Free Astronomy Magazine March-April 2023 ARABIC VERSION

tected by astronomers using various telescopes. NASA recently reported that several of its high-energy space observatories spotted another black hole tidal disruption event on March 2021, and it happened in another galaxy. Unlike Hubble observations, data was collected in X-ray light from an extremely hot corona around the black hole that formed after the star was already torn apart. “However, there are still very few tidal events that are observed in ul- traviolet light given the observing time. This is really unfortunate be- cause there’s a lot of information that you can get from the ultraviolet spectra,” said Emily Engelthaler of the Center for Astrophysics | Harvard & Smithsonian (CfA) in Cambridge, Massachusetts. “We’re excited be- cause we can get these details about what the debris is doing. The tidal event can tell us a lot about a black hole.” Changes in the doomed star’s condition are taking place on the order of days or months. For any given galaxy with a quies- cent supermassive black hole at the center, it’s estimated that the stellar shredding happens only a few times in every 100,000 years. This AT2022- dsb stellar snacking event was first caught on March 1, 2022 by the All- Sky Automated Survey for Super- novae (ASAS-SN or “Assassin”), a network of ground-based telescopes that surveys the extragalactic sky roughly once a week for violent, variable, and transient events that are shaping our universe. This ener- getic collision was close enough to Earth and bright enough for the Hubble astronomers to do ultravio- let spectroscopy over a longer than normal period of time. “Typically, these events are hard to observe. You get maybe a few ob- servations at the beginning of the disruption when it’s really bright. Our program is different in that it is designed to look at a few tidal events over a year to see what hap- pens,” said Peter Maksym of the CfA. “We saw this early enough that we could observe it at these very in- tense black hole accretion stages. We saw the accretion rate drop as it turned to a trickle over time.“ The Hubble spectroscopic data are interpreted as coming from a very bright, hot, donut-shaped area of gas that was once the star. This area, known as a torus, is the size of the solar system and is swirling around a black hole in the middle.     ﻣﺠﻠﺔ Astronomy ﺎﻟﻌﺮ ﺔ ٢٣ ﻳﻮﺿـــﺢ ﻫـــﺬا اﻟﺘﺴﻠﺴـــﻞ ﻣـــﻦ اﻟﺮﺳـــﻮم اﻟﺘﻮﺿـــﻴﺤ ﺔ ﻛ ﻒ ﻤﻜﻦ ﻟﻠﺜﻘـﺐ اﻷﺳـﻮد أن ﻠـﺘﻬﻢ ﻧ ﻤًـﺎ . ﻋـﺎﺑﺮاً ١ ـﺎﻟﻘﺮ ﻣـﻦ ﺛﻘـﺐ أﺳـﻮد ﻫﺎﺋـﻞ ـﻢ ﻋـﺎد ، ﻤﺮﻧ ﻓـــــﻲوﺳـــــﻂ اﻟﻤﺠــــــﺮة .٢ − ـــــﺘﻢﺳـــــﺤﺐ اﻟﻐــــــﺎزات ـ اﻟـــــــ ـــــــﺔ اﻟﺜﻘــــــــﺐ ﺨﺎرﺟ ﺔ ﻟﻠـــــــﻨ ﻢ إﻟــــــــﻰﻣﺠـــــــﺎل ﺟﺎذﺑ اﻷﺳﻮد .٣ – ﺘﻢ ﺗﻤﺰﻖ اﻟﻨ ﻢ ـﺚ ﺗﻘـﻮم ﻗـﻮى ﺣ اﻟﻤﺪ واﻟ ـ ﺠﺰر ﺴﺤ ﮫ ﻌ ﺪًا . ٤ − ــــﺔ إﻟــــﻰﺣﻠﻘــــﺔ داﺋﺮ ــــﺔ ــــﺎ اﻟﻨ ﻤ ﺗُﺴــــﺤﺐ اﻟ ﻘﺎ اﻟﺸـــ ﻞ ﺣـــﻮل اﻟﺜﻘـــﺐ اﻷﺳـــﻮد ، وﺳﺘﺴـــﻘﻂﻓـــﻲ اﻟﻨﻬﺎ ﺔ ﻓﻲ اﻟﺜﻘﺐ اﻷﺳﻮد ، ﻣﻄﻠﻘﺔً ﻗـﺪرًا ﻫـﺎﺋﻼً ﻣﻦ اﻟﻀﻮء واﻹﺷﻌﺎع ﻋﺎﻟﻲ اﻟﻄﺎ .ﻗﺔ اﻛﺘﺸـﻒ ﻋﻠﻤـﺎء اﻟﻔﻠـﻚ ﺣـﻮاﱄ ١٠٠ ﺣــﺪث اﺿـﻄﺮاب ﰲ ا ـﺪ واﻟﺠ ـﺰر ﺣـﻮل اﻟﺜﻘ ـﻮب اﻟﺴـﻮداء ﺑﺎﺳـﺘﺨﺪام ﺗﻠﺴـﻜﻮﺑﺎت ﻣﺨﺘﻠﻔـﺔ . أﻓﺎدت وﻛﺎﻟﺔ ﻧﺎﺳـﺎ ﻣـﺆﺧﺮًا أن اﻟﻌﺪﻳـﺪ ﻣـﻦ ﻣﺮاﺻﺪﻫﺎ اﻟﻔﻀﺎﺋﻴﺔ ﻋﺎﻟﻴﺔ اﻟﻄﺎﻗـﺔ رﺻـﺪت ﺣﺪﺛًﺎ آﺧﺮ ﻻﺿﻄﺮاب ا ـﺪ واﻟﺠـﺰر ﰲ اﻟﺜﻘـﺐ اﻷﺳﻮد ﰲ ﻣﺎرس ٢٠٢١ ، وﺣﺪث ذﻟﻚ ﰲ ﻣﺠﺮة أﺧﺮى . ﻋﲆ ﻋﻜﺲ ﻣﻼﺣﻈﺎت ﻫ ﺎﺑﻞ ، ﺗﻢ ﺟﻤﻊ اﻟﺒﻴﺎﻧﺎت ﰲ ﺿﻮء اﻷﺷﻌﺔ اﻟﺴﻴﻨﻴﺔ ﻣـﻦ ﻫﺎﻟـﺔ ﺷﺪﻳﺪة اﻟﺤﺮارة ﺣﻮل اﻟﺜﻘـﺐ اﻷﺳـﻮد واﻟﺘـﻲ ـــــ ﺗﺸﻜﻠﺖ ﺑﻌﺪ أن ﺗﻤﺰق اﻟﻨﺠﻢ ﺑﺎﻟﻔﻌﻞ " . وﻣـﻊ ذﻟﻚ ﻻ ﻳﺰال ﻫﻨﺎك ﻋﺪد ﻗﻠﻴﻞ ﺟﺪًا ﻣﻦ أﺣـﺪاث ا ﺪ واﻟﺠﺰر اﻟﺘﻲ ﻳﺘﻢ رﺻﺪﻫﺎ ﰲ اﻷﺷﻌﺔ ﻓـﻮق ا ﻟﺒﻨﻔﺴﺠﻴﺔ ﺑﺎﻟﻨﻈﺮ إﱃ وﻗﺖ ا ﺮاﻗﺒـ . ﺔ ﻗﺎﻟـﺖ إﻣﻴﲇ إﻧﺠﻠﺜﺎﻟﺮ ﻣﻦ ﻣﺮﻛﺰ اﻟﻔﻴﺰﻳـﺎء اﻟﻔﻠﻜﻴـﺔ " ﻧﺤﻦ ﻣﺘﺤﻤﺴﻮن ﻷﻧﻨﺎ ﻧﺴـﺘﻄ ﻴﻊ اﻟﺤﺼـﻮل ﻋﲆ ﻫﺬه اﻟﺘﻔﺎﺻﻴﻞ ﺣﻮل ﻣﺎ ﻳﻔﻌﻠﻪ اﻟﺤﻄـﺎم . ﻳﻤﻜﻦ أن ﻳﺨﱪﻧﺎ ﺣﺪث ا ﺪ واﻟﺠﺰر اﻟﻜﺜ ﻋﻦ اﻟﺜﻘﺐ اﻷﺳﻮد ﻟﺘﻐ ن إ". ات ﰲ ﺣﺎﻟﺔ اﻟـﻨﺠﻢ ا ﻨﻜﻮب ﺗﺤﺪث ﺧﻼل أﻳﺎم أو أﺷﻬﺮ . ﺑﺎﻟﻨﺴﺒﺔ إﱃ أي ﻣﺠﺮة ﻣﻊ وﺟﻮد ﺛﻘﺐ أﺳﻮد ﻫﺎﺋﻞ ﻳُﻘﺪر أن اﻟﺘﻤﺰﻳﻖ اﻟﻨﺠﻤﻲ ﻳﺤﺪث ﻓﻘﻂ ﺑﻀﻊ ﻣﺮات ﰲ ﻛـﻞ ١٠٠٠٠٠ . ﻋـﺎم ﺗـﻢ اﻛﺘﺸـﺎف ﺣـﺪث اﻻﻟﺘﻬﺎم اﻟﻨﺠﻤﻲ ) (AT2022- dsb ﻷول ﻣﺮة ﰲ ١ ﻣــﺎرس ٢٠٢٢ ﺑﻮاﺳــﻄﺔ ا ﺴــﺢ اﻵﱄ ﻟﻠﺴﻤﺎء ا ﺴﺘﻌﺮ اﻷﻋﻈﻢ ) ASAS-SN ( وﻫﻲ ﺷﺒﻜﺔ ﻣﻦ اﻟﺘﻠﺴﻜﻮﺑﺎت اﻷرﺿﻴﺔ اﻟﺘﻲ ﺗﻘـﻮم ﺑﻤﺴﺢ اﻟﺴﻤﺎء ﺧـﺎرج ا ﺠـﺮة ﻣـﺮة واﺣـﺪة ﺗﻘﺮﻳﺒًﺎ ﰲ اﻷﺳﺒﻮع ﻟﻸﺣﺪاث اﻟﻌﻨﻴﻔﺔ وا ﺘﻐ ة واﻟﻌـﺎﺑ ﺮة . ﰲ اﻟﻜـﻮن ﻛـﺎن ﻫـﺬا اﻻﺻـﻄﺪام اﻟﻨﺸـﻂ ﻗﺮﻳﺒًـﺎ ﺑﺪرﺟـﺔ ﻛﺎﻓﻴـﺔ ﻣـ ﻦ اﻷرض و ﺳﺎﻃﻌًﺎ ﺑﺪرﺟـﺔ ﻛﺎﻓﻴـﺔ ﻟﺘﻠﺴـﻜﻮب ﻫﺎﺑـﻞ ﻟﻠﻘﻴﺎم ﺑﺎﻟﺘﺤﻠﻴﻞ اﻟﻄﻴﻔـﻲ ﻓـﻮق اﻟﺒﻨﻔﺴـﺠﻲ ﻋﲆ ﻣﺪى ﻓﱰة زﻣﻨﻴﺔ أﻃﻮل ﻣﻦ ا ﻌﺘﺎد . ﻋﺎدة ﻣﻦ اﻟﺼﻌﺐ رﺻﺪ ﻫﺬه اﻷﺣﺪاث ، رﺑﻤﺎ ﺗﺤﺼﻞ ﻋﲆ ﺑﻌﺾ اﻷرﺻﺎد ﰲ ﺑﺪاﻳﺔ اﻻﺿﻄﺮاب ﻋﻨﺪﻣﺎ ﻳﻜﻮن ﺳ ﺎﻃﻌًﺎ وﻳﺨﺘﻠﻒ ﺑﺮﻧﺎﻣﺠﻨﺎ ﻣـﻦ ﺣﻴـﺚ أﻧﻪ ﻣﺼﻤﻢ ﻟﻠﻨﻈﺮ ﰲ ﻋﺪد ﻗﻠﻴﻞ ﻣﻦ أﺣﺪاث ا ﺪ واﻟﺠﺰر ﻋﲆ ﻣﺪار ﻋﺎم ﻌﺮﻓـﺔ ﻣـﺎ ﺳـﻴﺤﺪث " ﻗﺎل ﺑﻴـﱰ ﻣﺎﻛﺴـﻴﻢ ﻣـﻦ ﻣﺮﻛـﺰ اﻟﻔﻴﺰﻳـﺎء اﻟﻔﻠﻜﻴﺔ " ﻟﻘﺪ رأﻳﻨﺎ ﻫـﺬا ﻣﺒﻜـﺮًا ﺑﻤـﺎ ﻳﻜﻔـﻲ ﺑﺤﻴﺚ ﻳﻤﻜﻨﻨﺎ رﺻﺪه ﰲ ﻣﺮاﺣﻞ ﺗﺮاﻛﻢ اﻟﺜﻘـﺐ اﻷﺳﻮد اﻟﺸﺪﻳﺪة ﻟﻠﻐﺎﻳﺔ . ﻟﻘﺪ رأﻳﻨﺎ اﻧﺨﻔـﺎض ﻣﻌـﺪل اﻟـﱰاﻛﻢ ﺣﻴـ ﺚ ﺗﺤـﻮل إﱃ اﻧﺨﻔـﺎض ﺑﻤﺮور اﻟﻮﻗﺖ " ﻳـﺘﻢ ﺗﻔﺴـ ﺑﻴﺎﻧـﺎت ﻫﺎﺑـﻞ اﻟﻄﻴﻔﻴﺔ ﺑ ﺄﻧﻬﺎ ﻗﺎدﻣﺔ ﻣﻦ ﻣﻨﻄﻘـﺔ ﺳـﺎﻃﻌﺔ ﺟﺪًا وﺳﺎﺧﻨﺔ ﺑ داﺋﺮي ﺸﻜﻞ ﻣﻦ اﻟﻐﺎز ﻛﺎﻧـﺖ ذات ﻳﻮم ﻧﺠﻢ . ﻫﺬه ا ﻨﻄﻘﺔ ا ﻌﺮوﻓﺔ ﺑﺎﺳـﻢ اﻟﺤﻠﻘﺔ ﺑ ﺤﺠﻢ اﻟﻨﻈﺎم اﻟﺸﻤﴘ وﺗﺪور ﺣـﻮل ﺛﻘﺐ أﺳﻮد ﰲ اﻟﻮﺳﻂ . ٢ ٤ ٣