Free Astronomy Magazine November-December 2023 ARABIC VERSION

DECam captures galaxies in lopsided tug of war, a prelude to merger by NOIRLab Charles Blue and Josie Fenske alaxies grow and evolve over billions of years by absorbing nearby companions and merging with other galaxies. The early stages of this galactic growth process are showcased in a new image taken with the US Depart- ment of Energy’s (DOE) Dark Energy Camera (DECam) mounted on the National Science Foundation’s (NSF) Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Ob- servatory (CTIO), a Program of NSF’s NOIRLab The massive barred spiral galaxy NGC 1532, also known as Haley’s Coronet, is located about 55 million light-years away in the direction of the southern constellation Eridanus (the river). Its sweeping spiral arms are seen edge-on from Earth, with the nearer arm dipping downward and the receding arm lurching up- ward as it tugs upon its smaller, dwarf companion galaxy NGC 1531. These gravitationally bound galax- ies will eventually become one, as NGC 1532 completely consumes its smaller companion. Despite its small stature, however, the dwarf galaxy has also been ex- erting a noticeable gravitational in- fluence on its larger companion, distorting one of its spiral arms, which can be seen rising above the galactic plane. Additionally, plumes of gas and dust can be seen between the two galaxies, like a bridge of stellar matter held in place by the compet- ing tidal forces. This interaction has also triggered bursts of star forma- tion within both galaxies. This lopsided cosmic tug of war is a snapshot of how large galaxies grow and evolve by devouring smaller galaxies, absorbing their stars and star-forming material. A similar process has happened in the Milky Way, possibly six times in the past, leaving vast streams of stars and other signs in the halo of the Milky Way. The process of absorbing a smaller companion galaxy is starkly differ- ent from the cataclysmic merger of two spiral galaxies of comparable size. In the latter case, two massive galaxies collide to form an entirely distinct galaxy with its own shape and characteristics. This type of galactic merger will happen to the Milky Way when it field imaging capabilities, gives as- tronomers highly detailed views of these large-scale galactic interac- tions. It also has the remarkable sensitivity, with the help of the 4- meter Blanco telescope, needed to detect faint objects in our Solar Sys- tem and to trace the influence of dark matter on galaxies across the visible Universe. Currently, DECam is used for programs covering a wide range of science.  ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 32 " ﺎم د ﺗﺼﻮر " ﻣﺠﺮات ﻓﻲ ﻣﻌﺮﻛﺔ ﻏ ﻣﺘ ﺎﻓﺌﺔ ﺗﻤﻬ ﺪاً ﻟﻼﻧﺪﻣﺎج : ﻘﻠﻢ ﺷﺎرﻟﺰ ﻠﻮ وﺟﻮزيﻓ ﻨﺴﻜﻲ ﻣﺨﺘ ﻧﻮﻳﺮﻻب ــــ ﺘــ ا ﺠﺮات وﺗﺘﻄﻮر ﻋﲆ ﻣﺪى ﻣﻠﻴﺎرات اﻟﺴﻨ ﻣﻦ ﺧﻼل اﻣﺘﺼﺎص رﻓﺎﻗﻬﺎ اﻟﻘﺮﻳﺒﺔ ﻣﻨﻬﺎ واﻻﻧﺪﻣﺎج ﻣﻊ ا ﺠﺮات اﻷﺧـﺮى . ﻳـﺘﻢ ﻋﺮ ض ا ﺮاﺣﻞ اﻷوﱃ ﻣﻦ ﻋﻤﻠﻴﺔ ﻧﻤﻮ ا ﺠـﺮة ﻫــﺬه ﰲ ﺻــﻮرة ﺟﺪﻳــﺪة ﺗــﻢ اﻟﺘﻘﺎﻃﻬــﺎ ﺑﺎﺳﺘﺨﺪام ﻛﺎﻣ ا اﻟﻄﺎﻗﺔ ا ﻈﻠﻤﺔ ) دي ﻛﺎم ( اﻟﺘﺎﺑﻌﺔ ﻟﻮزارة اﻟﻄﺎﻗﺔ اﻷﻣﺮﻳﻜﻴـﺔ وا ﺜﺒﺘـﺔ ﻋﲆ ﺗﻠﺴﻜﻮب ﻓﻴﻜﺘﻮر إم ﺑﻼﻧﻜـﻮ اﻟﺒـﺎﻟﻎ 4 أﻣﺘﺎر اﻟﺘﺎﺑﻊ ﺆﺳﺴـﺔ اﻟﻌﻠـﻮم اﻟﻮﻃﻨﻴـﺔ ﰲ ﻣﺮﺻﺪ ﺳ و ﺗﻮﻟﻮﻟﻮ ﰲ ﺗﺸـﻴﲇ وﻫـﻮ أﺣـﺪ ﺑﺮاﻣﺞ ﻣﺨﺘـﱪ ﻧـﻮﻳﺮﻻب اﻟﺘـﺎﺑﻊ ﺆﺳﺴـﺔ اﻟﻌﻠﻮم اﻟﻮﻃﻨﻴـﺔ . ﺗﻘـﻊ ا ﺠـﺮة اﻟﺤﻠﺰوﻧﻴـﺔ اﻟﻀﺨﻤﺔ NGC 1532 وا ﻌﺮوﻓﺔ أﻳﻀًﺎ ﺑﺎﺳﻢ ﺗﺎج ﻫﺎﱄ ﻋﲆ ﻣﺴﺎﻓﺔ ﺗﺒﻠﻎ ﺣﻮاﱄ 55 ﻣﻠﻴﻮن ﺳــﻨﺔ ﺿــﻮﺋﻴﺔ ﰲ اﺗﺠــﺎه ﻛﻮﻛﺒــﺔ اﻟﻨﻬــﺮ اﻟﺠﻨﻮﺑﻲ . ﺗُﺮى أذرﻋﻬﺎ اﻟﺤﻠﺰوﻧﻴﺔ ا ﻤﺘﺪة ﻣﻦ اﻟﺤﺎﻓـﺔ ﻣﻦ اﻷرض، ﺣﻴﺚ ﻳﻨﺤﺪر اﻟﺬراع ا ﻷﻗـﺮب إﱃ اﻷﺳﻔﻞ ﺑﻴﻨﻤﺎ ﻳﺘﺠﻪ اﻟـﺬراع ا ﱰاﺟـﻊ ﻧﺤـﻮ اﻷﻋﲆ ﺑﻴﻨﻤﺎ ﻳﺠﺬب ا ﺠﺮة ا ﺮاﻓﻘﺔ اﻷﺻـﻐﺮ ﺣﺠﻤًﺎ NGC 1531 . ﺳﺘﺼﺒﺢ ﻫﺬه ا ﺠﺮات ا ﺮ ﺗﺒﻄﺔ ﺑﺎﻟﺠﺎذﺑﻴـﺔ واﺣﺪة ﰲ اﻟﻨﻬﺎﻳﺔ ﺣﻴﺚ ﺗﺴﺘﻬﻠﻚ NGC 1532 رﻓﻴﻘﺘﻬﺎ اﻷﺻﻐﺮ ﺗﻤﺎﻣ .ﺎً اﻟﻤﺠﺮة اﻟــﺤﻠﺰوﻧ ﺔ NGC 153 واﻟﻤﻌﺮوﻓـﺔ أ ﻀًـﺎ ــﺔﺷــﺪ اﻟـــﺤﺒﻞ ﺎﺳـﻢ ﺗــﺎجﻫــﺎﻟﻲﻋﺎﻟﻘــﺔ ﻓــﻲﻟﻌ ﻏــــــ اﻟﻤﺘﻮاز ــــــﺔ ﻣــــــﻊﺟﺎرﻬــــــﺎ اﻷﺻــــــﻐﺮاﻟﻤﺠــــــﺮة اﻟﻘﺰم NGC 1531 اﻟﺼﻮرة ﻣﻠﺘﻘﻄﺔ ﺑﻮاﺳﻄﺔ ـــــــــﺎﻣ ا اﻟﻄﺎﻗـــــــــﺔ اﻟﻤﻈﻠﻤـــــــــﺔ اﻟﺘﺎ ﻌـــــــــﺔ ﻟـــــــــﻮزارة ـــــــﺔ اﻟﻤﺜ ﺘــــــــﺔ ﻋﻠـــــــﻰﺗﻠﺴــــــــ ﻮب اﻟﻄﺎﻗـــــــﺔ اﻷﻣﺮ ﻜ ــــﺎﻟﻎ اﻟ ــــﻮ اﻟـــﺬ ﻓ ﻜﺘـــﻮرإم ﻼﻧ 4 أﻣﺘـــﺎراﻟﺘــــﺎﺑﻊ ــ ﻟﻤﺆﺳﺴــﺔ اﻟﻌﻠــﻮم اﻟﻮﻃﻨ ﺔ ﻓــﻲﻣﺮﺻــﺪﺳــ و ﺗﻮﻟﻮﻟــﻮ ﻓــﻲﺗﺸــ ﻠﻲ وﻫــﻮ ﺑﺮ ــﺎﻣﺞ ﺗــﺎ ﺑﻊ ﻟﻤﺨﺘــ ـــــــﺔ ﻧــــــﻮرﻻب اﻟﺘــــــﺎﺑﻊ ﻟﻤﺆﺳﺴــــــﺔ اﻟﻌﻠــــــﻮم اﻟﻮﻃﻨ ﻠـــــ ﺘﻘﻂﺗـــــﺄﺛ ات اﻟـــــــﺠﺎذﺑ ﺔ اﻟﻤﺘ ﺎدﻟـــــﺔ ﻻﻧــــــﺪﻣﺎج اﻟﻤﺠﺮات اﻟﻀ ﻤﺔ واﻟﻘﺰﻣﺔ . ﺗﻜﺸﻒ اﻟﺼﻮرة أ ﻀ ﺎً ﻣﻦ اﻟﻤﺴـﺘﻌﺮات ﻋﻦ اﺛﻨ اﻟﻌﻈﻤـﻰﻗـﺮ ﻣﺮﻛـﺰاﻟﻤﺠـﺮة NGC 1532 و ﻼﻫﻤـﺎ (SN 2016ija) و (SN 2016iae) ﺣﺪثﻓﻲﻋﺎم 2016 . ﻋﲆ اﻟـﺮﻏﻢ ﻣـﻦ ﻣﻜﺎﻧﺘﻬـﺎ اﻟﺼـﻐ ة إﻻ أن ا ﺠﺮة اﻟﻘﺰﻣﺔ ﺗﻤﺎرس أﻳﻀ ﺎً اً ﺗـﺄﺛ ﺟﺎذﺑﻴـﺎً ﺎً ﻣﻠﺤﻮﻇ ﻋﲆ رﻓﻴﻘﺘﻬﺎ اﻷ ﻛﱪ إﱃ ﺆدي ﻣﻤﺎ ﻳـ ﺗﺸﻮﻳﻪ أﺣﺪ أذرﻋﻬﺎ اﻟﺤﻠﺰوﻧﻴﺔ واﻟﺘﻲ ﻳﻤﻜـﻦ رؤﻳﺘﻬﺎ وﻫﻲ ﺗﺮﺗﻔﻊ ﻓﻮق ﻣﺴـﺘﻮى ا ﺠـﺮة . ﺑﺎﻹﺿﺎﻓﺔ إﱃ ذﻟﻚ ﻳﻤﻜﻦ رؤﻳـﺔ أﻋﻤـﺪ ة ﻣـﻦ اﻟﻐﺎز واﻟﻐﺒﺎر ﺑ ا ﺠﺮﺗ ـ ﻣﺜﻞ ﺟﺴ ﺮ ﻣـﻦ ا ﺎدة اﻟﻨﺠﻤﻴﺔ اﻟـﺬي ﺗـﻢ ﺗﺜﺒﻴﺘـﻪ ﰲ ﻣﻜﺎﻧـﻪ ﺑ ﻮاﺳﻄﺔ ﻗﻮى ا ﺪ واﻟﺠـﺰر ا ﺘﻨﺎﻓﺴـﺔ وﻗـﺪ أدى ﻫﺬا اﻟﺘ ﻔﺎﻋﻞ أﻳﻀ إﱃ ﺎً إﻃـﻼق رﺷـﻘﺎت ﻧﺎرﻳﺔ ﻣﻦ ﻋﻤﻠﻴﺎت ﺗﻜﻮﻳﻦ اﻟﻨﺠﻮم داﺧﻞ ﻛﻠﺘﺎ ا ﺠﺮﺗ . إن ﻟﻌﺒﺔ ﺷﺪ اﻟﺤﺒﻞ اﻟﻜﻮﻧﻴـﺔ ﻏـ ا ﺘﻮازﻧـﺔ ﻫﺬه ﻫﻲ ﺤﺔ ﴎﻳﻌﺔ ﻟﻜﻴﻔﻴﺔ ﻧﻤﻮ ا ﺠـﺮات اﻟﻜﺒ ة وﺗﻄﻮرﻫ ﺎ ﻣﻦ ﺧﻼل اﻟﺘﻬﺎم ا ﺠﺮات اﻷﺻﻐﺮ واﻣﺘﺼﺎص ﻧﺠﻮﻣﻬـﺎ وا ـﻮاد اﻟﺘـﻲ ﺗﺸﻜﻞ اﻟﻨﺠﻮ . م وﻗﺪ ﺣﺪﺛﺖ ﻋﻤﻠﻴﺔ ﻣﻤﺎﺛﻠﺔ ﰲ ﻣﺠـﺮة درب اﻟﺘﺒﺎﻧـﺔ رﺑﻤـﺎ ﺳـﺖ ﻣـﺮات ﰲ ا ﺎﴈ، ﺗﺎرﻛﺔ ﺗﻴﺎرات ﻫﺎﺋﻠـﺔ ﻣـﻦ اﻟﻨﺠـﻮم وﻋﻼﻣ ـﺎت أﺧ ـﺮى ﰲ ﻫﺎﻟ ـﺔ درب اﻟﺘﺒﺎﻧ ـﺔ . ﺗﺨﺘﻠﻒ ﻋ ﻤﻠﻴﺔ اﻣﺘﺼـﺎص ﻣﺠـﺮة ﻣﺮاﻓﻘـﺔ أﺻﻐﺮ ﺑﺸﻜﻞ ﺻﺎرخ ﻋﻦ اﻻﻧﺪﻣﺎج اﻟﻜـﺎرﺛﻲ ﺠﺮﺗ ﺣﻠﺰوﻧﻴﺘ ﻟﻬﻤﺎ ﻧﻔﺲ اﻟﺤﺠـﻢ وﰲ . اﻟﺤﺎﻟﺔ اﻷﺧ ة، ﺗﺼﻄﺪم ﻣﺠﺮﺗﺎن ﺿﺨﻤﺘﺎن ﻟﺘﺸﻜﻼ ﻣﺠﺮة ﻣﺘﻤﻴﺰة ﺗ ﻤﺎﻣًـﺎ ﻟﻬـﺎ ﺷـﻜﻠﻬﺎ وﺧﺼﺎﺋﺼـﻬﺎ اﻟﺨﺎﺻـﺔ وﻫـﺬا اﻟﻨـﻮع ﻣـﻦ اﻻﻧﺪﻣﺎج ا ﺠﺮي ﺳﻴﺤﺪث ﺠﺮة درب اﻟﺘﺒﺎﻧﺔ ﻋﻨﺪﻣﺎ ﺗﻨﺪﻣﺞ ﻣﻊ ﻣﺠﺮة ا ﺮأة ا ﺴﻠﺴﻠﺔ ﺑﻌﺪ أ رﺑﻌﺔ ﻣﻠﻴﺎ رات ﺳﻨﺔ ﻣﻦ اﻵن . ﺗﻮﻓﺮ ﻛﺎﻣ ا ) دي ﻛـﺎم ( ﺑﻘـﺪراﺗﻬﺎ اﻟﺘـﻲ ﻻ ﻣﺜﻴﻞ ﻟﻬﺎ ﰲ اﻟﺘﺼﻮﻳﺮ واﺳﻊ ا ﺠـﺎل ﻟﻌﻠﻤـﺎء اﻟﻔﻠـﻚ ﻣﺸـﺎﻫﺪات ﻣﻔﺼـﻠﺔ ﻟﻠﻐﺎﻳـﺔ ﻟﻬـﺬه اﻟﺘﻔﺎﻋﻼت ا ﺠﺮﻳﺔ واﺳﻌﺔ اﻟﻨﻄﺎق ﻛﻤﺎ أﻧﻬﺎ ﺗﺘﻤﺘ ـﻊ ﺑﺤﺴﺎﺳـﻴﺔ ﻣﻠﺤﻮﻇــﺔ ﺑﻤﺴــﺎﻋﺪة ﺗﻠﺴﻜﻮب ﺑﻼﻧﻜـﻮ اﻟﺒـﺎﻟﻎ 4 أﻣﺘـﺎر اﻟﻼزﻣـﺔ ﻟﻜﺸــﻒ اﻷﺟﺴــﺎم اﻟﺨﺎﻓﺘــﺔ ﰲ ﻧﻈﺎﻣﻨــﺎ اﻟﺸﻤﴘ وﺗﺘﺒﻊ ﺗﺄﺛ ا ـﺎدة ا ﻈﻠﻤـﺔ ﻋـﲆ ا ﺠﺮات ﻋﱪ اﻟﻜﻮن ا ﺮﺋﻲ . ﺣﺎﻟﻴﺎً ﻳﺘﻢ اﺳﺘﺨﺪام ) دي ﻛﺎم ( ﻟﻠﱪاﻣﺞ اﻟﺘﻲ ﺗﻐﻄﻲ ﻧﻄﺎﻗ ﺎً ﺎً واﺳﻌ ﻣﻦ اﻟﻌﻠﻮم . ﻧﻮﻓﻤﺒﺮ - ﺩﻳﺴﻤﺒﺮ 2 0 2 3 ﺗﻨﻤﻮ