﻣـﻦ ﺧـﻼل ﰲﺎ ﻤ ـ ﻣﻮﻗﻌﻬ ﻣﺮﻛ ـﺰ ﻣﺠــﺮة ﻗﺪﻳﻤ ـﺔ ﺗــﻢ ﺗﺤﺪﻳﺪﻫﺎ ﻣﺴﺒﻘﺎً ﺣﺼﻠﻨﺎ ﻋﲆ أول دﻟﻴﻞ ﻋـﲆ ﻣﺴﺎر ﺟﺪﻳﺪ ﻟﻠﻨﺠﻮم ﻮاﺟﻬﺔ زواﻟﻬﺎ . ﰲ اﻟﺒﻴﺌﺎت ا ﺠﺮﻳﺔ اﻟﻌﺎدﻳﺔ ﻳُﻌﺘﻘﺪ أن إﻧﺘـﺎج دﻓﻘﺎت أﺷـﻌﺔ ﻏﺎﻣـﺎ اﻟﻄﻮﻳﻠـﺔ ﻣـﻦ ﺑﻘﺎﻳـﺎ اﻟﻨﺠﻮم ا ﺘﺼﺎدﻣﺔ ﻣﺜﻞ اﻟﻨﺠﻮم اﻟﻨﻴﻮﺗﺮوﻧﻴـﺔ واﻟﺜﻘﻮب ا ﻟﺴﻮداء أﻣﺮ ﻧﺎدر اﻟﺤـﺪوث وﻣـﻊ ذﻟﻚ ﻓﺈن ﻣﺮاﻛﺰ ا ﺠـﺮات اﻟﻘﺪﻳﻤـﺔ ﻟﻴﺴـﺖ ﻋﺎدﻳﺔ ﻋﲆ اﻹﻃﻼق وﻗﺪ ﻳﻜﻮن ﻫﻨﺎك ﻣﻠﻴﻮن ﻧﺠﻢ أو أﻛﺜﺮ ﻣﺤﺸﻮرة ﰲ ﻣﻨﻄﻘﺔ ﻻ ﻳﺘﺠﺎوز ﻋﺮﺿﻬﺎ ﺑﻀﻊ ﺳﻨﻮات ﺿـﻮﺋﻴﺔ . ﻗـﺪ ﺗﻜـﻮن ﻣﺜﻞ ﻫﺬه اﻟﻜﺜﺎﻓﺔ اﻟﺴﻜﺎﻧﻴﺔ اﻟﺸﺪﻳﺪة ﻛﺒـ ة ﺑﻤـﺎ ﻳﻜﻔـﻲ ﻟﺤــﺪوث ﺗﺼـﺎدﻣﺎت ﻧﺠﻤﻴــﺔ ﻋﺮﺿــﻴﺔ ﺧﺎﺻـﺔ ﺗﺤـﺖ ﺗ ـﺄﺛ اﻟﺠﺎذﺑﻴــﺔ اﻟﻌﻤﻼﻗﺔ ﻟﺜﻘﺐ أﺳﻮد ﻓﺎﺋﻖ اﻟﻜﺘﻠﺔ ﻣﻤـﺎ ﻗـﺪ ﻳﺰﻋﺞ ﺣﺮﻛﺎت اﻟﻨﺠﻮم وﻳﺪﻓﻌﻬﺎ إﱃ اﻻﻧﺤﻨﺎء ﰲ اﺗﺠﺎﻫﺎت ﻋﺸـﻮاﺋﻴﺔ وﰲ ﻧﻬﺎﻳـﺔ ا ﻄـﺎف ﺳﺘﺘﻘﺎﻃﻊ ﻫﺬه اﻟﻨﺠﻮم اﻟﻀﺎﻟﺔ وﺗﻨﺪﻣﺞ ﻣﻤﺎ ﻳﺆدي إﱃ اﻧﻔﺠﺎر ﻫﺎﺋﻞ ﻳﻤﻜـﻦ رﺻـﺪه ﻣـﻦ ﻣﺴﺎﻓﺎت ﻛﻮﻧﻴـﺔ ﺷﺎﺳـﻌﺔ . أﺣـﺪ اﻷﺳـﺒﺎب ا ﺤﺘﻤﻠﺔ ﻟﻐﻤﻮﺿﻬﺎ ﻫـﻮ أن ﻣﺮاﻛـﺰ ا ﺠـﺮة ﻣﻠﻴﺌﺔ ﺑﺎﻟﻐﺒﺎر واﻟﻐﺎز، ﻣ ﻤﺎ ﻗﺪ ﻳﺤﺠـﺐ ﻛـﻼً ﻣﻦ اﻟﻮﻣﻴﺾ اﻷوﱄ ﻷ ﺷـﻌﺔ ﻏﺎﻣـﺎ واﻟﺸـﻔﻖ اﻟﻨﺎﺗﺞ ﻋﻨﻪ ﻳﻗﺪ . ا ﻜﻮن ﻫﺬ اﻻﻧﻔﺠﺎر ﻷﺷـﻌﺔ ﺗﻢ ﺗﺴﻤﻴﺘﻪ GRB 191019A اﺳﺘﺜﻨﺎءً ﻧـﺎد ر ﻣﻤ ـﺎ ﻳﺴ ـﻤﺢ ﻟﻌﻠﻤ ـﺎء اﻟﻔﻠ ـﻚ ﺑﺎﻛﺘﺸ ـﺎف اﻻﻧﻔﺠﺎر ودراﺳـﺔ آﺛـﺎره اﻟﻼﺣﻘـﺔ . ﻳﺮﻏـﺐ اﻟﺒﺎﺣﺜﻮن اﻛﺘﺸﺎف ا ﺰﻳﺪ ﻣﻦ ﻫﺬه اﻷﺣـﺪاث و ﻣﻄﺎﺑﻘﺔ اﻛﺘﺸﺎف اﻧﻔﺠﺎرات اﺷـﻌﺔ ﻏﺎﻣـﺎ ﻣـﻊ اﻛﺘﺸــﺎف ﻣﻮﺟـﺎت اﻟﺠﺎذﺑﻴـﺔ ﺑ ﻬـﺪف اﻟﻜﺸﻒ ﻣﻦ ﻣﺰﻳﺪ ﻋﻦ ﻃﺒﻴﻌﺘﻬـﺎ اﻟﺤﻘﻴﻘﻴـﺔ و أﺻﻮﻟﻬﺎ ﺣﺘﻰ ﰲ أﻛﺜﺮ اﻟﺒﻴﺌﺎت ﻏﻤﻮ ان .ﺎً ﺿـ ﻣﺮﺻﺪ ﻓ ا ﳼ روﺑ ﻋﻨﺪﻣﺎ ﻳﺼﺒﺢ ﺟﺎﻫﺰ اً ﻟﻼﺳﺘﺨﺪام ﰲ ﻋﺎم 2025 ﺳﻴﻜﻮن ذا ﻗﻴﻤﺔ ﻻ ﺗﻘﺪر ﺑﺜﻤﻦ ﰲ ﻫﺬا اﻟﻨﻮع ﻣﻦ اﻷﺑﺤﺎث . ﻗـﺎل ﻟﻴﻔﺎن :" إن دراﺳﺔ اﻧﻔﺠﺎرات أﺷـﻌﺔ ﺟﺎﻣـﺎ ﻣﺜﻞ ﻫﺬه ﻫﻲ ﻣﺜﺎل راﺋﻊ ﻋﲆ ﻛﻴﻔﻴـﺔ ﺗﻘـﺪم ﻫﺬا ا ﺠﺎل ﺑﺎﻟﻔﻌﻞ ﻣﻦ ﺧـﻼل اﻟﻌﺪﻳـﺪ ﻣـﻦ ا ﻨﺸﺎت اﻟﺘﻲ ﺗﻌﻤﻞ ﻣﻌًﺎ اً ﺑﺪء ﻣﻦ اﻛﺘﺸـﺎف اﻧﻔﺠﺎرات أﺷﻌﺔ ﻏﺎﻣﺎ إﱃ اﻛﺘﺸﺎﻓ ﺎت اﻟﺸﻔﻖ وا ﺴﺎﻓﺎت ﺑﺎﺳـﺘﺨﺪام اﻟﺘﻠﺴـﻜﻮﺑﺎت ﻣﺜـﻞ ﺟﻴﻤﻴﻨﻲ وﺻـﻮﻻً إﱃ اﻟﺘـ ـ ﴩﻳﺢ اﻟﺘﻔﺼـﻴﲇ ﻟﻸﺣــﺪاث ﻣــﻊ اﻷرﺻــﺎد ﻋــﱪ اﻟﻄﻴــﻒ اﻟﻜﻬﺮوﻣﻐﻨﺎﻃﻴﴘ، ﻳﻘﻮل ﻣﺎرﺗﻦ ﺳﺘﻴﻞ ﻣﺪﻳﺮ ﺑﺮﻧﺎﻣﺞ ﻣﺆﺳﺴﺔ اﻟﻌﻠﻮم اﻟﻮﻃﻨﻴﺔ ﰲ ﻣﺮﺻـﺪ ﺟﻴﻤﻴﻨﻲ اﻟﺪوﱄ " : ﺗﻀﻴﻒ ﻫـﺬه اﻷرﺻـﺎد إﱃ ﻓﻬﻤﻨﺎ ﻟﺘﻄﻮر اﻟﻨﺠـﻮم و ﻫـﻲ ﺷـﻬﺎدة ﻋـﲆ ت ﻋﻤﻠﻴﺎ ﻣﺮﺻﺪ ﺟﻴﻤﻴﻨـﻲ اﻟﺬﻛﻴـﺔ ﻟﻸﺣـﺪاث اﻟﺪﻳﻨﺎﻣﻴﻜﻴﺔ اﻟﺒﻌﻴﺪة ﻋﱪ اﻟﻜﻮن ." ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 5 - ﺳﺒﺘﻤﺒﺮ ﺃﻛﺘﻮﺑﺮ 2 0 2 3 ﻳﻮﺿﺢ ﻫﺬا اﻟﻔ ﺪﻳﻮ ﻛ ﻒ أن ﻋﻠﻤﺎء اﻟﻔﻠﻚ اﻟﺬﻳﻦ ﺪرﺳﻮن اﻧﻔﺠﺎرأﺷﻌﺔ ﺔﻘﻮ اﻟ ﺎﻣﺎ ﻏ ﻗﺪ رﺻﺪوا ﻃﺮ ﻘﺔ ﻟﻢ ﺴﺒﻖ ﻟﻬﺎ ﻣﺜﻴﻞ ﻟﺘﺪﻣ ﻧ ﻢ . [In- ternational Gemini Observatory/NOIRLab/NSF/AURA, M. Garlick, M. Zamani, K. O Chul, ESO/L. Calçada, NASA’s Goddard Space Flight Center/CI Lab, N. Bartmann]. [Inter- national Gemini Ob- s rvat ry/NOIRLab/ NSF/AURA/M. Gar- lick/M. Zamani]