Free Astronomy Magazine January-February 2024 ARABIC VERSION

he swirling arms of a spiral galaxy are among the most recognized features in the cos- mos: long sweeping bands spun off from a central core, each brimming with dust, gas, and dazzling pockets of newly formed stars. Yet this opu- lent figure can warp into a much more bizarre and amorphous shape during a merger with another gal- axy. The same sweeping arms are suddenly perturbed into disarray, and two supermassive black holes at their respective centers become en- tangled in a tidal dance. This is the case of NGC 7727, a peculiar galaxy located in the constellation of Aquarius about 90 million light- years from the Milky Way. Astronomers have captured an evocative image of this merger’s af- termath using the Gemini Multi-Ob- ject Spectrograph (GMOS) mounted on the Gemini South telescope in Chile, part of the International Gem- ini Observatory operated by NSF’s NOIRLab. The image reveals vast swirling bands of interstellar dust and gas resembling freshly-spun cot- ton candy as they wrap around the merging cores of the progenitor galaxies. From the aftermath has emerged a scattered mix of active starburst regions and sedentary dust lanes encircling the system. What is most noteworthy about NGC 7727 is undoubtedly its twin galactic nuclei, each of which houses a supermassive black hole, as con- firmed by astronomers using the Eu- ropean Southern Observatory’s Very Large Telescope (VLT). Astronomers now surmise the galaxy originated as a pair of spiral galaxies that be- came embroiled in a celestial dance about one billion years ago. Stars and nebulae spilled out and were pulled back together at the mercy of the black holes’ gravitational tug-of- war until the irregular tangled knots we see here were created. The two supermassive black holes, one measuring 154 million solar masses and the other 6.3 million solar masses, are approximately 1600 light-years apart. It is esti- mated that the two will eventually merge into one in about 250 million years to form an even more massive black hole while dispersing violent ripples of gravitational waves across spacetime. Because the galaxy is still reeling from the impact, most of the ten- drils we see are ablaze with bright young stars and active stellar nurs- eries. In fact, about 23 objects found in this system are considered candi- dates for young globular clusters. These collections of stars often form in areas where star formation is higher than usual and are especially common in interacting galaxies as we see here. Once the dust has settled, NGC 7727 is predicted to eventually become an elliptical galaxy composed of older stars and very little star formation. Similar to Messier 87, an elliptical galaxy with a supermassive black hole at its heart, this may be the fate of the Milky Way and the Androm- eda Galaxy when they fuse together in billions of years’ time.     JANUARY-FEBRUARY 2024 - ﻳﻨﺎﻳﺮ ﻓﺒﺮﺍﻳﺮ 2 0 2 4 : ﻘﻠﻢ ﺟﻮزي ﻓ ﻨﺴﻜﻲ ﻣﺨﺘ ﻧﻮﻳﺮﻻب ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 27 ﺗﻠﺴـ ﻮب ﺳــﺎوث ــ ﺟ ﻤ ﻫــﻮ أﺣــﺪ ﺗﻠﺴــ ﻮﺑﻲ ﻣﺮﺻـــــــﺪ ـــــــ ﺟ ﻤ ـــــــﺪﻳﺮﻩ اﻟـــــــﺪوﻟﻲ اﻟـــــــﺬ اﻟﻤﺨﺘــــــــ ﻷﺑﺤــــﺎث ﻋﻠـــــﻢ اﻟﻔﻠــــﻚ اﻟ ﺼــــﺮيواﻷﺷـــــﻌﺔ اﻟــــﻮﻃ ﺗﺤـﺖ ا ـﻟـ ) ﻤﺮاء ﻧـﻮﻳﺮﻻب ( اﻟﺘـﺎﺑﻊ ﻟ ﻤﺆﺳﺴـﺔ اﻟﻌﻠـﻮم ــــﺔ اﻟﻮﻃﻨ ﻠــــﺘﻘﻂ آﺛــــﺎراﺻــــﻄﺪام ﻣﺠــــﺮة ــــﺔ ﺣﻠﺰوﻧ ــﺎرﻋــﺎم وﻓــﻲ ﻗﻠــﺐ ﻫــﺬا اﻟﺘﻔﺎﻋــﻞ ﻣﺰدوﺟـﺔ ﻣﻨــﺬ ﻣﻠ اﻟﻔﻮﺿــــــﻮي اﻟﻤﺘﺸــــــﺎ ﻚواﻟﻤﺤﺼــــــﻮر ﻓــــــﻲوﺳــــــﻂ اﻟﻔﻮﺿـﻰ ﻳﻮﺟــﺪ زوج ﻣــﻦ اﻟﺜﻘــﻮب اﻟﺴــﻮداء ﻓﺎﺋﻘــﺔ اﻟﻜﺘﻠــﺔ وﻫــﻮ أﻗــﺮ زوج ﻣــﻦ اﻟﺜﻘــﻮب ـﺘﻢ اﻟﺴــﻮداء ﺗﺴﺠ ﻠﮫ ﻋﻠﻰ اﻹﻃﻼق ﻣﻦ اﻷرض . ﺗﻌـﺪ اﻷذرع اﻟﺪواﻣﺔ ﻟﻠﻤﺠﺮة اﻟﺤﻠﺰوﻧﻴﺔ ﻣـﻦ ﺑ اﻟﺴﻤﺎت اﻷﻛﺜﺮ ﺷﻬﺮة ﰲ اﻟﻜﻮن : أﴍﻃﺔ ﻃﻮﻳﻠﺔ واﺳﻌﺔ ﺗﻨﺒﺜﻖ ﻣﻦ اﻟﻨﻮاة ا ﺮﻛﺰﻳﺔ، ﻛﻞ ﻣﻨﻬﺎ ﻣﲇء ﺑﺎﻟﻐﺒﺎر واﻟﻐﺎز واﻟﺠﻴـﻮب ا ﺒﻬـﺮة ﻣﻦ اﻟﻨﺠﻮم ا ﺘﻜﻮﻧﺔ ﺣﺪﻳﺜ ﺎً وﻣﻊ ذﻟـﻚ ﻳﻤﻜـﻦ ﻟﻬﺬا اﻟﺸﻜﻞ اﻟﻔﺨﻢ أن ﻳﺘﺤﻮل إﱃ ﺷﻜﻞ أﻛﺜـﺮ ﻏﺮاﺑﺔ وﻏ ﻣﺘﺒﻠﻮر أﺛﻨﺎء اﻻﻧﺪﻣﺎج ﻣﻊ ﻣﺠﺮة أﺧــﺮى وﻓﺠــﺄة ﺗﻀــﻄﺮب ﻧﻔــﺲ ا ﻷذرع اﻟﻜﺎﺳﺤﺔ ﰲ ﺣﺎﻟﺔ ﻣـﻦ اﻟﻔـﻮﴇ وﻳﺘﺸـﺎﺑ ﻚ ﺛﻘﺒﺎن أﺳﻮدان ﻫﺎﺋﻼن ﰲ ﻣﺮﻛﺰﻳﻬﻤﺎ ﰲ رﻗﺼﺔ . ﻣﺪﻳﺔ ﻫـﺬه ﻫـﻲ ﺣﺎﻟـﺔ NGC 7727 وﻫـﻲ ﻣﺠﺮة ﻏﺮﻳﺒﺔ ﺗﻘﻊ ﰲ ﻛﻮﻛﺒﺔ اﻟﺪﻟﻮ ﻋـﲆ ﺑﻌـﺪ ﻮاﱄ ﺣـ 90 ﻣﻠﻴـﻮن ﺳـﻨﺔ ﺿـﻮﺋﻴﺔ ﻣـﻦ درب اﻟﺘﺒﺎﻧﺔ . اﻟﺘﻘﻂ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﺻﻮرة ﻣﺜ ة ﻟﻠـﺬﻛﺮﻳﺎت ﻵﺛـﺎر ﻫـﺬا اﻻﻧـﺪﻣﺎج ﺑﺎﺳـﺘﺨﺪام ﻣﻄﻴـﺎف ﺟﻴﻤﻴ ﻨﻲ ﻣﺘﻌﺪد اﻷ ) ﺟﺮام GMOS ( ا ﺜﺒﺖ ﻋﲆ ﺗﻠﺴﻜﻮب ﺟﻴﻤﻴﻨﻲ ﺳﺎوث ﰲ ﺗﺸﻴﲇ وﻫﻮ ﺟﺰء ﻣﻦ ﻣﺮﺻﺪ ﺟﻴﻤﻴﻨﻲ اﻟﺪوﱄ اﻟﺬي ﻳﺪﻳﺮه ﻣﺨﺘﱪ ﻧﻮﻳﺮﻻب اﻟﺘﺎﺑﻊ ﺆﺳﺴـﺔ اﻟﻌﻠـﻮم اﻟﻮﻃﻨﻴـﺔ . ﺗﻜﺸﻒ اﻟﺼﻮرة ﻋﻦ أﴍﻃﺔ دواﻣﻴﺔ واﺳـﻌﺔ ﻣﻦ اﻟﻐﺒﺎر واﻟﻐﺎز اﻟﺒﻴﻨﺠﻤـﻲ ﺗﺸـﺒﻪ ﺣﻠـﻮى اﻟﻘﻄﻦ ا ﻐﺰوﻟﺔ ﺣـﺪﻳﺜ ﺎ وﻫـﻲ ﺗﻠﺘـﻒ ﺣـﻮل اﻟﻨﻮى ا ﻨﺪﻣﺠﺔ ﻟﻠﻤﺠﺮات اﻟﺴﺎﻟﻔﺔ وﻗﺪ ﻇﻬﺮ ﰲ أﻋﻘﺎب ذﻟﻚ ﻣـﺰﻳﺞ ﻣﺘﻔـﺮق ﻣـﻦ ﻣﻨـﺎﻃﻖ اﻻﻧﻔﺠﺎر اﻟﻨﺠﻤﻲ اﻟﻨﺸﻄﺔ وﻣﻤـﺮات اﻟﻐﺒـﺎر ا ﺴﺘﻘﺮة اﻟﺘﻲ ﺗﺤﻴﻂ ﺑﺎﻟﻨﻈﺎم . إن أﻛ ﺜﺮ ﻣﺎ ﻳﻠﻔﺖ اﻻﻧﺘﺒﺎه ﰲ NGC 7727 ﻮ ﻫـ ﺑﻼ ﺷﻚ ﻧﻮاﺗﻬﺎ ا ﺠﺮﻳﺔ اﻟﺘﻮأم اﻟﺘﻲ ﻳ ﺤﺘﻮي ﻛﻞ ﻣﻨﻬﺎ ﻋﲆ ﺛﻘﺐ أﺳﻮد ﻫﺎﺋـﻞ وﻫـﻮ ﻣـﺎ أﻛـﺪه ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﺑﺎﺳـﺘﺨﺪام اﻟﺘﻠﺴـﻜﻮب اﻟ ﻜﺒـ اً ﺟــﺪ اﻟﺘـﺎﺑﻊ ﻟﻠﻤﺮﺻـﺪ اﻟﺠﻨـﻮﺑﻲ اﻷوروﺑـﻲ وﻳﻌﺘﻘﺪ ﻋﻠﻤﺎء اﻟﻔﻠﻚ اﻵن أن ا ﺠـﺮة ﻧﺸـﺄت ﻛﺰوج ﻣﻦ ا ﺠﺮات اﻟﺤﻠﺰوﻧﻴﺔ اﻟﺘﻲ أﺻـﺒﺤﺖ ﻣﺸﺎرﻛﺔ ﰲ رﻗﺼﺔ ﺳﻤﺎوﻳﺔ ﻣﻨﺬ ﺣﻮاﱄ ﻣﻠﻴﺎر . ﺳﻨﺔ اﻧﺴﻜﺒﺖ اﻟﻨﺠﻮم واﻟﺴﺪم وﺗﻢ ﺳـﺤﺒﻬﺎ ﻣﻌﺎً ﻣﺮة أﺧﺮى ﺗﺤﺖ رﺣﻤﺔ ﺷﺪ اﻟﺤﺒﻞ اﻟﺜﻘﺎﱄ ﻟﻠﺜﻘﻮب اﻟﺴـﻮداء ﺣﺘـﻰ ﺗـﻢ إﻧﺸـﺎء اﻟﻌﻘـﺪ ا ﺘﺸﺎ و ﺑﻜﺔ ﻏ ا ﻨﺘﻈﻤﺔ اﻟﺘﻲ ﻧﺮاﻫﺎ ﻫﻨﺎ . اﻟﺜﻘﺒﺎن اﻷﺳـﻮدان اﻟﻬـﺎﺋﻼن أﺣـﺪﻫﻤﺎ ﺗﺒﻠـﻎ ﻛﺘﻠﺘﻪ 154 ﻣﻠﻴﻮن ﻛﺘﻠﺔ ﺷﻤﺴﻴﺔ واﻵﺧﺮ 6.3 ﻣﻠﻴﻮن ﻛﺘﻠﺔ ﺷﻤﺴﻴﺔ وﻳﺒﻌﺪان ﻋﻦ ﺑﻌﻀـﻬﻤﺎ ﺑﺤﻮ اﱄ 1600 . ﺳﻨﺔ ﺿﻮﺋﻴﺔ ﺗﺸ اﻟﺘﻘﺪﻳﺮات إﱃ أن اﻻﺛﻨ ﺳﻴﻨﺪﻣﺠﺎن ﰲ اﻟ ﻨﻬﺎﻳﺔ ﰲ ﺛﻘﺐ أﺳﻮد واﺣﺪ ﺧﻼل ﺣﻮاﱄ 250 ﻣﻠﻴﻮن ﺳﻨﺔ ﻟﻴ ﺸﻜﻞ ﺛﻘﺐ أﺳﻮد أﻛﺜﺮ ﺿﺨﺎﻣﺔ ﺑﻴﻨﻤﺎ ﻳﻨﺜﺮان ﺗﻤﻮﺟﺎت ﻋﻨﻴﻔـﺔ ﻣـﻦ ﻣﻮﺟـﺎت اﻟﺠﺎذﺑﻴﺔ ﻋﱪ اﻟﺰﻣﻜﺎن . ﻧﻈﺮاً ﻷن ا ﺠﺮة ﻻ ﺗﺰال ﺗﻌﺎﻧﻲ ﻣـﻦ اﻟﺼـﺪﻣﺔ ﻓﺈن ﻣﻌﻈﻢ اﻟﺘﻔﺮﻋﺎت اﻟﺬي ﻧ ﺎ ﺮاﻫـ ﺔ ﻣﺸـﺘﻌﻠ ﺑﻨﺠ ﻮم ﺷﺎﺑﺔ ﻻﻣﻌﺔ وﺣ ﺿﺎ ﻨﺔ ﻧﺠﻤﻴﺔ ﻧﺸـﻄﺔ ﰲ اﻟﻮاﻗﻊ ﻫﻨﺎك ﺣﻮاﱄ 23 ﺟﺴﻤﺎً ﰲ اً ﻣﻮﺟـﻮد ﻫﺬا اﻟﻨﻈﺎم ﺗﻌﺘﱪ ﻣﺮﺷﺤﺔ ﻟ ﻌﻨﺎﻗﻴـﺪ ﻛﺮوﻳـﺔ ﺎً ﻏﺎﻟﺒ و ﺷﺎﺑﺔ ﻣﺎ ﺗﺘﺸﻜﻞ ﻫﺬه ا ﺠﻤﻮﻋﺎت ﻣﻦ اﻟﻨﺠﻮم ﰲ ا ﻨﺎﻃﻖ اﻟﺘﻲ ﻳﻜﻮن ﻓﻴﻬـﺎ ﺗﻜـﻮﻳﻦ اﻟﻨﺠﻮم أﻋﲆ ﻣﻦ ا ﻌﺘﺎد وﻫﻲ ﺷﺎﺋﻌﺔ ﺗﺤﺪﻳﺪاً ﰲ ا ﺠ ﺮات ا ﺘﻔﺎﻋﻠﺔ ﻛﻤﺎ ﻧﺮى ﻫﻨﺎ . ﻋﻨﺪ اﺳﺘﻘﺮار اﻟﻐﺒﺎر ﻳﺘﻮﻗﻊ أن ﺗﺼـﺒﺢ NGC 7727 اﻟﰲ ﻨﻬﺎﻳﺔ ﻣﺠﺮة إﻫﻠﻴﻠﺠﻴﺔ ﺗﺘﻜﻮن ﻣﻦ ﻧﺠ ﻮم أﻗﺪم وﺗﻜﻮﻳﻦ ﻧﺠﻤﻲ ﻗﻠﻴﻞ ﺟﺪاً . ا ﻣﺜﻞ اﻟ ﺠﺮة ﺒﻴﻀﺎوﻳﺔ م) 87( اﻟﺘـﻲ ﺗﺤﺘـﻮي ﺛﻘﺐ أﺳﻮد ﻫﺎﺋﻞ ﻗﺪ ﻳﻜﻮن ﻫـﺬا ﻫـﻮ ﻣﺼـ ﻣﺠﺮة درب اﻟﺘﺒﺎﻧﺔ وﻣﺠﺮة ا ـﺮأة ا ﺴﻠﺴـﻠﺔ ﺑﻌﺪ اﻧﺪﻣﺎﺟﻬﺎ ﺑﻌﺪ ﻣﻠﻴﺎرات اﻟﺴﻨ . [Interna-tionalGemini Observatory/NOIRLab/ NSF/AURA. Acknowledgment: PI:C. Onken (Australian NationalUniver- sity). Image processing: T.A. Rector (University of Alaska Anchorage/ NSF’s NOIRLab), J. Miller (Interna- tional Gemini Observatory/NSF’s NOIRLab), M. Rodriguez (Interna- tionalGemini Observatory/NSF’s NOIRLab), M. Zamani (NSF’s NOIRLab)]