Free Astronomy Magazine May-June 2025 ARABIC VERSION

nucleus,” saysPucha. “Thisdramatic activityservesasabeacon,allowing us to identify hidden black holes in these small galaxies.” From their search the team identi- fied an astonishing 2500 candidate dwarf galaxies hosting an active galacticnucleus(AGN)—thelargest sample ever discovered. The sig- nificantly higher fraction of dwarf galaxies hosting an AGN (2%) rela- tivetopreviousstudies(about0.5%) is an exciting result and suggests scientists have been missing a sub- stantialnumberoflow-mass,undis- covered black holes. In a separate search through the DESI data, the team identified 300 intermediate-mass black hole candi- dates — the most extensive collec- tion to date. Most black holes are either lightweight (less than 100 times the mass of our Sun) or su- permassive(morethanonemillion times the mass of our Sun). Theblack holes in between the two ex- tremes are poorly understood, but are theorized to be the relics of the very first black holes formed in the early Universe, and the seeds of the supermassive black holes that lie at the center of large galaxies today. Yet they remain elusive, with only around 100–150 intermediate-mass black hole candidates known until now. With the large population dis- covered by DESI, scientists now have a powerful new dataset to use to study these cosmic enigmas. “The technological design of DESI was important for this project, par- ticularlyitssmallfibersize,whichal- lowed us to better zoom in on the center of galaxies and identify the subtle signatures of active black holes,” says Stephanie Juneau, asso- ciate astronomer at NSF NOIRLaband co-author of the paper. “With otherfiberspectrographswithlarger fibers, more starlight from the galaxy’s outskirts comes in and di- lutesthesignalswe’researchingfor. This explains why we managed to findahigherfractionofactiveblack holes in this work relative to previ- ous efforts.” Typically,blackholesfoundindwarf galaxies are expected to be within the intermediate-mass regime. But intriguingly, only 70 of the newly discovered intermediate-mass black hole candidates overlap with dwarf AGN candidates. This adds another layer of excitement to the findings and raises questions about blackhole formation and evolution within galaxies. “For example, is there any relation- ship between the mechanisms of black hole formation and the types of galaxies they inhabit?” Pucha said. “Our wealth of new candidates will help us delve deeper into these mysteries,enrichingourunderstand- ingofblackholesandtheirpivotal roleingalaxyevolution.”  ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 18 ﺗﻈﻬـﺮ ﻫـﺬﻩ اﻟﻔﺴ ﻔﺴــﺎءﺳﻠﺴـﻠﺔ ﻣــﻦ اﻟﺼـﻮرﻟﺜﻘـﻮبﺳــﻮداء ﻣﺘﻮﺳـﻄﺔ اﻟﻜﺘﻠـﺔ ﻣﺤﺘﻤﻠــﺔ ـﺔ ﻣﺮ ــﺐ ﺗﺼﺎﻋﺪ ﻟﻠ ﻜﺘﻠﺔ اﻟﻨ ﻤ ﺔ ﺗﻢ اﻟﺘﻘﺎﻃﻬﺎ ﺎﺳﺘﺨﺪام ﺎﻣ ا ﻫﺎﻳ ﺳﻮﺑﺮﻢ اﻟ ﻤﺘﺼﻠﺔ ﺘﻠﺴ ﻮبﺳﻮ ﺎرو . [LegacySurveys/D.Lang(PerimeterInstitute)/ NAOJ/HSCCollaboration/D.deMartin(NSFNOIRLab)&M.Zamani(NSFNOIRLab)] ﺗﻈﻬـﺮ ﻫــﺬﻩ اﻟﻔﺴ ﻔﺴـﺎءﺳﻠﺴـﻠﺔ ﻣـﻦ اﻟﺼــﻮر اﻟـ ﺗﺒـ ﻣﺠـﺮات ﻗﺰﻣــﺔ ﻣﺤﺘﻤﻠـﺔ ﺗﺴﺘﻀـ ﻒ ﻧـﻮاة ﻣﺠﺮ ــﺔ ﻧﺸﻄﺔ ﺗﻢ اﻟﺘﻘﺎﻃﻬﺎ ﺎﺳﺘﺨﺪام ﺎﻣ ا ﻫﺎﻳ ﺳﻮﺑﺮﻢ اﻟﺘﺎ ﻌﺔ ﻟﺘﻠﺴ ﻮبﺳﻮ . ﺎرو [LegacySurveys/D.Lang(PerimeterInstitute)/NAOJ/HSCCollabo- ration/D. de Martin (NSF NOIRLab) & M. Zamani (NSF NOIRLab)] " ﻳُﻌﺘﱪ ﻫﺬا اﻟﻨﺸﺎط اﻟـﺪراﻣﻲ ﺑﻤﺜﺎﺑـﺔ ﻣﻨـﺎرة ﺗﺴﻤﺢ ﻟﻨﺎ ﺑﺘﺤﺪﻳﺪ اﻟﺜﻘﻮب اﻟﺴﻮداء ﺘا ﺨﻔﻴـﺔ ﰲ ﻫﺬه ا ﺠﺮات اﻟﺼﻐ ة ". ﻣﻦ ﺧـﻼل ﺑﺤﺜـﻪ ﺣﺪ د اﻟﻔﺮﻳـﻖ 2500 ﻣﺠـﺮة ﻗﺰﻣـﺔ ﻣﺤﺘﻤﻠـﺔ ﺗ ﺴﺘﻀﻴﻒ ﻧﻮاة ﻣﺠﺮﻳﺔ ﻧﺸﻄﺔ وﻫﻲ أﻛﱪ ﻋﻴﻨﺔ ﺗﻢ اﻛﺘﺸﺎﻓﻬﺎ ﻋﲆ اﻹﻃﻼق . إن اﻟﻨﺴـﺒﺔ اﻷﻋـﲆ ﺑﻜﺜ ﻣﻦ ا ﺠﺮات اﻟﻘﺰﻣﺔ اﻟﺘﻲ ﺗﺴﺘﻀﻴﻒ ﻧﻮاة ﻣﺠﺮﻳـﺔ ﻧﺸـﻄﺔ )2 (% ﻣﻘﺎرﻧـﺔ ﺑﺎﻟﺪراﺳـﺎت اﻟﺴﺎﺑﻘﺔ ﺣﻮاﱄ ) 0.5 (% ﻫـﻲ ﻧﺘﻴﺠـﺔ ﻣﺜـ ة وﺗﺸ إﱃ أن اﻟﻌﻠﻤﺎء ﻗﺪ أﻏ ﺎً ﻮﺑ ﻔﻠﻮا ﺛﻘ ﺳـﻮداء ﻏ ﻣﻜﺘﺸﻔﺔ ذات ﻛﺘﻠـﺔ ﺗﺪﻓﻘﻴـﺔ ﻛﺒـ ة ﰲ . ﺑﺤﺚ ﻣﻨﻔﺼﻞ ﻋﱪ ﺑﻴﺎﻧﺎت أداة ( دﻳﴘ) ﺣﺪد اﻟﻔﺮﻳﻖ 300 ﺛﻘـﺐ أﺳـﻮد ﻣﺘﻮﺳـﻂ اﻟﻜﺘﻠـﺔ ﻣﺤﺘﻤﻞ وﻫﻲ ا ﺠﻤﻮﻋﺔ اﻷﻛﺜﺮ ﺷﻤﻮﻻً ﺣﺘـﻰ اﻵن . ﻣﻌﻈﻢ اﻟﺜﻘﻮب اﻟﺴـﻮداء إﻣـﺎ ﺧﻔﻴﻔـﺔ اﻟﻮزن ) أﻗﻞ ﻣﻦ 100 ﻛﺘﻠﺔ ﺿﻌﻒ اﻟﺸـﻤﺲ ( أو ﻓﺎﺋﻘﺔ اﻟﻜﺘﻠﺔ ) أﻛﺜﺮ ﻣﻦ ﻣﻠﻴﻮن ﺿﻌﻒ ﻛﺘﻠﺔ اﻟﺸﻤﺲ .( اﻟﺜﻘﻮب اﻟﺴﻮداء اﻟﻮاﻗﻌﺔ ﺑ ﻃﺮﰲ ﻫﺬا اﻟﻄﻴﻒ ﻏ ﻣﻔﻬﻮﻣﺔ ﺟﻴﺪاً وﻟﻜﻦ ﻳُﻌﺘﻘـﺪ أﻧﻬــﺎ ﺑﻘﺎﻳ ـﺎ اﻟﺜﻘـﻮب اﻟﺴـﻮداء اﻷوﱃ اﻟﺘ ـﻲ اﻟﺘﻲ ﺗﺸﻜﻠﺖ ﰲ اﻟﻜﻮن ا ﺒﻜﺮ وﺑﺬو ر اﻟﺜﻘـﻮب اﻟﺴﻮداء اﻟﻬﺎﺋﻠﺔ اﻟﺘﻲ ﺗﻘﻊ ﰲ ﻣﺮﻛـﺰ ا ﺠـﺮات اﻟﻜﺒ ة اﻟﻴﻮم وﻣﻊ ذﻟﻚ ﻻ ﺗﺰال ﻫﺬه اﻟﺜﻘـﻮب ﻧﺎدرة ﺣﻴﺚ ﻻ ﻳُﻌﺮف ﺣﺘﻰ اﻵن ﺳـﻮى ﺣـﻮاﱄ 100 - 150 ﻫﺪﻓﺎ ﻟﻠﺪراﺳﺔ ﻣﻦ ﻫﺬا اﻟﻨﻮع . وﻣﻊ اﻟﻌﺪد اﻟﻜﺒ اﻟﺬي اﻛﺘﺸﻔ أداة ﻪ ﺘ ( دﻳﴘ) أﺻﺒﺢ ﻟﺪى اﻟﻌﻠﻤـﺎء اﻵن ﻣﺠﻤﻮﻋـﺔ ﺑﻴﺎﻧـﺎت ﺟﺪﻳﺪة ﻗﻮﻳـﺔ ﻻ ﺳـﺘﺨﺪاﻣﻬﺎ ﰲ دراﺳـﺔ ﻫـﺬه اﻷ ﻟﻐﺎز اﻟﻜﻮﻧﻴﺔ . ﺗﻘﻮل ﺳﺘﻴﻔﺎﻧﻲ ﺟﻮﻧﻮ ﻋﺎ ﺔ اﻟﻔﻠﻚ ا ﺸـﺎرﻛﺔ ﰲ ﻣﺨﺘﱪ ﻧﻮﻳﺮﻻب اﻟﺘـﺎﺑﻊ ﺆﺳﺴـﺔ اﻟﻌﻠـﻮم اﻟﻮﻃﻨﻴـﺔ اﻷﻣﺮﻳﻜﻴـﺔ وا ﺆﻟﻔـﺔ ا ﺸـﺎرﻛﺔ ﰲ اﻟﺒﺤﺚ :" ﻛﺎن اﻟﺘﺼﻤﻴﻢ اﻟﺘﻜﻨﻮﻟﻮﺟﻲ ا ﺒﺘﻜـﺮ واﻟﻔﺮﻳﺪ ﻷداة دﻳﺴـﻲ ) ﺎً ﻣﻬﻤ ( ﻟﻬﺬا ا ـﴩوع وﺧﺎﺻﺔً ﺣﺠﻤﻪ اﻟﺼﻐ ﻟﻠﻐﺎﻳﺔ واﻟﺪﻗﻴﻖ ﻣﻤﺎ ﺳﻤﺢ ﻟﻨﺎ ﺑﺘﻜﺒ ﻣﺮﻛﺰ ا ﺠﺮات ﺑﺸﻜﻞ أﻓﻀﻞ وﺗﺤﺪﻳﺪ اﻟﻌﻼﻣﺎت اﻟﺪﻗﻴﻘﺔ ﻟﻠﺜﻘـﻮب اﻟﺴـﻮداء اﻟﻨﺸﻄﺔ ". ﺑﺎﺳﺘﺨﺪام ﻣﻄﻴﺎﻓﺎت أﻟﻴﺎف أﺧﺮى ذات أﻟﻴﺎف أﻛﱪ ﻳﺼﻞ ا ﺰﻳﺪ ﻣﻦ ﺿﻮء اﻟﻨﺠﻮم ﻣﻦ أﻃﺮاف ا ﺠﺮة وﻳُﻀﻌﻒ اﻹﺷـﺎرات اﻟﺘـﻲ ﻧﻘﻮم ﺑﺎﻟﺒﺤﺚ . ﻋﻨﻬﺎ ﻟﻬﺬا اﻟﺴﺒﺐ ﺗﻤﻜﻨﻨﺎ ﻣﻦ اﻟﻌﺜـﻮر ﻋـﲆ ﻧﺴـﺒﺔ أﻋﲆ ﻣﻦ اﻟﺜﻘﻮب اﻟﺴـﻮداء اﻟﻨﺸـﻄﺔ ﰲ ﻫـﺬا اﻟﻌﻤﻞ ﻣﻘﺎرﻧﺔً ﺑﺎﻟﺠﻬﻮد اﻟﺴﺎﺑﻘﺔ . ﻋـﺎدةً ﻳُﺘﻮﻗــﻊ أن ﺗﻜـﻮن اﻟﺜﻘـﻮب اﻟﺴـﻮداء ا ﻮﺟﻮدة ﰲ ا ﺠـﺮات اﻟﻘﺰﻣـﺔ ﺿـﻤﻦ ﻧﻈـﺎم اﻟﻜﺘﻠﺔ ا ﺘﻮﺳﻄﺔ وﻟﻜﻦ ﻣﻦ ا ﺜ ﻟﻼﻫﺘﻤﺎم أن 70 ﻓﻘـﻂ ﻣـﻦ اﻟﺜﻘـﻮب اﻟﺴـﻮداء ا ﺮﺷـﺤﺔ ﻣﺘﻮﺳﻄﺔ اﻟﻜﺘﻠﺔ ا ﻜﺘﺸﻔﺔ ﺣﺪﻳﺜﺎً ﺗﺘﻄﺎﺑﻖ ﻣﻊ اﻟﻨﻮى ا ﺠﺮﻳﺔ اﻟﻨﺸﻄﺔ اﻟﻘﺰﻣﺔ وﻫﺬا ﻳُﻀـﻴﻒ ﻃﺒﻘﺔ أﺧﺮى ﻣﻦ اﻹﺛـﺎرة إﱃ اﻟﻨﺘـﺎﺋﺞ وﻳﺜـ ﺗﺴـﺎؤﻻت ﺣـﻮل ﺗﻜـﻮﻳﻦ اﻟﺜﻘـﻮب اﻟﺴـﻮداء وﺗﻄﻮرﻫﺎ داﺧﻞ ا ﺠﺮات " . ﻋﲆ ﺳﺒﻴﻞ ا ﺜﺎل ﻫـﻞ ﻫﻨـﺎك أي ﻋﻼﻗـﺔ ﺑـ آﻟﻴﺎت ﺗﻜﻮﻳﻦ اﻟﺜﻘﻮب اﻟﺴﻮداء وأﻧﻮاع ا ﺠﺮات اﻟﺘﻲ ﺗﻮﺟﺪ ﻓﻴﻬﺎ ؟" ﺖﻗﺎﻟ " : ﺑﻮﺗﺸﺎ ﺳﺘﺴـﺎﻋﺪﻧﺎ وﻓـﺮة اﻟﺜﻘـﻮب اﻟﺴﻮداء ا ﺮﺷﺤﺔ اﻟﺠﺪﻳـﺪة ﺑﻜﻤﻴـﺎت ﻫﺎﺋﻠـﺔ وﻏ ﻣﺴﺒﻮﻗﺔ ﻋﲆ اﻟﺘﻌﻤـﻖ ﰲ ﻫـﺬه اﻷﻟﻐـﺎز اﻟﻜﻮﻧﻴﺔ ا ﻌﻘﺪة وا ﺤ ة ﻟﻠﻌﻘﻮل ﻣﻤﺎ ﻳُﺜـﺮي ﻓﻬﻤﻨﺎ اﻟﺸﺎﻣﻞ و ﺑﺸﻜﻞ ﻛﺒ ﻟﻠﺜﻘﻮب اﻟﺴﻮداء ودورﻫﺎ اﻷﺳﺎﳼ واﻟﺒـﺎرز ﻟﻠﻐﺎﻳـﺔ ﰲ ﺗﻄـﻮر ا ﺠﺮات وﺗﻔﺎﻋﻼﺗﻬﺎ ا ﺨﺘﻠﻔـﺔ ﻣﻘﺪﻣـﺔ رؤى ﺟﺪﻳﺪة وﻣﻬﻤﺔ ". ﻣﺎﻳﻮ - ﻳﻮﻧﻴﻮ 2 0 2 5