The merger of two galaxies, known as NGC 7752 (larger) and NGC 7753 (smaller), also collectively called Arp86. It is composed of images from three Spitzer Infrared Array Camera (IRAC) channels. Image credit: NASA/JPL-Caltech
Three images from NASA’s Spitzer Space Telescope show pairs of galaxies on the cusp of cosmic consolidations. Though the galaxies appear separate now, gravity is pulling them together, and soon they will combine to form new, merged galaxies. Some merged galaxies will experience billions of years of growth. For others, however, the merger will kick off processes that eventually halt star formation, dooming the galaxies to wither prematurely.
Only a few percent of galaxies in the nearby universe are merging, but galaxy mergers were more common between six billion and 10 billion years ago, and these processes profoundly shaped our modern galactic landscape. For more than 10 years, scientists working on the Great Observatories All-sky LIRG Survey, or GOALS, have been using nearby galaxies to study the details of galaxy mergers and to use them as local laboratories for that earlier period in the universe’s history. The survey has focused on 200 nearby objects, including many galaxies in various stages of merging.
In these images, ...