JPL: Why Do Some Galactic Unions Lead to Doom?
Posted: Wed Feb 27, 2019 9:03 pm
Why Do Some Galactic Unions Lead to Doom?
NASA | JPL-Caltech | Spitzer | 2019 Feb 27
NASA | JPL-Caltech | Spitzer | 2019 Feb 27
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 6 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. The images above show three of those targets, imaged by Spitzer.
In these images, different colors correspond to different wavelengths of infrared light, which are not visible to the human eye. Blue corresponds to 3.6 microns, and green corresponds to 4.5 microns — both strongly emitted by stars. Red corresponds to 8.0 microns, a wavelength mostly emitted by dust. ...