Free Astronomy Magazine January-February 2024 ARABIC VERSION

Using the Gemini North telescope near the summit of Maunakea in Hawai ‘ i, the team identified more than 100 of these missing-link gal- axies that show every stage of the transformation process. “Our results provide the most com- plete picture of the origin of this mysterious class of galaxy that was discovered nearly 25 years ago,” said NOIRLab astronomer Eric Peng, a co-author on the paper describing these results appearing in the jour- nal Nature . “Here we show that 106 small galaxies in the Virgo cluster have sizes between normal dwarf galaxies and UCDs, revealing a con- tinuum that fills the ‘size gap’ be- tween star clusters and galaxies.” The team compiled their sample by first looking at images from the Next Generation Virgo Cluster Sur- vey, taken with the Canada-France- Hawai ‘ i Telescope. And though they were able to identify hundreds of candidate UCD progenitors, they were unable to confirm their true nature. The obstacle was that UCDs that are surrounded by envelopes of stars are indistinguishable from nor- JANUARY-FEBRUARY 2024 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 31 ﺑﺎﺳﺘﺨﺪام ﺗﻠﺴﻜﻮب ﺟﻴﻤﻴﻨﻲ ﻧﻮرث ﺑـﺎﻟﻘﺮب ﻣﻦ ﻗﻤﺔ ﻣﻮﻧﺎﻛﻴﺎ ﰲ ﻫﺎواي ﺣﺪد اﻟﻔﺮﻳﻖ أﻛﺜﺮ ﻣـﻦ 100 ﻣـﻦ ﻫــﺬه ا ﺠــﺮات ذات ا ﻟﺤﻠﻘـﺔ ا ﻔﻘﻮدة اﻟﺘﻲ ﺗﻈﻬﺮ ﻛﻞ ﻣﺮﺣﻠﺔ ﻣﻦ ﻣﺮاﺣـﻞ ﻋﻤﻠﻴﺔ اﻟﺘﺤﻮل . " ﺗﻮﻓﺮ ﻧﺘﺎﺋﺠﻨﺎ اﻟﺼﻮرة اﻷﻛﺜﺮ اﻛﺘﻤﺎﻻ ﻷﺻـﻞ ﻫﺬه اﻟﻔﺌﺔ اﻟﻐﺎﻣﻀﺔ ﻣﻦ ا ﺠـﺮات اﻟﺘـﻲ ﺗـﻢ اﻛﺘﺸﺎﻓﻬﺎ ﻣﻨﺬ ﻣـﺎ ﻳﻘـﺮب ﻣـﻦ 25 ". ﻋﺎﻣـﺎ ـــــ ﻗﺎل ﻋﺎﻟﻢ اﻟﻔﻠﻚ ﺑﻤﺨﺘﱪ ﻧﻮﻳﺮﻻب إرﻳﻚ ﺑﻴﻨـﻎ، وﻫﻮ ﻣﺆﻟﻒ ﻣﺸﺎرك ﰲ اﻟﻮرﻗـﺔ اﻟﺘـﻲ ﺗﺼـﻒ ﻫﺬه اﻟﻨﺘﺎﺋﺞ اﻟﺘﻲ ﺗﻈﻬﺮ ﰲ ﻣﺠﻠﺔ ﻫﻨﺎ ". ﻧﻴﺘﴩ ﻧﻈﻬـﺮ أن 106 ﻣﺠـﺮات ﺻـﻐ ة ﰲ ﻋﻨﻘـﻮد اﻟﻌﺬراء ﻟﻬـﺎ أﺣﺠـﺎم ﺗـﱰاوح ﺑـ ا ﺠـﺮات اﻟﻘﺰﻣ ـﺔ اﻟﻌﺎد ﻳــﺔ وا ﺠـﺮات اﻟﻘﺰﻣـﺔ ﻏ ـ ا ﻜﺘﻤﻠﺔ ﻣﻤﺎ ﻳﻜﺸﻒ ﻋﻦ ﺳﻠﺴﻠﺔ ﻣﺘﻮاﺻـﻠﺔ " ﺗﻤﻸ ﻓﺠﻮة اﻟﺤﺠﻢ " ﺑ اﻟﻌﻨﺎﻗﻴـﺪ اﻟﻨﺠﻤﻴـﺔ ــــ . وا ﺠﺮات ﻟﻘﺪ ﻗﺎم اﻟﻔﺮﻳﻖ ﺑﺘﺠﻤﻴـﻊ ﻋﻴﻨﺘـﻪ ﺑﻮاﺳﻄﺔ أﺳـﻼف ا ﺠـﺮات اﻟﻘﺰﻣـﺔ ﻓﺎﺋﻘـﺔ اﻟﺼﻐﺮ ا ﺮﺷﺤﺔ وﻟـﻢ ﻳﺘﻤﻜ ﻨـﻮا ﻣـﻦ ﺗﺄﻛﻴـﺪ ﺎ ﻃﺒﻴﻌﺘﻬ اﻟﺤﻘﻴﻘﻴﺔ . ﻟﻘـﺪ ﻛﺎﻧـﺖ اﻟﻌﻘﺒـﺔ ﻫـﻲ أن ا ﺠـﺮات ﻏـ ا ﻜﺘﻤﻠﺔ ا ﺤﺎﻃﺔ ﺑﺄﻏﻠﻔﺔ ﻣﻦ اﻟﻨﺠﻮم ﻻ ﻳﻤﻜﻦ ﺗﻤﻴﻴﺰﻫﺎ ﻋ ﻦ ا ﺠﺮات اﻟﻌﺎدﻳﺔ اﻟﺘﻲ ﺗﻘﻊ ﺑﻌﻴﺪ اً ﻋﻦ ﻋﻨﻘﻮد اﻟﻌﺬراء . - ﻳﻨﺎﻳﺮ ﻓﺒﺮﺍﻳﺮ 2 0 2 4