Free Astronomy Magazine January-February 2025 ARABIC VERSION

sure has stripped off most of the original mass of the LMC’shalo.There’sonlyalit- tlebitleft,andit’sthissmall, compact leftover that we’re seeing now.” As the ram pressure pushes away much of the LMC’shalo,thegasslowsdown and eventually will rain into the Milky Way. But because the LMC has just passed its closest approach to the Milky Way and is moving outward into deep space again, scien- tists do not expect the whole halo will be lost. Toconductthisstudy,there- searchteamanalysedultravi- olet observations from the Mikulski Archive for Space TelescopesatSTScI.Mostul- travioletlightisblockedbyEar th’satmosphere,soit cannot be observed with ground- based telescopes. Hubble is currently the only space telescope that is tuned to detect these wavelengths oflight,sothisstudywas only possible with Hubble. The team surveyed the halo byusingthebackground lightof28brightquasars. The brightest type of active galactic nucleus, quasars are believed to be powered bysupermassiveblackholes. Shining like lighthouse bea- cons, they allow scientists to ‘see’theinterveninghalo gasindirectlythroughthe absorptionoftheback-ground light. Quasars reside throughout the Universe atextreme distances from our galaxy. The scientists used data from Hubble’s Cosmic Origins Spectrograph (COS) to detect thepresenceofthehalogas bythewayitabsorbscertain colours of light from back- ground quasars. A spectro- graph breaks light into its component wavelengths to reveal clues to the object’s state, temperature, speed, quantity, distance, and com- position. With COS, they measured the velocity of the gas around the LMC, which allowed them to determine the size of the halo. Because of its mass and prox- imity to the Milky Way, the LMC is a unique astrophysics laboratory. Seeing the LMC’s interplay with our galaxy helps scientists understand what happened in the early Universe, when galaxieswere closer together. It also shows just how messy and complicated the process of galaxy interaction is. “This is a fantastic example of the cutting-edge science still being enabled by Hub- ble’suniquecapabilities,” saidProfessorCaroleMundell, DirectorofScienceattheEu- ropean Space Agency. “This result gives us precious new insightsintothecomplexhis- tory of the Milky Way and its nearby satellite galaxies.” The team will next study the front side of the LMC’s halo, anareathathasnotyetbeen explored. “In this new programme, we are going to probe five sightlines in the regionwhere the LMC’s halo andthe Milky Way’s halo are col- liding,” said co-author Scott Lucchini of the Center for Astrophysics | Harvard & Smithsonian. “This is the lo- cation where the halos are compressed, like two bal- loons pushing against each other.”     ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 26 إن ﻣﺠﺮة درب اﻟﺘﺒﺎﻧﺔ ﺗ ﺪﻓﻊ ﻨـ ﺑﻘـﻮة ﺷﺪﻳﺪة إﱃ اﻟﺨﻠﻒ ﻟﺪرﺟﺔ أن اﻟﻀﻐﻂ اﻟﺤﺮاري ﻗـﺪ ﺟـﺮد ﻣﻌﻈـﻢ اﻟﻜﺘﻠـﺔ اﻷﺻﻠﻴﺔ ﻣﻦ ﻫﺎﻟﺔ ﺳـﺤﺎﺑﺔ ﻣـﺎ ﺟﻼن اﻟﻜﱪى ﻟﻢ ﻳﺘﺒﻘ و ﻰ ﺳﻮى اﻟﻘﻠﻴﻞ و ﻫﻮ اﻟﺒﻘﺎﻳﺎ اﻟﺼـﻐ ة ا ﻀـﻐﻮﻃﺔ اﻟﺘـﻲ ﻧﺮاﻫﺎ اﻵن . ﻣﻊ دﻓﻊ اﻟﻀﻐﻂ اﻟﻬﺎﺋﻞ ﻟﺠﺰء ﻛﺒـ ﻣ ﻦ ﻫﺎﻟﺔ ﺳﺤﺎﺑﺔ ﻣـﺎﺟﻼن اﻟﻜـﱪى اً ﺑﻌﻴﺪ ﻳﺘﺒﺎﻃﺄ اﻟﻐﺎز وﺳﻮف ﻳﻬﻄـﻞ ﰲ اﻟﻨﻬﺎﻳﺔ ﻋﲆ ﻣﺠﺮة درب اﻟﺘﺒﺎﻧﺔ و ﻟﻜﻦ ﻷن ﺳـﺤﺎﺑﺔ ﻣــﺎﺟﻼن اﻟﻜـﱪى ﻗ ـﺪ ﺗﺠﺎوزت ﻟﻠﺘﻮ أﻗﺮب ﻧﻘﻄﺔ ﻟﻬـﺎ ﻣـﻦ درب اﻟﺘﺒﺎﻧﺔ و ﺗﺘﺤﺮك ﻧﺤﻮ اﻟ ﺨﺎرج إﱃ اﻟﻔﻀﺎء اﻟﺴﺤﻴﻖ ﻣـﺮة أﺧـﺮى ﻓـﺈن ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻻ ﻳﺘﻮﻗﻌﻮن أن ﺗﻀـﻴﻊ اﻟﻬﺎﻟﺔ ﺑﺄﻛﻤﻠﻬﺎ . ﻹﺟﺮاء ﻫـﺬه اﻟﺪراﺳـﺔ ﻗـﺎم ﻓﺮﻳـﻖ اﻟﺒﺤﺚ ﺑﺘﺤﻠﻴﻞ أرﺻﺎد اﻷﺷﻌﺔ ﻓـ ﻮق اﻟﺒﻨﻔﺴــﺠﻴﺔ وذﻟــﻚ ﻣــﻦ أرﺷــﻴﻒ ﻣﻴﻜﻮﻟﺴﻜﻲ ﻟﻠﺘﻠﺴﻜﻮﺑﺎت اﻟﻔﻀﺎﺋﻴﺔ ﰲ ﻣﻌﻬﺪ ﻋﻠﻮم اﻟﻔﻀـﺎء . إن ﻣﻌﻈـﻢ ﺿـﻮء اﻷﺷـﻌﺔ ﻓــﻮق اﻟﺒﻨﻔ ﺴـﺠﻴﺔ ﻣﺤﺠﻮب ﺑﻮاﺳﻄﺔ اﻟﻐـﻼف اﻟﺠـﻮي ﻟﻠﻜﺮة اﻻرﺿﻴﺔ ﻟﺬﻟﻚ ﻻ ﻳﻤﻜﻦ رﺻـﺪه ﺑﺎﺳﺘﺨﺪام اﻟﺘﻠﺴﻜﻮﺑﺎت اﻷرﺿﻴﺔ . ﻳﻌﺘــﱪ ﺗﻠﺴــﻜﻮب ﻫﺎﺑــﻞ ﺣﺎﻟﻴــ ﺎً اﻟﺘﻠﺴﻜﻮب اﻟﻔﻀﺎﺋﻲ اﻟﻮﺣﻴﺪ اﻟﺬي ﺗﻢ ﺿــﺒﻄﻪ ﻻﻛﺘﺸــﺎف ﻫـﺬه اﻷﻃـ ﻮال ا ﻮﺟﻴﺔ ﻟﻠﻀﻮء ﻟﺬﻟﻚ ﻟـﻢ ﻳﻜـﻦ ﻣـﻦ ا ﻤﻜــﻦ إﺟ ـﺮاء ﻫــﺬه اﻟﺪراﺳ ـﺔ إﻻ ﺑﺎﺳﺘﺨﺪام ﻫﺎﺑﻞ . ﻗﺎم اﻟﻔﺮ ﻳﻖ ﺑﻤﺴﺢ اﻟﻬﺎﻟﺔ ﺑﺎﺳ ﺘﺨﺪام اﻟﻀﻮء اﻟﺨﻠﻔﻲ ﻟــ 28 اً ﻛﻮازار .ﺎً ﺳﺎﻃﻌ ﻳُﻌﺘﻘﺪ أن اﻟﻜﻮازارات وﻫﻲ أ ﻊ أﻧﻮاع اﻟﻨ ـﻮى ا ﺠﺮﻳ ـﺔ اﻟﻨﺸــﻄﺔ ﺗ ﺴـﺘﻤﺪ اﻟﻄﺎﻗ ﻣﻦ ﺔ اﻟﺜﻘﻮب اﻟﺴﻮداء اﻟﻬﺎﺋﻠﺔ إﻧﻬﺎ ﺗﻠﻤـ ﻊ ﻣﺜـﻞ ا ﻨـﺎرات وﺗﺴـﻤﺢ ﻟﻠﻌﻠﻤﺎء ﺮؤﻳﺔ ﺑ ﻏﺎز اﻟﻬﺎﻟـﺔ ا ﺘـﺪاﺧﻞ ﺑﺸﻜﻞ ﻣﺒﺎﴍ ﻣﻦ ﺧﻼل اﻣﺘﺼـﺎص اﻟﻀﻮء اﻟﺨﻠ . ﻔﻲ ﺗﻮﺟﺪ اﻟﻜـﻮازارات ﰲ ﺟﻤﻴـﻊ أﻧﺤـﺎء اﻟﻜﻮن ﻋﲆ ﻣﺴﺎﻓﺎت اً ﺟﺪ ﺑﻌﻴﺪة ﻋـﻦ . ﻣﺠﺮﺗﻨﺎ اﺳـﺘﺨﺪم اﻟﻌﻠﻤـﺎء ﺑﻴﺎﻧـﺎت ــﻣ ﻦ ﻣﻄﻴﺎف أﺻﻮل اﻟﻜﻮن اﻟﺘـﺎﺑﻊ ﻣﻦ ﻣﻄﻴﺎف أﺻـﻮل اﻟﻜـﻮن اﻟﺘـﺎﺑﻊ ﻟﺘﻠﺴﻜﻮب ﻫﺎﺑﻞ ﻟﻠﻜﺸﻒ ﻋﻦ وﺟـﻮد اﻟﻬﺎﻻت اﻟﻐﺎزﻳﺔ ﻣﻦ ﺧﻼل اﻟﻄﺮﻳﻘـﺔ اﻟﺘﻲ ﺗﻤﺘﺺ ﺑﻬﺎ أﻟ ﻮاﻧًـﺎ ﻣﻌﻴﻨـﺔ ﻣـﻦ اﻟﻀـﻮء ﻣـﻦ اﻟﻜـﻮازارات اﻟﺨﻠﻔﻴـﺔ . ﻳﻘﺴﻢ ا ﻄﻴـﺎف اﻟﻀـﻮء إﱃ أﻃـﻮال ﻣﻮﺟﻴﺔ ﻣﻜﻮﻧﺔ ﻟﻠﻜﺸﻒ ﻋﻦ أدﻟﺔ ﻋﲆ ﺣﺎﻟــﺔ اﻟﺠﺴــﻢ ودرﺟــﺔ ﺣﺮارﺗــﻪ وﴎﻋﺘﻪ وﻛﻤﻴﺘﻪ وﻣﺴﺎﻓﺘﻪ وﺗﺮﻛﻴﺒﻪ . ﺑﺎﺳﺘﺨﺪام ﻣﻄﻴـﺎف أﺻـﻮل اﻟﻜـﻮن ﻗﺎﻣﻮا ﺑﻘﻴﺎس ﴎﻋـﺔ اﻟﻐـﺎز ﺣـﻮل ﺳﺤﺎﺑﺔ ﻣﺎﺟﻼن اﻟﻜﱪى ﻣﻤﺎ ﺳـﻤﺢ ﻟﻬﻢ ﺑﺘﺤﺪﻳﺪ ﺣﺠﻢ ا . ﻟﻬﺎﻟﺔ اً ﻧﻈﺮ ﻟﻜﺘﻠﺘﻬﺎ وﻗﺮﺑﻬﺎ ﻣﻦ ﻣﺠﺮة درب اﻟﺘﺒﺎﻧﺔ ﻓﺈن ﺳﺤﺎﺑﺔ ﻣﺎ ﺟﻼن اﻟﻜﱪى ﻫﻲ ﻣﺨﺘﱪ ﻓﻴﺰﻳﺎء ﻓﻠﻜﻴﺔ ﻓﺮﻳﺪ ﻣـﻦ . ﻧﻮﻋﻪ ﺗﺴﺎﻋﺪ رؤﻳﺔ ﺗﻔﺎﻋﻞ ﺳـﺤﺎﺑﺔ ﻣﺎﺟﻼن اﻟﻜﱪى ﻣﻊ ﻣﺠﺮﺗﻨﺎ اﻟﻌﻠﻤﺎء ﻋﲆ ﻓﻬﻢ ﻣﺎ ﺣﺪث ﰲ اﻟﻜـﻮن ا ﺒﻜـﺮ ﻋﻨ ـﺪﻣﺎ ﻛﺎ ﻧــﺖ ا ﺠ ـﺮات أﻗ ـﺮب إﱃ ﺑﻌﻀﻬﺎ اﻟﺒﻌﺾ ﻛﻤـﺎ ﻳﻮﺿـﺢ ﻣـﺪى ﻓﻮﺿﻮ ﻳﺔ وﺗﻌﻘﻴـﺪ ﻋﻤﻠﻴـ ﺎت ﺗﻔﺎﻋـﻞ ا ﺠﺮات . ﻗﺎﻟﺖ اﻟﱪوﻓﻴﺴﻮرة ﻛـﺎرول ﻣﻮﻧـﺪﻳﻞ ﻣـﺪﻳﺮة ا ﻟﻌﻠـﻮم ﰲ وﻛﺎﻟــﺔ اﻟﻔﻀــﺎء اﻷوروﺑﻴﺔ :" ﻫـﺬا ﻣﺜـﺎل راﺋـﻊ ﻋـﲆ اﻟﻌﻠـﻢ ا ﺘﻄـﻮر اﻟـﺬي ﻻ ﻳـﺰال ﻳـﺘﻢ ﺗﻤﻜﻴﻨﻪ ﻣﻦ ﺧﻼل ﻗﺪرات ﺗﻠﺴـﻜﻮب ﻫﺎﺑﻞ اﻟﻔﺮﻳﺪة و ﻫﺬه اﻟﻨﺘﻴﺠﺔ ﺗﻤﻨﺤﻨﺎ رؤى ﺟﺪﻳﺪة ﺛﻤﻴﻨـﺔ ﺣـﻮل اﻟﺘـﺎرﻳﺦ ا ﻌﻘ ﺪ ﺠﺮة درب اﻟﺘﺒﺎﻧﺔ وا ﺠـﺮات اﻟﻘﺮﻳﺒﺔ ﻣﻨﻬﺎ ." ﺳﻴﻘﻮم اﻟﻔﺮﻳﻖ ﺑﻌـﺪ ذﻟـﻚ ﺑﺪراﺳـﺔ اﻟﺠﺎﻧﺐ اﻷﻣ ﺎﻣﻲ ﻣﻦ ﻫﺎﻟـﺔ ﺳـﺤﺎﺑﺔ ﻣﺎﺟﻼن اﻟﻜﱪى اﻟﺘﻲ ﻟﻢ ﺗﺴﺘﻜﺸـﻒ . ﻗﺎل ا ﺆﻟﻒ ا ﺸﺎرك ﺳﻜﻮت ﻟﻮﺗﺸﻴﻨﻲ ﻣــﻦ ﻣﺮﻛــﺰ اﻟﻔﻴﺰﻳــﺎء اﻟﻔﻠﻜﻴــﺔ | ﻫﺎرﻓﺎرد وﺳﻤﻴﺜ : " ﺴﻮﻧﻴﺎن ﺳـﻨﻘﻮم ﺑﻔﺤﺺ ﺧﻤﺴـﺔ ﺧﻄـﻮط رؤﻳـﺔ ﰲ ا ﻨﻄﻘﺔ ﺣﻴﺚ ﺗﺼﻄﺪم ﻫﺎﻟﺔ ﺳﺤﺎﺑﺔ ﻣﺎﺟﻼن اﻟﻜﱪ ى وﻫﺎﻟﺔ ﻣﺠـﺮة درب اﻟﺘﺒﺎﻧﺔ ﻫﺬا ﻫﻮ و ا ﻜﺎن اﻟﺬي ﻳﺘﻢ ﻓﻴﻪ ﺿﻐﻂ اﻟﻬﺎﻻت ﻣﺜﻞ ﺑﺎﻟﻮﻧ ﻳـﺪﻓﻌﺎن ﺗﺠﺎه ﺑﻌﻀﻬﻤﺎ ". - ﻳﻨﺎﻳﺮ ﻓﺒﺮﺍﻳﺮ 2 0 2 5 ﻳﻮﺿــﺢ ﻫــﺬا اﻟﺮﺳـﻢ اﻟﺘﺨ ﻠــﻲ ﻟﻘــﺎء ﺳــﺤﺎ ﺔ ﻣـﺎﺟﻼن اﻟﻜــ ى ﻣـﻊ اﻟ ﻬﺎﻟــﺔ اﻟﻐﺎز ــﺔ ﻟﻤﺠــﺮة در اﻟﺘ ﺎﻧــﺔ . ــﺔ ﻓــﻲ اﻟﻠﻮﺣــﺔ اﻟﻌﻠﻮ ﻓــﻲﻣﻨﺘﺼـﻒ اﻟــ ـ ﺠﺎﻧﺐ اﻷ ﻤــﻦ ــﺪأ ﺳــﺤﺎ ﺔ ﻣــﺎﺟﻼن اﻟﻜـــ ىﻓــﻲ اﻻﺻــﻄﺪام ﻋــ اﻟﻬﺎﻟــﺔ اﻷﻛـــ ﺗ ﺿﺨﺎﻣﺔ ﻟﻤﺠﺮﻨﺎ . ـﺔ اﻟﺴـﺎﻃﻌﺔ اﻟـ ﺗﻤﺜـﻞ اﻟﺼـﺪﻣﺔ اﻟﻘﻮﺳـ ﺔ اﻷرﺟﻮاﻧ ـ ﺤﺎﻓﺔ اﻷﻣ ﺎﻣ ﺔ ﻟﻬﺎﻟﺔ ﺳﺤﺎ ﺔ ﻣﺎﺟﻼن اﻟﻜ ى ـﺘﻢﺿـﻐﻄﻬﺎ ﺑ ﻨﻤـﺎ ﺗـﺪﻓﻊ واﻟـ ﻫﺎﻟـــ ﺔ در اﻟﺘ ﺎﻧــــﺔ ﻟﻠﺨﻠــــﻒﺿـــﺪ ﺳــــﺤﺎ ﺔ ﻣــــﺎﺟﻼن ا ﻟﻜـــ ى اﻟﻘﺎدﻣــــﺔ . ﻓــــﻲ اﻟﻠﻮﺣــﺔ اﻟﻮﺳــﻄﻰ ــﺘﻢ ﺗﺠﺮ ــﺪ ﺟــﺰء ﻣـــﻦ اﻟﻬﺎﻟــﺔ وﻧﻔﺨــﮫ ﻣــﺮة أﺧــﺮىﻓـــﻲ ــﺔ ﻋﻠــﻰدر اﻟﺘ ﺎﻧــﺔ ﺳــﻴﻬﻄﻞ ﻓــﻲ اﻟﻨﻬﺎ ذﻳــﻞ ﻣﺘــﺪﻓﻖ ﻣــﻦ اﻟﻐــﺎزاﻟــﺬ . ﺗُﻈﻬـــﺮ اﻟﻠﻮﺣــــﺔ اﻟﺴـــﻔﻠ ﺔ ﺗﻘــــﺪمﻫــــﺬا اﻟﺘﻔﺎﻋـــﻞ ــــﺚ ﺼـــﺒﺢ ذﻳــــﻞﺳــــﺤﺎ ﺔ ﺣ ﻣـﺎﺟﻼن اﻟﻜــ ﺸــ ﮫ اﻟﻤــﺬﻧﺐ ى اﻟــﺬ ــﺪ أﻛــ ﺗﺤﺪ . اً ﺗ ﻘــﻰﻫ ﺎﻟــﺔ ﺳــﺤﺎ ﺔ ﻣﺎﺟﻼن اﻟﻜ ى ﻧﻈـﺮ اً ﻷنﺳـﺤﺎ ﺔ ﻣـﺎﺟﻼن ا ﻟﻜـ ىﻗـﺪ ﺗﺠـﺎوز ﻟﻠﺘـﻮ أﻗـﺮ ﻧﻘﻄـﺔ ﻟﻬـﺎ ﻣـﻦ ﻣﺠـﺮة در اﻟﺘ ﺎﻧــﺔ وﺗﺘﺤـﺮك ﻟﻠ ﺨـﺎرج إﻟـﻰ اﻟﻔﻀـﺎء اﻟﺴـﺤﻴﻖ ﻣﺮة أﺧﺮى و ﻻ ﺘﻮﻗﻊ اﻟﻌﻠﻤﺎء ﻓﻘﺪان اﻟﻬﺎﻟﺔ اﻟﻤﺘ ﻘ ﺔ . ] NASA, ESA, R. Crawford (STScI [(