Free Astronomy Magazine March-April 2023 ARABIC VERSION

T 19 he Milky Way Galaxy contains hundreds of billions of stars, glimmering star-forming re- gions, and towering dark clouds of dust and gas. Imaging and cataloging these objects for study is a herculean task, but a newly released astronom- ical dataset known as the second data release of the Dark Energy Cam- era Plane Survey (DECaPS2) reveals a staggering number of these objects in unprecedented detail. The DECaPS2 survey, which took two years to complete and produced more than 10 terabytes of data from 21,400 individual exposures, identi- fied approximately 3.32 billion ob- jects — arguably the largest such catalog compiled to date. As- tronomers and the public can explore the dataset here https://decaps.lega- cysurvey.org/viewer. This unpreced ented collection was captured by the Dark Energy Cam- era (DECam) instrument on the Víc- tor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Obser- vatory (CTIO), a Program of NSF’s NOIRLab. CTIO is a constellation of international astronomical tele- scopes perched atop Cerro Tololo in Chile at an altitude of 2200 meters (7200 feet). CTIO’s lofty vantage point gives astronomers an unri- valed view of the southern celestial hemisphere, which allowed DECam to capture the southern Galactic plane in such detail. DECaPS2 is a survey of the plane of the Milky Way as seen from the southern sky taken at optical and near-infrared wavelengths. The first أﺻﺪر ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻣﺴﺤًﺎ ﻫـﺎﺋﻼً ﻟﻠﻤﺴـﺘﻮى اﻟﻤﺠـﺮي ﻟﻤﺠـﺮة در اﻟﺘ ﺎﻧـﺔ . ﺗﺤﺘـﻮيﻣ ﻤﻮﻋـﺔ اﻟﺒ ﺎﻧـﺎت ـاﻟ ﺠﺪ ﺪة ﻋﻠﻰ ٣.٣٢ ﻣﻠ ﺎرﺟﺮمﺳﻤﺎويﻣﺬﻫﻞ ﻤﻜﻦ اﻟﻘﻮل ﺄ ﻧﮫ أﻛ ﻓﻬﺮس ﻣﻦ ﻫـﺬا اﻟﻘﺒﻴـﻞ ﺣـ . ﻵنا ﺗﻢ أﺧﺬ ﺑ ﺎﻧﺎت ﻫﺬا اﻟﻤﺴﺢ اﻟ ﻐ اﻟﻤﺴﺒﻮق ﺎﺳﺘﺨﺪام ﺎﻣ ا اﻟﻄﺎﻗـﺔ اﻟﻤﻈﻠﻤـﺔ اﻟﻤﺼـﻨّﻌﺔ ﻣـﻦ ــــﺔ ـــﺔ اﻷﻣﺮ ﻜ ــــﺔ ﻓـــﻲﻣﻌﻬــــﺪ اﻟﻌﻠــــﻮم اﻟﻮﻃﻨ ﻗﺒـــﻞ وزارة اﻟﻄﺎﻗــــﺔ اﻷﻣﺮ ﻜ - ﻣﺮﺻــــﺪ ﻛـــﺮو ﺗﻮﻟﻮﻟــــﻮ ﻓــــﻲ ﺗﺸـــ ﻠﻲ ، وﻫـــﻮ ﺑﺮ ـــﺎﻣﺞ ﺗـــﺎﺑﻊ ﻟﻤﺨﺘـــ ﻧـــﻮﻳﺮﻻب . ـــﺘﻢ وﺿـــﻊ ﺻـــﻮرة ﻣﻨﺨﻔﻀـــﺔ اﻟﺪﻗـــﺔ ﻟﺒ ﺎﻧـــﺎت ﻤﺮﺟـــﻊ ، ) DECaPS2 ( ﻋﻠـﻰﺻــﻮرة ﺗﻈﻬـﺮاﻟﺴـﻤﺎء ﺎﻣﻠـﺔ . ﻣﺮ ـﻊ اﻟﺸـﺮح ﻫـﻮ ﻋـﺮض ﺪﻗــﺔ ﺎﻣﻠـﺔ ﻟــ ـ ﺠﺰء ﺻــﻐ اﻟ ﻣﻦ ﺒ ﺎﻧﺎت DECaPS2. [DECaPS2 / DOE / FNAL / DECam/ CTIO / NOIRLab / NSF / AURA / E. . ﺳﻼو ﻚ ﺗﺢ ت درب اﻟﺘﺒﺎﻧـﺔ ﺗﺤﺘـﻮي ﻋـﲆ ﻣﺌـﺎت ا ﻠﻴﺎرات ﻣﻦ اﻟﻨ ﺠﻮم وﻣﻨﺎﻃﻖ ﺗﺸﻜﻞ اﻟﻨﺠﻮم ا ﺘﻸﻟﺌﺔ وﻏ ﻴﻮﻣًﺎ داﻛﻨﺔ ﺷـﺎﻫﻘﺔ ﻣـﻦ اﻟﻐﺒـﺎر . واﻟﻐﺎز ﻳﻌﺪ ﺗﺼﻮﻳﺮ ﻫﺬه اﻟﻜﺎﺋﻨﺎت وﻓﻬﺮ ﺳﺘﻬﺎ ﻣﻦ أﺟﻞ اﻟﺪراﺳﺔ ﻣﻬﻤﺔ ﺷﺎﻗﺔ ﻟﻜﻦ ﻣﺠﻤﻮﻋﺔ اﻟﺒﻴﺎﻧﺎت اﻟﻔﻠﻜﻴﺔ اﻟﺘﻲ ﺗـﻢ إﺻـﺪارﻫﺎ ﺣـﺪﻳﺜًﺎ وا ﻌﺮوﻓﺔ ﺑﺎﺳـﻢ اﻹﺻـﺪار اﻟﺜـﺎﻧﻲ ﻟﺒﻴﺎﻧـﺎت ﻣﺴـﺢ ﻣﺴـﺘﻮى ا ﺠـﺮة ﺑﻜ ـﺎﻣ ا اﻟﻄﺎﻗــﺔ ا ﻈﻠﻤﺔ (DECaPS2) ﺗﻜﺸﻒ ﻋﻦ ﻋﺪد ﻣﺬﻫﻞ ﻣﻦ ﻫﺬه اﻻﺟﺮام ﺑﺘﻔﺎﺻﻴﻞ ﻏ ﻣﺴﺒﻮﻗﺔ . ﻟﻘﺪ ﺣـﺪد ا ﺴـﺢ اﻟﺠﺪﻳ ـﺪ ) (DECaPS2 اﻟ ـﺬي ــــــــــــــــــــــ اﺳﺘﻐﺮق ﻋﺎﻣ ﻹﻛﻤﺎﻟـﻪ وأﻧـﺘﺞ أﻛﺜـﺮ ﻣـﻦ ﻋﴩة ﺗ اﺑﺎﻳﺖ ﻣـﻦ اﻟﺒﻴﺎﻧـﺎت ﻣـﻦ ٢١٤٠٠ ﺗﻌﺮﻳﺾ ﻓﺮدي ﻣﺎ ﻳﻘﺮب ﻣﻦ ٣.٣٢ ﺟﺮم ﻣﻠﻴﺎر ﻳﻤﻜﻦ اﻟﻘﻮل إﻧﻪ أﻛﱪ ﻛﺘـﺎﻟﻮج ﺗـﻢ ﺗﺠﻤﻴﻌـﻪ . ﺣﺘــﻰ اﻵن ﻳﻤﻜــﻦ ﻟﻠﻔﻠﻜﻴــ واﻟ ﺠﻤﻬــﻮر اﺳﺘﻜﺸﺎف ﻣﺠﻤﻮ ﻋﺔ اﻟﺒﻴﺎﻧـﺎت ﻫﻨـﺎ https: //decaps.lega- cysurvey.org/viewer. ﺗﻢ اﻟﺘﻘﺎط ﻫـﺬه ا ﺠﻤﻮﻋـﺔ ﻏـ ا ﺴـﺒﻮﻗﺔ ﺑﻮاﺳﻄﺔ أداة ﻛـﺎﻣ ا اﻟﻄﺎﻗـﺔ ا ﻈﻠﻤـﺔ دي ) ( ﻛﺎم ا ﺜﺒﺘﻪ ﻋﲆ ﺗﻠﺴﻜﻮب ﻓﻴﻜﺘﻮر م . ﺑﻼﻧﻜﻮ اﻟﺬي ﻳﺒﻠﻎ ٤ أﻣﺘـﺎر ﰲ ﻣﺮﺻـﺪ ﻛـﺮو ﺗﻮﻟﻮﻟـﻮ ـــــــ وﻫﻮ ﺑﺮﻧﺎﻣﺞ ﻟ ﻠﻤﺨﺘﱪ اﻟﻮﻃﻨﻲ ﻟﺒﺤﻮث اﻟﻔﻠـﻚ ﺑﺎﻷﺷﻌﺔ ﺗﺤﺖ اﻟــﺤﻤﺮاء اﻟﻀـﻮﺋﻴﺔ ) ﻧـﻮﻳﺮ اﻟ(ﻻب ﺘــﺎﺑﻊ ﺆﺳﺴــﺔ اﻟﻌﻠــﻮم اﻟﻮﻃﻨﻴــﺔ اﻻﻣﺮﻳﻜﻴﺔ . ﻣﺮﺻﺪ ﻛﺮو ﺗﻮﻟﻮﻟـﻮ ﻋﺒـﺎرة ﻋـﻦ ﻣﺠﻤﻮﻋﺔ ﻣﻦ اﻟﺘﻠﺴﻜﻮﺑﺎت اﻟﻔﻠﻜﻴـﺔ اﻟﺪوﻟﻴـﺔ ا ﺘﻄﻮرة ﻋﲆ ﻗﻤﺔ ﺳـ و ﺗﻮﻟﻮﻟـﻮ ﰲ ﺗﺸـﻴﲇ ﻋﲆ ارﺗﻔﺎع ٢٢٠٠ ﻣﱰ ﺗـﻮﻓﺮ ﻟﻌﻠﻤـﺎء اﻟﻔﻠـﻚ رؤﻳﺔ ﻻ ﻣﺜﻴﻞ ﻟﻬﺎ ﰲ اﻟﻨﺼﻒ اﻟﺠﻨـﻮي ﻟ ﻠﻜـﺮة اﻟﺴﻤﺎوﻳﺔ ، ﻣﻤﺎ ﺳﻤﺢ ﻟـ ﻟﻜﺎﻣ ا ) دي ﻛـﺎم ( ﺑﺎﻟﺘﻘﺎ ط ﻣﺴﺘﻮى ا ﺠﺮة اﻟﺠﻨﻮﺑﻲ ﺑﻤﺜﻞ ﻫـﺬه اﻟﺘﻔﺎﺻﻴﻞ . ﻣﺠﺮة 130 o 20 o