Free Astronomy Magazine November-December 2022 ARABIC VERSION

E ASTRO PUBLISHING 19 SO’s Very Large Telescope (VLT) has imaged the result of a spec- tacular cosmic collision — the galaxy NGC 7727. This giant was born from the merger of two galax- ies, an event that started around a billion years ago. At its centre lies the closest pair of supermassive black holes ever found, two objects that are destined to coalesce into an even more massive black hole. Just as you may bump into someone on a busy street, galaxies too can bump into each other. But while galactic interactions are much more violent than a bump on a busy street, individual stars don’t gener- ally collide since, compared to their sizes, the distances between them are very large. Rather, the galaxies dance around each other, with grav- ity creating tidal forces that dramat- ically change the look of the two dance partners. ‘Tails’ of stars, gas and dust are spun around the galax- ies as they eventually form a new, merged galaxy, resulting in the dis- ordered and beautifully asymmetri- cal shape that we see in NGC 7727. The consequences of this cosmic bump are spectacularly evident in this image of the galaxy, taken with the FOcal Reducer and low disper- sion Spectrograph 2 (FORS2) instru- ment at ESO’s VLT. While the galaxy was previously captured by another ESO telescope, this new image shows more intricate details both within the main body of the galaxy and in the faint tails around it. In this ESO VLT image we see the tangled trails created as the two galaxies merged, stripping stars and dust from each other to create the spectacular long arms embracing NGC 7727. Parts of these arms are dotted with stars, which appear as bright blue-purplish spots in this image. Also visible in this image are two bright points at the centre of the galaxy, another telltale sign of its dramatic past. The core of NGC 7727 still consists of the original two galactic cores, each hosting a super- massive black hole. Located about 89 million light-years away from Earth, in the constellation of Aquar- ius, this is the closest pair of super- massive black holes to us. The black holes in NGC 7727 are ob- served to be just 1600 light-years apart in the sky and are expected to merge within 250 million years, the blink of an eye in astronomical time. When the black holes merge they will create an even more massive black hole. The search for similarly hidden supermassive black hole pairs is expected to make a great leap forward with ESO’s upcoming Extremely Large Telescope (ELT), set to start operating later this decade in Chile’s Atacama Desert. With the ELT, we can expect many more of these discoveries at the centres of galaxies. Our home galaxy, which also sports a supermassive black hole at its cen- tre, is on a path to merge with our closest large neighbour, the An- dromeda Galaxy, billions of years from now. Perhaps the resulting galaxy will look something similar to the cosmic dance we see in NGC 7727, so this image could be giving us a glimpse into the future.    اﻟ ﻗﺎم ﺘﻠﺴﻜﻮب ا ﻟﻜﺒ ﺟﺪاً اﻟﺘـﺎﺑﻊ ﻟﻠﻤﺮﺻـﺪ اﻷوروﺑﻲ اﻟـﺠﻨﻮﺑﻲ ﺑﺘﺼﻮﻳﺮ ﻧﺘﻴﺠﺔ ﺗﺼـﺎدم ﻛﻮﻧﻲ ﻣﻤﻴﺰ - ا ﺠﺮة NGC 7727 . وﻟـﺪ ﻫـﺬا اﻟﻌﻤﻼق ﻣﻦ اﻧﺪﻣﺎج ﻣﺠﺮﺗ ، وﻫﻮ ﺣﺪث ﺑﺪأ ﻣﻨﺬ ﺣﻮاﱄ ﻣﻠﻴﺎر ﺳﻨﺔ . ﻳﻮﺟﺪ ﰲ ﻣﺮﻛﺰه أﻗﺮب زوج ﻣﻦ اﻟﺜﻘﻮب اﻟﺴﻮداء ﻓﺎﺋﻘﺔ اﻟﻜﺘﻠـﺔ ﺗـﻢ اﻟﻌﺜﻮر ﻋﻠﻴﻪ ﻋﲆ اﻹﻃﻼق ، وﻫﻤـﺎ ﺟﺴـﻤﺎن ﻣﻘ ﺪر ﻟﻬﻤﺎ اﻻﻧـﺪﻣﺎج ﰲ ﺛﻘـﺐ أﺳـﻮد أﻛﺜـﺮ . ﺿﺨﺎﻣﺔ ﻣﺜﻠﻤﺎ ﻗﺪ ﺗﺼﻄﺪم ﺑﺸـﺨﺺ ﻣـﺎ ﰲ ﺷﺎرع ﻣﺰدﺣﻢ ، ﻳﻤﻜﻦ أن ﺗﺼﻄﺪم ا ﺠـﺮات أﻳﻀًﺎ ﺑﺒﻌﻀـﻬﺎ اﻟـﺒﻌﺾ . وﻟﻜـﻦ ﰲ ﺣـ أن اﻟﺘﻔﺎﻋﻼت ا ﺠﺮﻳﺔ أﻛﺜـﺮ ﻋﻨﻔًـﺎ ﺑﻜﺜـ ﻣـﻦ اﻟﺘﺼﺎدم ﰲ ﺷـﺎرع ﻣـﺰدﺣﻢ ، ﻓـﺈن اﻟﻨﺠـﻮم اﻟﻔﺮدﻳﺔ ﻻ ﺗﺘﺼـﺎدم ﺑﺸـﻜﻞ ﻋـﺎم ﻧﻈـﺮًا ﻷن ا ﺴــﺎﻓﺎت ﺑﻴﻨﻬــﺎ ﻛﺒــ ة ﺟــﺪًا ﻣﻘﺎرﻧــﺔ ﺑﺄﺣﺠﺎﻣﻬﺎ . ﺑﺪﻻ ﻣﻦ ذﻟﻚ ﺗـﱰاﻗﺺ ا ﺠـﺮات ﺣﻮل ﺑﻌﻀﻬﺎ اﻟﺒﻌﺾ ، ﺣﻴﺚ ﺗﺨﻠﻖ اﻟﺠﺎذﺑﻴﺔ ﻗﻮى ا ﺪ اﻟﺘﻲ ﺗﻐ ﺷﻜﻞ اﻟﴩﻳﻜ اﻟﺮاﻗﺼ ﺑﺸﻜﻞ ﻛﺒ . ذﻳـﻮل " ﺗﺪور " اﻟﻨﺠـﻮم واﻟﻐـﺎز واﻟﻐﺒﺎر ﺣﻮل ا ﺠﺮات ﻷﻧﻬﺎ ﺗﺸﻜﻞ ﰲ اﻟﻨﻬﺎﻳﺔ ﻣﺠﺮة ﻣﺪﻣﺠﺔ ﺟﺪﻳﺪة ، ﻣﻤﺎ ﻳﺆدي إﱃ اﻟﺸﻜ ﻞ ﻏ ا ﻨﺘﻈﻢ وﻏ ا ﺘﻤﺎﺛﻞ ﺑﺸﻜﻞ ﺟﻤﻴﻞ اﻟﺬي ﻧﺮاه ﰲ NGC 7727 . ﻋﻮاﻗﺐ ﻫـﺬا اﻟﺘﺼـﺎدم اﻟﻜﻮﻧﻲ ﻫﻲ واﺿـﺢ ﺑﺸـﻜﻞ ﻣـﺬﻫﻞ ﰲ ﻫـﺬه اﻟﺼﻮرة ﻟﻠﻤﺠﺮة ، ﺑﻮاﺳـﻄﺔ ا ﺮﺻـﺪ اﻟﻜﺒـ ﺟﺪا اﻟﺘﺎﺑﻊ ﻟﻠﻤﺮﺻﺪ اﻷوروﺑﻲ اﻟﺠﻨﻮﺑﻲ . ﺑﻴﻨﻤﺎ ﺗﻢ اﻟﺘﻘﺎط ا ﺠﺮة ﻣﺴﺒﻘًﺎ ﺑﻮاﺳﻄﺔ ﺗﻠﺴﻜﻮب ﺗﻠﺴﻜﻮب آﺧﺮ ﺗﺎﺑﻊ ﻟﻠﻤﺮﺻﺪ اﻷوروﺑﻲ ، ﺗُﻈﻬﺮ ﻫﺬه اﻟﺼﻮرة اﻟﺠﺪﻳﺪة ﺗﻔﺎﺻﻴﻞ أﻛﺜﺮ ﺗﻌﻘﻴـﺪًا داﺧﻞ ﻛﻞ ﻣﻦ اﻟﺠﺴﻢ اﻟﺮﺋﻴﴘـ ﻟﻠﻤﺠـﺮة وﰲ ذﻳﻮﻟﻬﺎ اﻟﺒﺎﻫﺘﺔ ا ﺤﻴﻄﺔ ﺑﻬـﺎ . ﻧـﺮى ﰲ ﻫـﺬه اﻟﺼﻮرة ا ﺴـﺎرات ا ﺘﺸـﺎﺑﻜﺔ اﻟﺘـﻲ ﻧﺸـﺄت ﻋﻨﺪﻣﺎ اﻧﺪﻣﺠﺖ ا ﺠﺮﺗﺎن ، ﻣﻤﺎ أدى إﱃ ﺗﺠﺮﻳﺪ اﻟﻨﺠﻮم واﻟﻐﺒﺎر ﻣﻦ ﺑﻌﻀﻬﻤﺎ اﻟﺒﻌﺾ ﻹﻧﺸﺎء أذرع ﻃﻮﻳﻠﺔ ﺗﺤﺘﻀﻦ NGC 7727 . أﺟﺰاء ﻣﻦ ﻫﺬه اﻷذرع ﻣﻨﻘﻄﺔ ﺑﺎﻟﻨﺠﻮم ، واﻟﺘﻲ ﺗﻈﻬـﺮ ﻋﲆ ﻫﻴﺌﺔ أرﺟﻮاﻧﻴﺔ زرﻗﺎء ﻻﻣﻌـﺔ . اﻟﺒﻘـﻊ ﰲ ﻫﺬه اﻟﺼﻮرة . ﺗﻈﻬﺮ أﻳﻀًﺎ ﰲ ﻫـﺬه اﻟﺼـﻮرة ﻧﻘﻄﺘﺎن ﺳﺎﻃﻌﺘﺎن ﰲ ﻣﺮﻛﺰ ا ﺠـﺮة ، وﻫـﻲ ﻋﻼﻣﺔ أﺧﺮى ﺗﺪل ﻋﲆ ﻣﺎ ﺿـﻴﻬﺎ اﻟـﺪراﻣﻲ ﻻ . ﻳﺰال ﻗﻠﺐ NGC 7727 ﻳﺘﻜـﻮن ﻣـﻦ ﻧـﻮاﺗ ﻣﺠﺮﺗ أﺻﻠﻴﺘ ، ﻳﺤﺘﻮي ﻛﻞ ﻣﻨﻬﻤـﺎ ﻋـﲆ ﺛﻘﺐ أﺳﻮد ﻓﺎﺋﻖ اﻟﻜﺘﻠﺔ . ﻳﻘﻊ ﻋﲆ ﺑﻌﺪ ﺣﻮاﱄ ٨٩ ﻣﻠﻴ ـﻮن ﺳـﻨﺔ ﺿـﻮﺋﻴﺔ ﻣ ـﻦ اﻷرض ، ﰲ ﻛﻮﻛﺒﺔ اﻟﺪﻟﻮ ، ﻫﺬا ﻫﻮ أﻗﺮب زوج ﻣﻦ اﻟﺜﻘﻮب اﻟﺴﻮداء ﻓﺎﺋﻘـﺔ اﻟﻜﺘﻠـﺔ إﻟﻴﻨـﺎ . ﻳﻔـﱰض أن ﻳﻔﺼﻞ ﺑ اﻟﺜﻘﻮب اﻟﺴ ﻮداء ﰲ ا ﺠـﺮة NGC 7727 ﻣﺴﺎﻓﺔ ١٦٠٠ ﺳﻨﺔ ﺿﻮﺋﻴﺔ ﻓﻘﻂ وﻣﻦ ا ﺘﻮﻗﻊ أن ﺗﻨـﺪﻣﺞ ﰲ ﻏﻀـﻮن ٢٥٠ ﻣﻠﻴـﻮن ﺳـﻨﺔ ، ﰲ ﻏﻤﻀـﺔ ﻋـ ﰲ اﻟـﺰﻣﻦ اﻟﻔﻠﻜـﻲ . ﻋﻨﺪﻣﺎ ﺗﻨﺪﻣﺞ اﻟﺜﻘﻮب اﻟﺴﻮداء ﻓﺈﻧﻬﺎ ﺳﺘﺨﻠﻖ ﺛﻘﺒًﺎ أﺳﻮد أﻛﺜـﺮ ﺿـﺨﺎﻣﺔ . ﻣـﻦ ا ﺘﻮﻗـﻊ أن ﻳﺆدي اﻟﺒﺤﺚ ﻋﻦ أزواج ﻣﻦ اﻟﺜﻘﻮب اﻟﺴﻮداء ﻓﺎﺋﻘﺔ اﻟﻜﺘﻠﺔ ﻣﺸﺎﺑﻪ وﻣﺨﻔﻴﺔ ﻗﻔﺰة ﻛﺒ ة إﱃ اﻷﻣﺎم ﻣﻊ اﻟﺘﻠﺴﻜﻮب اﻟﻔﺎﺋﻖ ﻟﻠﻐﺎﻳﺔ اﻟﻘﺎدم و اﻟﺬي ﻣﻦ ا ﻘﺮر أن ﻳﺒﺪأ اﻟﻌﻤﻞ ﰲ وﻗﺖ ﻻﺣـﻖ ﻣﻦ ﻫﺬا اﻟﻌﻘﺪ ﰲ ﺻﺤﺮاء أﺗﺎﻛﺎﻣﺎ ﰲ ﺗﺸـﻴﲇ . وﻣﻌ ـﻪ ﻳﻤﻜﻨﻨ ـﺎ ﺗﻮﻗ ـﻊ ا ﺰﻳ ـﺪ ﻣ ـﻦ ﻫ ـﺬه اﻻﻛﺘﺸﺎﻓﺎت ﰲ ﻣﺮاﻛﺰ ا ﺠﺮات . ﻣﺠﺮﺗﻨﺎ ، اﻟﺘﻲ ﺗﺤﺘـﻮي أﻳﻀًـﺎ ﻋـﲆ ﺛﻘـﺐ أﺳـﻮد ﻫﺎﺋـﻞ ﰲ ﻣﺮﻛ ﺰﻫﺎ ، ﰲ ﻃﺮﻳﻘﻬﺎ ﻟﻼﻧﺪﻣﺎج ﻣﻊ أﻗﺮبﺟﺎر ﻟﻨﺎ ، ﻣﺠﺮة أﻧﺪروﻣﻴﺪا ﺑﻌﺪ ﻣﻠﻴـﺎرات اﻟﺴـﻨ . ﻣﻦ اﻵن رﺑﻤﺎ ﺳﺘﺒﺪو ا ﺠﺮة اﻟﻨﺎﺗﺠﺔ ﺷﺒﻴﻬﺔ ﺑﺎﻟﺮﻗﺼﺔ اﻟﻜﻮﻧﻴﺔ اﻟﺘﻲ ﻧﺮاﻫﺎ ﰲ NGC 7727 ، ﻟﺬﻟﻚ ﻳﻤﻜﻦ أن ﺗﻌﻄﻴﻨﺎ ﻫﺬه اﻟﺼﻮرة ﺤﺔ ﻋﻦ ا ﺴﺘﻘﺒﻞ . ﻣﻨﻈـــــــــــﺮ ﻋـــــــــــﻦ ﻗــــــــــــﺮ ﻟﻨـــــــــــ ﻣﺠــــــــــــﺮ ﺘ ﻮاﺗ ﺳــــــﺎﻃﻌﺘ ــــــﻞ ﻣﻨﻬﻤــــــﺎ ﻋﻠــــــﻰ ﺗﺤﺘــــــﻮي ﺛﻘـــﺐ أﺳـــﻮد ﻓـــﺎﺋﻖ اﻟﻜﺘﻠـــﺔ ، ﻓـــﻲ NGC 7727 . ــــــﻞ ﻧــــــﻮاة ﻣــــــﻦ ﻣ ﻤﻮﻋـــــــﺔ ــــــﻮن ﺗﺘ ﻛﺜ ﻔﺔ ﻣﻦ اﻟﻨﺠﻮم ﻣـﻊ ﺛﻘـﺐ أﺳـﻮد ﻓـﺎﺋﻖ اﻟﻜﺘﻠـــــــــﺔ ﻓـــــــــﻲﻣﺮﻛﺰﻫـــــــــﺎ . ــــــــــﺎن ﻘـــــــــﻊ اﻟﺜﻘ اﻷﺳــــــــــــــﻮدان ﻓـــــــــــــــﻲ ﻣﺴــــــــــــــﺎرﺗﺼـــــــــــــــﺎدﻣﻲ و ﺸـــــــــــــ ﻼن أﻗـــــــــــــﺮ زوج ﻣـــــــــــــﻦ اﻟﺜﻘـــــــــــــﻮب ﺗــﻢ اﻟﻌﺜــﻮرﻋﻠﻴﻬـﺎ اﻟﺴـﻮداء اﻟﻬﺎﺋﻠــﺔ اﻟــ اﻵن ﺣـــــ . ـــــﮫ ﻟﺪ إﻧـــــﮫ أ ﻀًـــــﺎ اﻟـــــﺰوج اﻟـــــﺬ ﺛﻘﺒـــــــــــ أﺻــــــــــﻐﺮ ﻣﺴــــــــــﺎﻓﺔ ﻓﺎﺻـــــــــــﻠﺔ ﺑــــــــــ أﺳــــــــــــﻮدﻳﻦ ﻓـــــــــــــﺎﺋﻘ ﻲ اﻟﻜﺘﻠــــــــــــﺔ ﻟﻮﺣﻈـــــــــــــﺖ اﻟﻤﺴــــــــــﺎﻓﺔ ﺑ ﻨﻬﻤــــــــــﺎ ١٦٠٠ ﺳــــــــــﻨﺔ ﺿــــــــــﻮﺋ ﺔ ﻓﻘﻂﻓﻲ اﻟﺴﻤﺎء . ﻣﺠﻠﺔ Astronomy ﺎﻟﻌﺮ ﺔ ١٩ ﻧﻮﻓﻤ دﻳﺴﻤ 2022