Free Astronomy Magazine July-August 2025 ARABIC VERSION

L breroGalaxyisinstantlyrecognisable.Viewednearlyedgeon,thegalaxy’s ocatedaround30millionlight-yearsawayintheconstellationVirgo,theSom- softlyluminousbulgeandsharplyoutlineddiscresembletheroundedcrownand broadbrimoftheMexicanhatfromwhichthegalaxygetsitsname.Thegalaxyis toofainttobespottedwithunaidedvision,butitisreadilyviewablewithamod- est amateur telescope. [ESA/Hubble & NASA, K. Noll] From this vantage point,intricate clumpsandstrandsofduststandout against the brilliant white galactic nucleusandbulge,creatinganeffect notunlikeSaturnanditsrings—but on an epic galactic scale. Atthesametime,thisextremeangle makesitdifficulttodiscernthestruc- tureoftheSombreroGalaxy.It’snot clearwhetherit’saspiralgalaxy,like our own Milky Way, or an elliptical galaxy.Curiously,thegalaxy’sdisc seemslikeafairlytypicaldiscfora spiralgalaxy,anditsspheroidalbulge andhaloseemfairlytypicalforanel- lipticalgalaxy—butthecombination of the two components resembles neitheraspiralnoranelliptical gal- axy. Researchers have used Hubbleto investigate the Sombrero Galaxy, measuring the amount of metals (what astronomers call elements heavier than helium) in stars in the galaxy’sexpansivehalo.Thistype ofmeasurementcanilluminateagal- axy’s history, potentially revealing whether it has merged with other galaxiesinthepast.Inthecaseofthe Sombrero Galaxy, extremely metal- richstarsinthehalopointtoapossi- ble merger with a massive galaxy several billion years ago. An ancient galactic clash, hinted at by Hubble’s sensitive measurements, could ex- plain the Sombrero Galaxy’s distinc- tiveappearance.     JULY-AUGUST2025 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 41 ﻣﺠــﺮة ﺳــﻮﻣ ﺮو ﺗﻘــﻊ ﻋﻠــﻰ ُﻌــﺪ ﻧﺤــﻮ 30 ﻣ ــﺔ اﻟﻌــﺬراء ﻠﻴــﻮنﺳــﻨﺔ ﺿــﻮﺋ ﺔ ﻓــﻲ ﻮﻛ و ﻤﻜــﻦ ﺗﻤﻴ ﻫــﺎ ﺴــﻬﻮﻟﺔ ﻋﻨــﺪ رﺻــﺪﻫﺎ ﻣــﻦ اﻟــ ـ . ﺤﺎﻓﺔ ﺸــ ﮫ اﻧﺘﻔﺎﺧﻬــﺎ اﻟﻤﺮﻛــﺰي اﻟــ ـ ﺨﻔ ﻒوﻗﺮﺻـﻬﺎ ذو اﻟــ ـ ﺨﻄﻮط اﻟــ ـ ﺤﺎدة ا ﺗﺎج اﺷـﺘﻖ ﻣﻨﻬـﺎ اﺳـﻤﻬﺎ ﻟﻘ ﻌﺔ اﻟﻤﻜﺴ ﻜ ﺔ وﺣﺎﻓﺘﻬﺎ اﻟﻌﺮﻀﺔ وﻫﻲ اﻟﺼﻮرة اﻟ و ﻋﻠـﻰ اﻟـﺮﻏﻢ ﻣـﻦ أن اﻟﻤﺠــﺮة ﺧﺎﻓﺘــﺔ ﺟــﺪ اً اﻟﻤﺠــﺮدة ـــﺎﻟﻌ وﻻ ﻤﻜــﻦ رؤ ﺘﻬــﺎ إﻻ أﻧﻬــﺎ ﺗﻈﻬــﺮﺑﻮﺿــﻮح ﺎﺳــﺘﺨﺪام ﺗﻠﺴـــ ﻮب ﺻﻐ ﻟﻠﻬﻮاة ﺧﺎﺻﺔ ﻓﻲ اﻟﻠ ﺎﻟﻲ اﻟﺼﺎﻓ ﺔ واﻟﻤﻮاﻗﻊ اﻟﻤﻈﻠﻤﺔ [ESA/Hubble&NASA, K.Noll] ﻳﻮﻟﻴﻮ - ﺃﻏﺴﻄﺲ 2 0 2 5 ﺑﻨﺎء ﻋﲆ ذﻟﻚ ﺗﱪز ﻛﺘﻞ وﺧﻴﻮط ﻏﺒﺎر ﻣﻌﻘـﺪة ﻋﲆ ﺧﻠ ﻔﻴﺔ ﻧﻮاة ا ﺠﺮة اﻟﺒﻴﻀ ﺎء اﻟﻼﻣﻌﺔ ﻣﻤـﺎ ﻳﺨﻠﻖ ﺗﺄﺛ اً ﻻ ﻳﺸﺒﻪ زﺣﻞ وﺣﻠﻘﺎﺗﻪ ﺑـﻞ ﻋـﲆ ﻧﻄﺎق ﻣﺠﺮي ﻫﺎ ﺋﻞ وﰲ اﻟﻮﻗﺖ ﻧﻔﺴﻪ ﻓﺎن ﻫﺬا اﻻﻧﺤﺮاف اﻟﺸﺪﻳﺪ ﻳﺠﻌﻞ ﻣﻦ اﻟﺼـﻌﺐ ﺗﻤﻴﻴـﺰ ﺑﻨﻴﺔ ﻣﺠﺮة . ﺳﻮﻣﱪﻳﺮو ﻟﻴﺲ ﻣﻦ اﻟﻮاﺿﺢ ﻣـﺎ إذا ﻛﺎﻧﺖ ﻣﺠﺮة ﺣﻠﺰوﻧﻴﺔ ﻣﺜـﻞ ﻣﺠﺮﺗﻨـﺎ درب اﻟﺘﺒﺎﻧﺔ أو ﻣﺠﺮة إﻫﻠﻴﻠﺠﻴﺔ . وﻣﻦ اﻟﻼﻓﺖ ﻟﻠﻨﻈﺮ أن ﻗـ ﺮص ا ﺠـﺮة ﻳﺒـﺪ و ﻛﻘـﺮص ﻧﻤـﻮذﺟﻲ ﻟﻠﻤﺠﺮات اﻟﺤﻠﺰوﻧﻴﺔ ﻛﻤﺎ أن اﻧﺘﻔﺎﺧﻬﺎ اﻟﻜﺮوي وﻫﺎﻻﺗﻬﺎ ﺗﺒﺪو ﻧﻤﻮذﺟﻴﺔ ﻟﻠﻤﺠﺮات اﻹﻫﻠﻴﻠﺠﻴﺔ ﻟﻜــﻦ ﻣــﺰﻳﺞ ا ﻜــﻮﻧ ﻻ ﻳﺸــﺒﻪ ا ﺠــﺮة اﻹﻫﻠﻴﻠﺠﻴﺔ وﻻ اﻟﺤﻠﺰوﻧﻴﺔ . اﺳﺘﺨﺪم اﻟﺒﺎﺣﺜﻮن ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ ﻟﺪراﺳـﺔ ﻣﺠـﺮة ﺳـﻮﻣﱪﻳﺮو ﺣﻴﺚ ﻗﺎﻣﻮا ﺑﻘﻴﺎس ﻛﻤﻴﺔ ا ﻌﺎدن ) ﻣﺎ ﻳﺴﻤﻴ ﻪ ـــــــــــــــــــــــــــــــــــــ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻋﻨﺎﴏ أﺛﻘـﻞ ﻣـﻦ اﻟﻬﻠﻴـﻮم ﰲ ( اﻟﻨﺠﻮم ا ﻮﺟﻮدة ﰲ ﻫﺎﻟﺔ ا ﺠـﺮة ا ﺘﻮﺳـﻌﺔ . ﻳ ﻤﻜﻦ ﻟﻬﺬا اﻟﻨﻮع ﻣﻦ اﻟﻘﻴﺎس أن ﻳ ﻠﻘﻲ اﻟﻀﻮء ﺎرﻳﺦ ﻋﲆ ﺗ ا ﺠﺮة ﻣﻤﺎ ﻗـﺪ ﻳﻜﺸـﻒ ﻋﻤـﺎ إذا ﻛﺎﻧﺖ ﻗـﺪ اﻧـﺪﻣﺠﺖ ﻣـﻊ ﻣﺠـﺮات أﺧـﺮى ﰲ ا ﺎﴈ . ﰲ ﺣﺎﻟـﺔ ﻣﺠـﺮة ﺳـﻮﻣﱪﻳﺮو ﺗﺸـ اﻟﻨﺠﻮم اﻟﻐﻨﻴﺔ ﺑﺎ ﻌﺎدن ﰲ اﻟﻬﺎﻟﺔ إﱃ اﺣﺘﻤـﺎل اﻧـﺪﻣﺎﺟﻬﺎ ﻣـﻊ ﻣﺠـﺮة ﺿـﺨﻤﺔ ﻗﺒـﻞ ﻋــﺪة ﻣﻠ ﻴﺎرات ﻣﻦ اﻟﺴﻨ . ـ ﻗـﺪ ﻳﻔـ ﴪ اﺻـﻄﺪام ﻣﺠﺮي ﻗﺪﻳﻢ واﻟـﺬي أﺷـﺎرت إﻟﻴـﻪ ﻗﻴﺎﺳـﺎت ﻫﺎﺑﻞ اﻟﺪﻗﻴ ﻘﺔ ا ﻈﻬﺮ ا ﻤ ﻴﺰ ﺠﺮة ﺳﻮﻣﱪﻳﺮو . ﻫﺬه اﻷ رﺻﺎد ﻻ ﺗﻜﺸﻒ ﻓ ﻘﻂ ﻋﻦ دﻳﻨﺎﻣﻴﻜﻴﺎت ا ﺠﺮة ا ﻌﻘﺪة ﺑﻞ ﺗﻘﺪم أﻳﻀـ ﺎً ﺎً ﻓﻬﻤـ أﻋﻤـﻖ ﻟﺘﻄﻮر ا ﺠﺮات ﻋﱪ اﻟﺰﻣﻦ اﻟﻜﻮﻧﻲ ﻣﻤﺎ ﻳﻔﺘﺢ ًآﻓﺎﻗ ﺎ ﺟﺪﻳﺪة ﻟﻠﺒﺤﺚ ﰲ ﻋﻠﻢ اﻟﻔﻠﻚ .