Free Astronomy Magazine March-April 2023 ARABIC VERSION

bunch is the region dubbed Field 4, where scientists found a steadier, less turbulent environment that al- lowed hydrogen gas to collapse into a disk of stars and what scientists believe is a small dwarf galaxy in formation. “In field 4, it is likely that pre-existing large clouds of dense gas have become unstable because of the shock, and have collapsed to form new stars as we expect,” said Pierre Guillard, a researcher at the Institut d’Astrophysique de Paris and a co-investigator on the project, adding that all of the new observa- tions have significant implications for theoretical models of the impact of turbulence in the Universe. “The shock wave in the intergalactic medium of Stephan’s Quintet has formed as much cold molecular gas as we have in our own Milky Way, and yet, it forms stars at a much slower rate than expected. Under- standing why this material is sterile is a real challenge for theorists. Ad- ditional work is needed to under- stand the role of high levels of turbulence and efficient mixing be- tween the cold and hot gas.” Prior to the ALMA observations, sci- entists had little idea all of this was playing out in the Quintet’s inter- galactic medium, but it wasn’t for lack of trying. In 2010, the team used NASA’s Spitzer Space Telescope to observe Stephan’s Quintet and discovered large clouds of warm — estimated to be between 100 to 400 kelvin, or roughly -280° to 260° Fahrenheit— molecular hydrogen mixed in with the super-hot gas. “These clouds should have been de- stroyed by the large-scale shock- wave moving through the group, but weren’t. And we wanted to know, and still want to know, how did they survive?” said Appleton. To solve the mystery, the team needed more and different technological power and capability. ALMA’s first light occurred more than a year later, in late 2011 and JWST cap- tured its first images last year. The combination of these powerful re- sources has provided strikingly beau- tiful infrared images of Stephan’s Quintet, and a tantalizing, though incomplete, understanding of the relationship between the cold, warm molecular, and ionized hydro- gen gases in the wake of the giant shockwave. The team now needs spectroscopic data to unlock the secrets of the warm molecular hydrogen gas. “These new observations have given us some answers, but ultimately showed us just how much we don’t yet know,” said Appleton. “While we now have a better understanding of the gas structures and the role of turbulence in creating and sustain- ing them, future spectroscopic obser- vations will trace the motions of the gas through the doppler effect, tell us how fast the warm gas is moving, allow us to measure the temperature of the warm gas, and see how the gas is being cooled or warmed by the shockwaves. Essentially, we’ve got one side of the story. Now it’s time to get the other.”     ﻣﺠﻠﺔ Astronomy ﺎﻟﻌﺮ ﺔ ٢٨ ﺴﻠﻂ ﻫﺬا اﻟﻔ ﺪﻳﻮ اﻟﻀ ﻮء ﻋﻠﻰﺣﻘﻮل اﻟﻤﺮاﻗ ﺔ ٤ و ٥ و ٦ اﻛﺘﺸﻒﻓﻴﻬـﺎ اﻟﻔﺮ ـﻖ وﻫﻲ اﻟﻤﻨﺎﻃﻖ اﻟ إﻟـــﻰ إﻧﺸـــﺎء ﻣﺼـــﻨﻊ ﻹﻋـــﺎدة ﺗـــﺪوﻳ أن اﻻﺿـــﻄﺮاب اﻟﻨـــﺎ ﻢ ﻋـــﻦ ﻣﻮﺟـــﺔ اﻟﺼـــﺪﻣﺔ اﻟﻌﻤﻼﻗـــﺔ ﻗـــﺪ أد ﺮ اﻟﻐـــﺎز ـ اﻟـــــ ـــــﺎرد اﻟـــــﺪاﻓﺊ واﻟ ﺠﺰ ـــــﺔ اﻟ اﻟﺴـــــﻠﻮﻛ ﺎت اﻟﻬﻴ ﻠ وﺗﻤﻜـــــ ـــــﺖ ـــــﺔ ﻟﻠ ﻮﻧﺘ ﻐﺮ . ﻛﺸـــــﻒ اﻟـــــ ـ ) ﺤﻘﻞ ٦( ﻋـــــﻦ اﻟﻤﺆﺷﺮ ات اﻷوﻟﻰ ﻟﻤﺼﻨﻊ إﻋﺎدة اﻟﺘﺪوﻳﺮ ﺣ ﺚ ﺗﻤﺪ اﻟﻤﻨﻄﻘﺔ ﺳﺤﺎ ﺔ ﻋﻤﻼﻗﺔ ﻣﻦ اﻟـ ـ ـﺎردة إﻟـﻰ ﺠﺰ ﺌﺎت اﻟ اﻟــﺪاﻓﺊ ﺸـــ ﻞ ﻣﺘﻜــﺮر ــﺰ ا ــﺪروﺟ ذﻳــﻞ ﻣــﻦ ﻏــﺎزاﻟﻬ . ﻛﺸــﻒ اﻟــ ـ ) ﺤﻘﻞ ٥( ﺸــ ﻞ ﺻــﺎدم ﻋــﻦ ﺗﺼـــﺎدم ــﺚ اﺻــﻄﺪﻣ ﻋــﺎﻟﻲ اﻟﺴــﺮﻋﺔ ﺣ ــ ﺖ رﺻﺎﺻــﺔ ﻣــﻦ اﻟﻐــﺎز ﺴــﺤﺎ ﺔ ﺟﺰ ﺌ ﺔ ــﻮﻳﻦ ﺣﻠﻘــﺔ ورـــﻂ إﻟــﻰ ﺗ ﻣﻤــﺎ أد ﺘاﺛﻨ ﻣﻦ ﺳﺤﺐ اﻟﻐﺎز اﻟ ﺎرد ﻣﻌًﺎ ـ اﻟـ . ) ﺤﻘﻞ ٤( ـﺔ ﻫـﻮ ﺑﻴﺌـﺔ ﻣﺴـﺘﻘﺮة ﻧﺴـﺒ ًﺎ اﻷﻛـ ﻃﺒ ﻌ ﻣﻤـﺎ ﺴـﻤﺢ ﻨﻤـﻮ ـﻮن ﻣﺠـﺮة ﻣـﺎ ﻗـﺪ ﻳ ﻗﺰﻣـﺔ ﺻـﻐ ة . [ALMA (ESO / NAOJ / NRAO) / JWST / P. أ ﻠ ﺘـﻮن ) ﻣﻌﻬـﺪ ﺎﻟ ﻔﻮر ﺎ ﻟﻠﺘﻜﻨﻮﻟﻮﺟ ﺎ ( ، ﺑﻲﺳﺎﻛﺴﺘﻮن .(NRAO / AUI / NSF)] ﻣﺎرس أﺑﺮﻳﻞ 2023 ﻟﻜﻦ اﻟﻌﻠﻤﺎء ﻟﻴﺴﻮا ﻣﺘﺄﻛﺪﻳﻦ ﺗﻤﺎﻣًﺎ ﻣﻤﺎ ﻳﻌﻨﻴﻪ ذﻟﻚ ﻷﻧﻬﻢ ﻟﻴﺲ ﻟﺪﻳﻬﻢ ﺑﻴﺎﻧﺎت رﺻﺪ ﻣﻔﺼـﻠﺔ ﻟﻠﻐﺎز اﻟﺪاﻓﺊ . ﻗـﺎل ﺑﻴـﻮرن إﻳﻤـﻮﻧﺘﺲ ﻋـﺎﻟﻢ اﻟﻔﻠﻚ ﰲ ا ﺮﺻﺪ اﻟﻮﻃﻨﻲ ﻟﻌﻠﻢ اﻟﻔﻠﻚ اﻟﺮادﻳﻮي اﻟﺘﺎﺑﻊ ﺆﺳﺴﺔ اﻟﻌﻠـﻮم اﻟﻮﻃﻨﻴـﺔ اﻷﻣﺮﻳﻜﻴـﺔ واﻟﺒﺎﺣﺚ ا ﺸﺎرك ﺑﻬﺬا ا ﴩوع : ﻗـﺪ ﺗﻜـﻮن اﻟﺴﺤﺎﺑﺔ اﻟﺠﺰﻳﺌﻴﺔ اﻟﺘﻲ ﺗﺨـﱰق اﻟﻐـﺎز ﺑـ ا ﺠﺮات ، وﺗﱰك اﻟﻔـﻮﴇ ﰲ أﻋﻘﺎﺑﻬـﺎ أﻣـﺮًا ﻧﺎدرًا وﻟﻢ ﻳـﺘﻢ ﻓﻬﻤـﻪ ﺑﺎﻟﻜﺎﻣـﻞ ﺑﻌـ ﺪ، ﻟﻜـﻦ ﺑﻴﺎﻧﺎﺗﻨﺎ ﺗﻈﻬﺮ أﻧﻨﺎ اﺗﺨـﺬﻧﺎ اﻟﺨﻄـﻮة اﻟﺘﺎﻟﻴـﺔ ﻟ ﻔﻬــﻢ اﻟﺴــﻠﻮك اﻟﺼــﺎدم ودورة اﻟﺤﻴــﺎة ا ﻀ ﻄﺮﺑﺔ ﻟﺴﺤﺐ اﻟﻐﺎز اﻟﺠﺰﻳﺌﻲ ﰲ ﺧﻤﺎﺳﻴﺔ ﺳﺘﻴﻔﺎن رﺑﻤﺎ ﺗﻜـﻮن ا ﻨﻄﻘـﺔ اﻟﺘـﻲ ﻳُﻄﻠـﻖ ﻋﻠﻴﻬﺎ اﺳﻢ اﻟﺤﻘﻞ اﻟﺮاﺑﻊ ﻫﻲ أﻛﺜـﺮ ا ﻨـﺎﻃﻖ " ﻃﺒﻴﻌﻴﺔ " ، ﺣﻴﺚ وﺟﺪ اﻟﻌﻠﻤـﺎء ﺑﻴﺌـﺔ أﻛﺜـﺮ ﺛﺒﺎﺗًﺎ وأﻗﻞ اﺿﻄﺮاﺑًﺎ أدت إﱃ اﻧﺨﻔـﺎض ﻏـﺎز اﻟﻬﻴﺪروﺟ إﱃ ﻗﺮص ﻣﻦ اﻟﻨﺠﻮم وﻣﺎ ﻳﻌﺘﻘﺪ اﻟﻌﻠﻤﺎء أﻧﻪ ﻣﺠﺮة ﻗﺰﻣﺔ ﺻﻐ ة ﰲ اﻟﺘﻜﻮﻳﻦ . ﻳﺤﺘﻤﻞ ﰲ اﻟﺤﻘﻞ اﻟﺮاﺑﻊ أن ﺗﻜـﻮن اﻟﺴـﺤﺐ اﻟﻜﺒ ة ا ﻮﺟﻮدة ﻣﺴﺒﻘًﺎ ﻣﻦ اﻟﻐـﺎز اﻟﻜﺜﻴـﻒ ﻏـ ﻣﺴـﺘﻘﺮة ﺑﺴـﺒﺐ اﻟﺼـﺪﻣﺔ واﻧﻬـﺎرت ﻟﺘﺸﻜﻞ ﻧﺠﻮﻣًﺎ ﺟﺪﻳﺪة ﻛﻤﺎ ﻧﺘﻮﻗـﻊ ﺑﺤﺴـﺐ ﺑﻴـ ﺟـﻴﻼرد ، اﻟﺒﺎﺣـﺚ ﰲ ﻣﻌﻬـﺪ اﻟﻔﻴﺰﻳـﺎء اﻟﻔﻠﻜﻴﺔ ﰲ ﺑﺎرﻳﺲ واﻟﺒﺎﺣﺚ ا ﺸـﺎرك ﰲ ﻫـﺬا ا ﴩوع ﻣﻀﻴﻔًﺎ أن ﺟﻤﻴﻊ اﻷرﺻﺎد اﻟﺠﺪﻳـﺪة ﻟﻬﺎ آﺛﺎر ﻛﺒ ة ﻋﲆ اﻟﻨﻤﺎذج اﻟﻨﻈﺮﻳـﺔ ﻟﺘـﺄﺛ اﻻﺿــﻄﺮاﺑﺎت ﰲ اﻟﻜــﻮن . " ﺷـﻜﻠﺖ ﻣﻮﺟ ـﺔ اﻟﺼﺪﻣﺔ ﰲ اﻟﻮﺳﻂ ﺑ ا ﺠـﺮات ﻟﺨﻤﺎﺳـﻴﺔ ﺳﺘﻴﻔﺎن اﻟﻜﺜ ﻣﻦ اﻟﻐﺎز اﻟﺠﺰﻳﺌﻲ اﻟﺒﺎرد ﻛﻤﺎ ﻫﻮ اﻟﺤﺎل ﻟﺪﻳﻨﺎ ﰲ ﻣﺠﺮﺗﻨﺎ درب اﻟﺘﺒﺎﻧﺔ وﻣـﻊ ذﻟﻚ ﻓﺈﻧﻬﺎ ﺗﺸﻜﻞ اﻟﻨﺠﻮم ﺑﻤﻌﺪل أﺑﻄﺄ ﺑﻜﺜـ ﻣﻤﺎ ﻛﺎن . ﻣﺘﻮﻗﻌًﺎ إن ﻓﻬﻢ ﺳﺒﺐ ﻋﻘـﻢ ﻫـﺬه ا ﺎدة ﻳﻤﺜﻞ ﺗﺤﺪﻳًﺎ ﺣﻘﻴﻘﻴًﺎ ﻟﻠﻤﻨﻈﺮﻳﻦ . ﻫﻨـﺎك ﺣﺎﺟﺔ إﱃ ﻋﻤﻞ إﺿﺎﰲ ﻟﻔﻬﻢ دور ا ﺴـﺘﻮﻳﺎت اﻟﻌﺎﻟﻴﺔ ﻣﻦ اﻻﺿﻄﺮاب واﻟﺨﻠﻂ اﻟ ﻔﻌـﺎل ﺑـ اﻟﻐﺎز اﻟﺒﺎرد واﻟﺴﺎﺧﻦ . ﻗﺒـﻞ أرﺻـﺎد ﻣﺮﺻـﺪ ( أ ﺎ) ﻟﻢ ﻳﻜﻦ ﻟﺪى اﻟﻌﻠﻤﺎء ﻓﻜﺮة ﻋﻦ ﻛﻞ ﻫـﺬا ﻛﺎن ﻳﺤﺪث ﰲ وﺳﻂ ا ﺠﺮات اﻟﺨﻤﺎﳼ ، ﻟﻜﻦ ﻟـــﻢ ﻳﻜ ــﻦ ﺑﺴ ــﺒﺐ ﻧﻘ ــﺺ ا ﺤﺎوﻟ ــﺔ . ـــــــــــــ اﺳﺘﺨﺪم اﻟﻔﺮﻳـﻖ ﰲ ﻋـﺎم ٢٠١٠ ﺗﻠﺴـﻜﻮب ﺗﻠﻜﺴﻮب ﺳﺒﻴﺘﺰر اﻟﻔﻀـﺎﺋﻲ اﻟﺘـﺎﺑﻊ ﻟ ﻮﻛﺎﻟـﺔ ﻧﺎﺳﺎ ﺮاﻗﺒﺔ ﺧﻤﺎﺳـﻴﺔ ﺳـﺘﻴﻔﺎن واﻛﺘﺸـﻔﻮا ﺳﺤﺒًﺎ ﻛﺒ ة ﻣﻦ اﻟﺪفء ﺗﱰاوح ﻣﺎ ﺑـ ١٠٠ إﱃ ٤٠٠ ﻛﻠﻔﻦ أو ﻣﺎ ﻳﻘﺮب ﻣﻦ - ٢٨٠ درﺟـﺔ إﱃ ٢٦٠ درﺟﺔ ﻓﻬﺮﻧﻬﺎﻳﺖ ﻫﻴﺪروﺟ ﺟﺰﻳﺌﻲ ﻣﺨﺘﻠﻂ ﻣﻊ اﻟﻐﺎز ﺷﺪﻳﺪ اﻟﺴﺨﻮﻧﺔ . ﻣـﻦ ﻛﺎن ا ﻔﱰض ان ﺗﺪﻣﺮ ﻫﺬه اﻟﻐﻴﻮم ﺑﻔﻌﻞ ﻣﻮﺟـﺔ اﻟﺼﺪﻣﺔ اﻟﻮاﺳﻌﺔ اﻟﻨﻄـﺎق اﻟﺘـﻲ ﺗﻤـﺮ ﻋـﱪ ا ﺠ ﻤﻮﻋﺔ ، ﻟﻜﻦ ﻟـﻢ ﻳﺤـﺪث ذﻟـﻚ وأردﻧـﺎ أن ﻧﻌﺮ ف ، وﻣﺎ زﻟﻨﺎ ﻧﺮﻳﺪ أن ﻧﻌﺮف ﻛﻴـﻒ ﻧﺠـﺖ ﻗﺎل أﺑﻠﻴﺘﻮن : ﻟﺤﻞ اﻟﻠﻐـﺰ اﺣﺘـﺎج اﻟﻔﺮﻳـﻖ إﱃ ا ﺰﻳـﺪ ﻣـﻦ اﻟﻘـﻮة واﻟﻘـﺪرات اﻟﺘﻜ ﻨﻮﻟﻮﺟﻴــﺔ ا ﺨﺘﻠﻔﺔ . ﻇﻬﺮ أول ﺿﻮء أ ـﺎ ) ﺮﺻـﺪ ( ﺑﻌـﺪ أﻛﺜﺮ ﻣﻦ ﻋﺎم ﰲ أواﺧـﺮ ﻋـﺎم ٢٠١١ واﻟـﺘﻘﻂ ﺗﻠﺴﻜﻮب ﺟﻴﻤﺲ وﻳـﺐ ﺻـﻮره اﻷوﱃ اﻟﻌـﺎ م ا ﺎﴈ وﻗﺪ أﺗﺎح اﻟﺠﻤﻊ ﺑـ ﻫـﺬه ا ﺼـﺎدر اﻟﻘﻮﻳﺔ ﺻﻮرًا راﺋﻌﺔ اﻟﺠﻤﺎل ﺑﺎﻷﺷـﻌﺔ ﺗﺤـﺖ ـــ اﻟﺤﻤﺮاء ﻟﺨﻤﺎﺳﻴ ﺔ ﺳـﺘﻴﻔﺎن وﻓﻬﻤًـﺎ ﻣﺤـ ًا وإن ﻛﺎن ﻏـ ﻛﺎﻣـﻞ ﻟﻠﻌﻼﻗـﺔ ﺑـ ﻏـﺎزات اﻟﻬﻴ ـﺪروﺟ اﻟﺒ ـﺎردة واﻟﺠﺰﻳﺌﻴــﺔ اﻟﺪاﻓﺌ ـﺔ وا ﺘﺄﻳﻨﺔ ﰲ أﻋﻘﺎب ﻣﻮﺟﺔ اﻟﺼﺪﻣﺔ اﻟﻌﻤﻼﻗﺔ . ﻳﺤﺘﺎج اﻟﻔﺮﻳﻖ اﻵن إﱃ ﺑﻴﺎﻧﺎت ﻃﻴﻔﻴﺔ ﻟﻜﺸﻒ أﴎار ﻏـﺎز اﻟﻬﻴـﺪروﺟ اﻟﺠﺰﻳﺌـﻲ اﻟـﺪاﻓﺊ . ﻳﻘﻮل أﺑﻠﻴﺘﻮن " : أﻋﻄﺘ ﻨﺎ ﻫﺬه اﻷرﺻﺎد اﻟﺠﺪﻳﺪة ﺑﻌﺾ اﻹﺟﺎﺑﺎت ﻟﻜﻨﻬﺎ أﻇﻬﺮت ﻟﻨﺎ ﰲ اﻟﻨﻬ ﺎﻳـﺔ ﻣﻘﺪار ﻣﺎ ﻻ ﻧﻌﺮﻓﻪ ﺣﺘﻰ اﻵن ، ﻓ ﺒﻴﻨﻤـﺎ ﻟـﺪﻳﻨﺎ اﻵن ﻓﻬــﻢ أﻓﻀــﻞ ﻟﻬﻴﺎﻛــﻞ اﻟﻐــﺎز ودور ا ﻻﺿـﻄﺮاب ﰲ ﺗﻜﻮﻳﻨﻬـﺎ واﺳـﺘﺪاﻣﺘﻬﺎ ﻓـﺈن اﻻرﺻﺎد اﻟﻄﻴﻔﻴﺔ ا ﺴﺘﻘﺒﻠﻴﺔ ﺳﺘﺘﺒﻊ ﺣﺮﻛﺎت ا ﻟﻐﺎز ﻣﻦ ﺧﻼل ﺗﺄﺛ دوﺑﻠﺮ وﺗﺨﱪ ﻧـﺎ ﺑﻤـﺪى ﴎﻋﺔ ﺗﺤـ ﺮك اﻟﻐـﺎز اﻟـﺪاﻓﺊ واﻟﺴـﻤﺎح ﻟﻨـﺎ ﻘﻴﺎسﺑ ﺣﺮارة اﻟﻐﺎز اﻟﺪاﻓﺊ وﻣﻌﺮﻓﺔ ﻛﻴﻔﻴـﺔ ﺗﱪﻳﺪ اﻟﻐﺎز أو ﺗﺴـﺨﻴﻨﻪ ﺑﻮاﺳـﻄﺔ ﻣﻮﺟـﺎت اﻟﺼﺪﻣﺔ . ﻳﻮﺟﺪ ﺟﺎﻧﺐ واﺣﺪ ﻣﻦ اﻟﻘﺼﺔ ﺎن ﺣ اﻟﻮﻗﺖ اﻵن ﻟﻠﺤﺼﻮل ﻋﲆ اﻵﺧﺮ .