Free Astronomy Magazine July-August 2022 ARABIC VERSION

T his impressive image shows the strangely lopsided spiral gal- axy NGC 772, which lies over 100 million light-years from Earth in the constellation Aries. Captured by the Gemini North telescope in Hawai’i, one half of the interna- tional Gemini Observatory, a Pro- gram of NSF’s NOIRLab, the image shows NGC 772’s overdeveloped spi- ral arm, which stretches across to- ward the left-hand edge of the frame. This extra large arm is due to one of NGC 772’s unruly neighbors, the dwarf elliptical galaxy NGC 770. The tidal interactions between NGC 772 and its diminutive companion have distorted and stretched one of the spiral galaxy’s arms, giving it the lopsided appearance seen in this image. NGC 772 also lacks a bright central bar. Other spiral galaxies such as the Andromeda Galaxy or our own Milky Way exhibit promi- nent central bars — large, linear structures composed of gas, dust, and countless stars. Without a bar, NGC 772’s spiral arms sweep out di- rectly from the bright center of the galaxy. The galaxy’s unusual appear- ance has earned it the distinction of appearing in the Atlas of Peculiar Galaxies, a careful curation by as- tronomer Halton Arp of some of the weird and wonderful galaxies popu- lating the Universe. The 338 galaxies in the Atlas are a rogues’ gallery of strange and unusual galaxy shapes chosen to provide astronomers with a catalog of odd galaxy structures. Entries in the Atlas of Peculiar Galax- ies include galaxies boasting trailing tidal tails, rings, jets, detached seg- ments, and a host of other structural idiosyncrasies. NGC 772 is included as Arp 78. While NGC 772’s peculiarities dominate this image, there is also a menagerie of galaxies lurking in the background. The bright smears and smudges littering this image are dis- tant galaxies — some of the closer examples can be resolved into char- acteristic spiral shapes. Every direc- tion on the sky that astronomers have pointed telescopes toward con- tains a rich carpet of galaxies, with an estimated 2 trillion galaxies in total in our observable Universe.      ذراع ﻣﺠﺮي ﻛﺒ ﺟﺪًا : ﻘﻠﻢ اﻣﺎﻧﺪا ﻮﺗﺶ اﻟ ﻟﺒﺤـﻮث اﻟﻔﻠـﻚ ﺎﻷﺷـﻌﺔ ﺗﺤـﺖ ﻤﺨﺘ اﻟﻮﻃ ا ﻤﺮاء اﻟﻀﻮﺋ ﺔ ) NOIRLab ( ﺗُﻈﻬـﺮ ﻫـﺬه اﻟﺼـﻮرة اﻟﺮاﺋﻌـﺔ اﳌﺠـﺮة اﳊﻠﺰوﻧﻴـﺔ ﻏـﲑ اﳌﺘﻮازﻧـﺔ ﺑﺸـﻜﻞ ﻏﺮﻳـﺐ NGC 772 واﻟـﱵ ﺗ ﺒﻌــﺪ أﻛــﱶ ﻣــﻦ ١٠٠ ﻣﻠﻴــﻮن ﺳــﻨﺔ ﺿــﻮﺋﻴﺔ ﻋــﻦ اﻷرض ﺑﺎﺗﺠــــﺎه ﻛﻮﻛﺒــــﺔ اﳊﻤــــﻞ ﰎ. اﻟﺘﻘـــــﺎط اﻟﺼﻮرة ﺑﻮاﺳﻄﺔ ﺗﻠﺴﻜﻮب ﻧـﻮرث ﺟﻴﻤﻴـﲏ ﻫﺎواي وﻫـﻮ ﻣـﻦ ﺟـﺰء ﻣﺮﺻـﺪ ﺟﻴﻤﻴـﲏ اﻟـﺪوﱄ وﻫﻮ ﺑﺮﻧﺎﱅ ﻣﻦ اﳌﺨﺘـﱪ اﻟـﻮﻃﲏ ﻟﺒﺤـﻮث اﻟﻔﻠـﻚ ﺑﺎﻷﺷﻌﺔ ﺗﺤﺖ اﳊ اء اﻷﻣﺮﻳﲄ (NOIRLab) اﻟﺘـﺎﺑﻊ ﻟ ﻠﻤﺆ ﺳﺴـﺔ اﻟﻮﻃﻨﻴـﺔ ﻟﻠﻌﻠـﻮم (NSF) وﺗُﻈﻬِـــﺮ اﻟﺼـــﻮرة اﻟـــﺬراع اﳊﻠﺰوﻧﻴـــﺔ اﻟﻬﺎﺋﻠـــﺔ ﻟﻠﻤﺠـﺮة NGC 772 واﻟـﺬي ﳝﺘــﺪ إﱃ اﳉﺎﻧـﺐ اﻷﻳﴪــ ﺣﺎﻓــﺔ اﻹﻃــﺎر ، ﻫــﺬه اﻟــﺬراع اﻟﻜﺒــﲑة ﺗﺮﺟــﻊ إﱃ إﺣــﺪى اﳉــﺎرات ﳌ ﺠــﺮة NGC 772 وﻫـﻲ اﳌﺠـﺮة اﻹﻫﻠﻴﻠﺠﻴـﺔ اﻟﻘﺰﻣـﺔ NGC 770 ﻟﻘـﺪ أدت ﺗﻔـﺎﻋﻼت اﳌـﺪ واﳉـﺰر ﺑـﲔ NGC 772 ﻬــﺎ ﺘ ورﻓﻴﻘ اﻟﺼــﻐﲑة إﱃ ﺗﺸــﻮﻳﻪ وﲤ ﺪﻳــﺪ أﺣــﺪ أذرع اﳌﺠﺮة اﳊﻠﺰوﻧﻴـﺔ ﳑـﺎ ﻳﻌﻄﻴﻬـﺎ اﳌﻈﻬـﺮ ﻏـﲑ ا ﳌﺘـﻮازن اﻟــﺬي ﻧـﺮاه ﻫـﺬه اﻟﺼـﻮرة ﻟ ﻠﻤﺠــﺮة ــــــ ﺗﻔﺘﻘــﺮ اﳌﺠــﺮة NGC 772 أﻳﻀًــﺎ إﱃﴍﻳــﻂ ﻣﺮﻛــﺰي ﻻﻣــﻊ ، ﺣــﲔ اﳌﺠــﺮات اﳊﻠﺰوﻧﻴــﺔ اﻷﺧــﺮى ﻣﺜــﻞ ﳎــﺮة اﳌــﺮأة اﳌﺴﻠﺴــﻠﺔ أو ﳎﺮﺗﻨــﺎ درب اﻟﺘﺒﺎﻧـــﺔ ﺗﻮﺟـــﺪ أﴍﻃـــﺔ ﻣﺮﻛﺰﻳـــﺔ ﺑـــﺎرزة ﻋﺒــﺎرة ﻋـﻦ ﻫﻴﺎﻛـﻞ ﺧﻄﻴـﺔ ﻛﺒـﲑة ﺗﺘﻜـﻮن ﻣــﻦ اﻟﻐـــﺎز واﻟﻐﺒـــﺎ ر وﻧﺠـــﻮم ﻻ ﺣﴫـــ ﻟﻬـــﺎ ﺑـــﺪون و اﻟﴩــﻳﻂ اﳌﺮﻛـــﺰي ﺗﻜﺘﺴـــﺢ اﻷذرع اﳊﻠﺰوﻧﻴـــﺔ ﳌﺠـﺮة NGC 772 ﻣﺒـﺎﴍة ﻣـﻦ اﳌﺮﻛـﺰ اﳌﴩـق ﻟﻠﻤﺠـﺮة . ﻟﻘـﺪ ان اﳌﻈﻬـﺮ ﻏـﲑ اﻟﻌـﺎدي ﻟﻠﻤﺠـﺮة أﻛﺴـــﺒﻬﺎ ﲤـــﲒًا ﺑـــﺎﻟﻈﻬﻮر أﻃﻠـــﺲ اﳌﺠـــﺮات اﻟﻐﺮﻳﺒﺔ ، وﻫﻮ ﻋﻤﻞ دﻗﻴﻖ ﺑﻮاﺳﻄﺔ ﻋـﺎﱂ اﻟﻔﻠـﻚ ﻫﺎﻟﺘﻮن آرب ﻟﺒﻌﺾ اﳌﺠـﺮات اﻟﻐﺮﻳﺒـﺔ واﻟﺮا ﺋﻌـﺔ اﳌﻨ ﴩة اﻟﻜﻮن . اﳌﺠﺮات اﻟ ﺒﺎﻟﻎ ﻋﺪدﻫﺎ ٣٣٨ اﻷﻃﻠـﺲﻫـﻲ ﻋﺒـﺎرة ﻋـﻦ ﻣﻌـﺮض ﻷﺷـﻜﺎل ﳎـﺮات ﻏﺮﻳﺒـﺔ وﻏــﲑ ﻋﺎدﻳـﺔ ﰎ اﺧﺘﻴﺎرﻫـﺎ ﻟﱱوﻳـﺪ ﻋﻠﻤــــﺎء اﻟﻔﻠــــﻚ ﺑﻔﻬــــﺮس ﻟ ﻬﻴﺎﻛــــﻞ اﳌﺠــــﺮات اﻟﻔﺮدﻳﺔ ﺸﻤﻞ ﻳ. أﻃﻠﺲ اﳌﺠﺮات اﻟﻐﺮﻳﺒﺔ ﳎﺮات ﺗﺘﻤــﲒ ﺑــﺬﻳﻮل اﳌــ ﺪ واﳉــﺰر وﺣﻠﻘــﺎت وﻧﻔﺎﺛــﺎت وأﺟـــﺰاء ﻣﻨﻔﺼـــﻠﺔ وﳎﻤ ﻮ ﻋـــﺔ ﻣـــﻦ اﳋﺼـــﺎﺋﺺ اﻟﻬﻴﻜﻠﻴـــﺔ اﻷﺧـــﺮى ، ﺑﻴﻨﻤـــﺎ ﺗﻬـــﻴﻤﻦ ﺧﺼـــﺎﺋﺺ NGC 772 ﻋــﲆ ﻫـﺬه اﻟﺼـﻮرة ، ﻫﻨـﺎك أﻳﻀًــﺎ ﳎﻤﻮﻋــﺔ ﻣــﻦ اﳌﺠــﺮات اﻟﻜﺎﻣﻨــﺔ اﳋﻠﻔﻴــﺔ . إن اﻟﻠﻄﺨﺎت اﻟﺴﺎﻃﻌﺔ اﳌﺘﻨﺎﺛﺮة ﻫﺬه اﻟﺼـﻮرة ﻫــﻲ ﳎــﺮات ﻣﺘﻔﺮﻗــﺔ ﳝﻜــﻦ و ﻣﻼﺣﻈــﺔ ﺑﻌــﺾ اﻷﻣﺜﻠـﺔ اﻷﻗـ ﺮب إﱃ أﺷـﻜﺎل ﺣﻠﺰوﻧﻴـﺔ ﳑـﲒة ﻛــــﻞ اﺗﺠــــﺎه اﻟﺴــــ ﻤﺎء وﺟــــﻪ اﻟﻔﻠﻜﻴــــﻮن اﻟﺘﻠﺴﻜﻮﺑﺎت ﺑﺎﺗﺠﺎﻫﻪ وﺟـﺪ اﻧـﻪ ﺑـ ﻏـﲏ ﺎﳌﺠﺮات اﳌﺘﻨﻮﻋـــﺔ ﺣﻴـــﺚ ﺗﺸـــﲑ اﻟﺘﻘـــﺪﻳﺮات إﱃ وﺟـــﻮد ﺣﻮاﱄ ٢ ﺗﺮﻳﻠﻴﻮن ﳎﺮة ﻛﻮﻧﻨﺎ اﳌﺮﰄ . إن اﻟﺬراع ا ﻠﺰوﻧ ﺔ اﻟﻤﻤﺘـﺪ إﻟـﻰﺧـﺎرج اﻟﻤﺠـﺮة NGC 772) ( واﻟ ﺗﺸ ﻠ ﺖ ﻣﻦﺧﻼل ﺗﻔﺎﻋﻼت اﻟﻤﺪ وا ﺰرﻣﻊ ﻣﺠﺮة ﺟـﺎرة ﺗﻬـ ﻤﻦ ﻋﻠـﻰﻫـﺬا اﻟﺮﺻـﺪ اﻟــ ﺬ ـﮫ ﻋﻠﻤـﺎء اﻟﻔﻠــﻚ ﺎﺳـﺘﺨﺪام ﻗـﺎم ــﺎﻟﻘﺮ ﻣـﻦ اﻟﻤﻮﺟــﻮد ـ ﺗﻠﺴـ ﻮب ﻧـﻮر ﺟ ﻤ ﻗﻤﺔ ﺟﺒﻞ ﻣﻮﻧﺎ ﻛ ﺎ . [International Gemini Observatory/NOIRLab/NSF/ AURA. Image processing: T.A. Rector (University of Alaska Anchorage),J. Miller (Gemini Observatory/NSF’s NOIRLab), M. Zamani & D. de Martin] ٢٠ 20