Astronomers have captured a spectacular, ongoing collision between at least three galaxy clusters.
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Data from NASA's Chandra X-ray Observatory, ESA's (European Space Agency's) XMM-Newton, and a trio of radio telescopes is helping astronomers sort out what is happening in this jumbled scene.
Collisions and mergers like this are the main way that galaxy clusters can grow into the gigantic cosmic edifices seen today. These also act as the largest particle accelerators in the universe.
Astronomers have captured a spectacular, ongoing collision between at least three galaxy clusters. Data from NASA's Chandra X-ray Observatory, ESA's (European Space Agency's) XMM-Newton, and a trio of radio telescopes is helping astronomers sort out what is happening in this jumbled scene.
Collisions and mergers like this are the main way that galaxy clusters can grow into the gigantic cosmic edifices seen today. These also act as the largest particle accelerators in the universe.
Radio waves are also coming from huge filamentary structures (labeled "relic"), mostly located to the north of the radio-emitting galaxies, likely generated when the collision created shock waves and accelerated particles in the gas across over two million light-years.
A paper analyzing this structure was published earlier this year by Kamlesh Rajpurohit from the University of Bologna in Italy in the March 2022 issue of The Astrophysical Journal.
This is Paper I in an ongoing series studying different aspects of this colliding galaxy cluster system.
Finally, there is a "halo" of radio emission located near the center of the collision. Because this halo overlaps with the X-ray emission and is dimmer than the filamentary structure and the galaxies, another radio image has been produced to emphasize the faint radio emission.
Paper II led by Rajpurohit, recently published in the journal Astronomy and Astrophysics, presents a model that the halo emission may be caused by the reacceleration of particles by rapid changes in the temperature and density of the gas as the collision and merging of the clusters proceed.
This model, however, is unable to explain all the features of the radio data, highlighting the need for more theoretical study of this and similar objects. ■