Free Astronomy Magazine May-June 2023 ARABIC VERSION

To trace the history of migration in M31, the team turned to DESI. DESI was constructed to map tens of mil- lions of galaxies and quasars in the nearby Universe in order to measure the effect of dark energy on the ex- pansion of the Universe. It is the most powerful multi-object survey spectrograph in the world, and is ca- pable of measuring the spectra of more than 100,000 galaxies a night. DESI’s world-class capabilities can also be put to use closer to home, however, and the instrument was crucial to the team’s survey of M31. “This science could not have been done at any other facility in the world. DESI’s amazing efficiency, throughput, and field of view make it the best system in the world to carry out a survey of the stars in the Andromeda Galaxy,” said Dey. “In only a few hours of observing time, DESI was able to surpass more than a decade of spectroscopy with much larger telescopes.” Even though the Mayall Telescope was completed 50 years ago (it achieved first light in 1973), it re- mains a world-class astronomical fa- cility thanks to continued upgrades and state-of-the-art instrumenta- tion. “Fifty years sounds like a long time, and naïvely one might think that’s the natural lifetime of a facil- ity,” said co-author Joan R. Najita, also at NOIRLab. “But with renewal and reuse, a venerable telescope like the Mayall can continue to make amazing discoveries despite being relatively small by today’s stan- dards.” The research was carried out in col- laboration with two Harvard Univer- sity undergraduates, Gabriel Maxemin and Joshua Josephy-Zack, who connected with the project through the Radcliffe Institute for Advanced Study. Najita was a Rad- cliffe Fellow from 2021 to 2022. The team now plans to use the un- paralleled capabilities of DESI and the Mayall Telescope to explore more of M31’s outlying stars, with the aim of revealing its structure and immigration history in unprece- dented detail. “It’s amazing that we can look out at the sky and read billions of years of another galaxy’s history as writ- ten in the motions of its stars — each star tells part of the story,” concluded Najita. “Our initial obser- vations exceeded our wildest expec- tations and we are now hoping to conduct a survey of the entire M31 halo with DESI. Who knows what new discoveries await!”  ﻟﺘﺘﺒﻊ ﺗﺎرﻳﺦ اﻟﻬﺠﺮة ﰲ ﻣﺠﺮة ﻣﻴﺴﻴﻴﻪ ٣١ ﻟﺠﺄ اﻟﻔﺮﻳ ـﻖ إﱃ أداة اﻟﺘﺤﻠﻴ ـﻞ اﻟﻄﻴﻔ ـﻲ ﻟﻠﻄﺎﻗ ـﺔ ا ﻈﻠﻤﺔ DESI) ( . ﻟﻘﺪ ﺗـﻢ ﺻـﻨﺎﻋﺔ ) (DESI ﻟﺮﺳﻢ ﺧﺮاﺋﻂ ﻟﻌﴩات ا ﻼﻳ ﻣـﻦ ا ﺠـﺮات واﻟﻜﻮازارات ﰲ اﻟﻜﻮن اﻟﻘﺮﻳﺐ ﻣﻦ أﺟﻞ ﻗﻴﺎس ﺗﺄﺛ اﻟﻄﺎﻗﺔ ا ﻈﻠﻤﺔ ﻋﲆ ﺗﻤﺪد اﻟﻜﻮن . إﻧﻪ أﻗﻮى ﻣﻄﻴﺎف ﻣﺴﺢ ﻣﺘﻌـﺪد اﻷﺟﺴـﺎم ﰲ اﻟﻌﺎﻟﻢ وﻫﻮ ﻗﺎدر ﻋﲆ ﻗﻴﺎس أﻃﻴﺎف أﻛﺜﺮ ﻣﻦ ١٠٠,٠٠٠ ﻣﺠــﺮة . ﰲ اﻟﻠﻴﻠــﺔ ﻳﻤﻜــﻦ أﻳﻀًــﺎ اﺳـﺘﺨﺪام إﻣﻜﺎﻧـﺎت ) DESI ( ذات ا ﺴـﺘﻮى اﻟﻌـﺎ ﻲ ﺑـﺎﻟﻘﺮب ﻣـﻦ ا ﻨـﺰل وﻛﺎﻧـﺖ اﻷداة ﺣﺎﺳﻤﺔ ﰲ ﻣﺴﺢ اﻟﻔﺮﻳﻖ ﺠﺮة ﻣﻴﺴـﻴﻴﻪ ٣١ . ﻫﺬا اﻟﻌﻠﻢ ﻻ ﻳﻤﻜﻦ أن ﻳﺘﻢ ﰲ أي ﻣﻨﺸﺄة أﺧﺮى . ﰲ اﻟﻌـﺎﻟﻢ إن اﻟﻜﻔـﺎءة ا ﺬﻫﻠـﺔ واﻹﻧﺘﺎﺟﻴ ـﺔ وﻣﺠﺎل اﻟﺮؤﻳﺔ ) ﻄﻴﺎف DESI ( ﺗﺠﻌﻠﻪ أﻓﻀﻞ ﻧﻈﺎم ﰲ اﻟﻌﺎﻟﻢ ﻹﺟﺮاء ﻣﺴﺢ ﻟﻠﻨﺠﻮم ﰲ ﻣﺠﺮة أﻧﺪروﻣﻴﺪا " ﻗـﺎل داي " . ﰲ ﻏﻀـﻮن ﺳـﺎﻋﺎت ﻗﻠﻴﻠﺔ ﻓﻘﻂ ﻣﻦ وﻗﺖ ا ﺮ اﻗﺒﺔ ، ﺗﻤﻜﻦ ﻣﻄﻴﺎف (DESI) ﻣﻦ ﺗﺠﺎوز ﻧﺘﺎﺋﺞ أﻛﺜﺮ ﻣﻦ ﻋﻘﺪ ﻣـﻦ اﻟﺘﺤﻠﻴﻞ اﻟﻄﻴﻔﻲ ﺑﺎﺳﺘﺨﺪام ﺗﻠﺴﻜﻮﺑﺎت أﻛـﱪ ﺑ. ﺑﻜﺜ ﺎﻟﺮﻏﻢ ﻣـﻦ اﻛﺘﻤـﺎل ﺑﻨـﺎء ﺗﻠﺴـﻜﻮب ﻣﺎﻳﻮل ﻗﺒﻞ ٥٠ ﺄول ﺑـ ﻗﺎم) ﻋﺎﻣًﺎ رﺻـﺪ ﻟـﻪ ﰲ م ﻋﺎ ١٩٧٣ ( إﻻ أﻧﻪ ﻳﻈﻞ ﻣﻨﺸﺄة ﻓﻠﻜﻴـﺔ ﻋـﲆ ﻣﺴﺘﻮى ﻋـﺎ ﻲ ﺑﻔﻀـﻞ اﻟﱰﻗﻴـﺎت ا ﺴـﺘﻤﺮة وأﺣﺪث اﻷﺟﻬﺰة . ﻗﺎل ا ﺆﻟﻒ ا ﺸﺎرك ﺟﻮان آر ﻧﺎﺟﻴﺘﺎ ، اﻟﺬي ﻳﻌﻤﻞ أﻳﻀًﺎ ﰲ ﻣﺨﺘﱪ ﻧـﻮﻳﺮﻻب : " ﺧﻤﺴﻮن ﻋﺎﻣًﺎ ﺗﺒﺪو وﻛﺄﻧﻬﺎ ﻓﱰة ﻃﻮﻳﻠﺔ وﻗﺪ ﻳﻈﻦ ا ﺮء ﺑﺴﺬاﺟﺔ أن ﻫﺬا ﻫﻮ اﻟﻌﻤﺮ اﻟﻄﺒﻴﻌﻲ ﻟﻠﻤﻨﺸــﺄة " وﻟﻜــﻦ ﻣــﻊ اﻟ ﺘﺠﺪﻳــﺪ وإﻋــﺎدة اﻻﺳـﺘﺨﺪام ﻳﻤﻜ ـﻦ أن ﻳﺴـﺘﻤﺮ اﻟﺘﻠﺴ ـﻜﻮب اﻟﺠﻠﻴـﻞ ﻣﺜ ـﻞ ﺗﻠﺴـﻜﻮب ﻣﺎﻳ ـﺎل ﰲ ﺗﺤﻘﻴ ـﻖ اﻛﺘﺸﺎﻓﺎت ﻣﺬﻫﻠﺔ ﻋﲆ اﻟﺮﻏﻢ ﻣﻦ ﻛﻮﻧﻪ ﺻﻐ ًا ﻧﺴﺒﻴًﺎ وﻓﻘًﺎ ﻌﺎﻳ اﻟﻴﻮم . ﺗﻢ إﺟـﺮاء اﻟﺒﺤـﺚ ﺑﺎﻟﺘﻌﺎون ﻣﻊ اﺛﻨ ﻣﻦ اﻟﻄﻼب اﻟﺠـﺎﻣﻌﻴ ﰲ ﺟﺎﻣﻌ ـﺔ ﻫﺎرﻓــﺎرد ، ﻏﺎﺑﺮ ﻳﻴــﻞ ﻣﺎﻛﺴــﻴﻤ وﺟﻮﺷــﻮا ﺟــﻮزﻳﻔﻲ زاك اﻟــ ﺬﻳﻦ ارﺗﺒﻄــ ﺎ ﺑﺎ ﴩوع ﻣﻦ ﺧﻼل ﻣﻌﻬﺪ رادﻛﻠﻴﻒ ﻟﻠﺪراﺳﺎت ا ﺘﻘﺪﻣﺔ . ﻧﺠﻴﺘﺎ ﻛﺎﻧﺖ زﻣﻴﻠـﺔ رادﻛﻠﻴـﻒ ﻣـﻦ ٢٠٢١ إﱃ ٢٠٢٢ . ﻳﺨﻄ ـــﻂ اﻟﻔﺮﻳ ـــﻖ اﻵن ﻻﺳﺘﺨﺪام ﻻﺳـــﺘﺨﺪام ﻗـــﺪرات ﻣﻄﻴـــﺎف ) DESI ( و ﺗﻠﺴـﻜﻮب ﻣﺎﻳـﺎل ﻻﺳﺘﻜﺸـﺎف ا ﺰﻳـﺪ ﻣـﻦ اﻟﻨﺠﻮم اﻟﺒﻌﻴـﺪة ﺠـﺮة ﻣﻴﺴـﻴﻴﻪ ٣١ ﺑﻬـﺪف اﻟﻜﺸﻒ ﻋﻦ ﻫﻴﻜﻠﻬﺎ وﺗﺎرﻳﺦ اﻟﻬ ﺠﺮة ﺑﺘﻔﺎﺻﻴﻞ ﻏ ﻣﺴﺒﻮﻗﺔ . واﺧﺘﺘﻤﺖ ﻧﺠﻴﺘﺎ ﻗﺎﺋﻠـﺔ " : إﻧـﻪ ﻷﻣﺮ ﻣﺪﻫﺶ أن ﻧﺘﻤﻜﻦ ﻣﻦ اﻟﻨﻈﺮ إﱃ اﻟﺴﻤﺎء وﻗﺮاءة ﻣﻠﻴﺎرات اﻟﺴﻨ ﻣـﻦ ﺗـﺎرﻳﺦ ﻣﺠـﺮة أﺧﺮى ﰲ ﺣﺮﻛﺎت ﻧﺠﻮﻣﻬﺎ ﻓﻜـﻞ ﻧﺠـﻢ ﻳـﺮوي ﺟﺰءًا ﻣﻦ اﻟﻘﺼـﺔ . ﻟﻘـﺪ ﺗﺠـﺎوزت أرﺻـﺎدﻧﺎ اﻷوﻟﻴﺔ ﺗﻮﻗﻌﺎﺗﻨﺎ وﻧﺄﻣﻞ اﻵن إﺟﺮاء ﻣﺴﺢ ﻟﻬﺎﻟﺔ ﻣﻴﺴﻴﻴﻪ ٣١ ﺑﺎ ﻟﻜﺎﻣﻞ ﺑﺎﺳﺘﺨﺪام ) DESI ( ﻣﻦ ﻳﺪري ﻣﺎذا ﺗﻨﺘﻈﺮ اﻻﻛﺘﺸﺎﻓﺎت اﻟﺠﺪﻳﺪة " ! ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ ٣٥ - ﻣﺎﻳﻮ ﻳﻮﻧﻴﻮ 2023 اﻛﺘﺸﻒ ﺎﺣﺜﻮن ﻘ ﺎدة ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻓﻲﻣﺨﺘ ﻧﻮﻳﺮﻻب اﻟﺘﺎﺑﻊ ﻟﻤﻮﺳﺔ اﻟﻌﻠﻮم اﻟﻮﻃﻨ ﺔ اﻻﻣﺮ ﻜ ﺔ دﻟ ﻼً ﺟﺪ ﺪًا واﺿﺤﺎ ﻋﻠـﻰ اﻟﻬﺠـﺮة اﻟـ ـ ﻤﺎﻋ ﺔ ﻟﻠﻨﺠـﻮم إﻟـﻰﻣﺠـﺮة اﻟﻤـﺮأة اﻟﻤﺴﻠﺴـﻠﺔ . اﺳـﺘﺨﺪم اﻟﻔﺮ ـﻖ ـﻮﻻس ﻳـﻮ ﻣــﺎﻳﻮل أداة اﻟﺘﺤﻠﻴـﻞ اﻟﻄ ﻔـﻲ ﻟﻠﻄﺎﻗـﺔ اﻟﻤﻈﻠﻤـﺔ اﻟﺘﺎ ﻌـﺔ ﻟـﻮزارة اﻟﻄﺎﻗـﺔ ﻋﻠـﻰ ﺗﻠﺴـ ﻮب ﻧﻴ اﻟـﺬ ﻳ ﻠــﻎ ٤ وﻫــﻮ ﺑﺮ ــﺎﻣﺞ ــﻚ اﻟــﻮﻃ ـﺖ ﺑ أﻣﺘــﺎرﻓـﻲﻣﺮﺻـﺪ ﻛ ـﻞ اﻟﻤﻌﻘــﺪة ﻓـﻲ ﻟﻠﻜﺸـﻒﻋــﻦ اﻟﻬ ﺎ ﻫـﺬﻩ اﻟﻤﺠـﺮة ﺘﻔﺎﺻـﻴﻞ ووﺿـﻮح ﻏـ ﻣﺴـﺒﻮﻗ . ـﻞ ﻧﻘﻄـﺔ ﻓـﻲﻫـﺬﻩ اﻟﺼـﻮرة ﻧ ﺗﻤﺜـﻞ ًـﺎ ﻓـﻲ ﻤًـﺎ ﻓﺮد ﻣﺠـــﺮة اﻟﻤـــﺮأة اﻟﻤﺴﻠﺴــــﻠﺔ ، ﻣـــﻊﺣﺮﻛــــﺔ اﻟـــﻨ ﻢ ) ﺎﻟﻨﺴــــ ﺔ إﻟـــﻰ اﻟﻤﺠــــﺮة ( ــــﺎﻷﻟﻮان ﻣـــﻦ اﻟﻠــــﻮن ﻣﺸـــﻔﺮة اﻷزرق ) ﺘﺤﺮك ﻧﺤﻮﻧﺎ ( إﻟﻰ اﻷ ﻤﺮ ) ﻳ ﺘﻌﺪ ﻋﻨﺎ .(