Astronomers have discovered the sleeping and waking galaxy


28/06/2011

Astronomers have studied the remote regions of the universe and discovered that galaxies exhibit one of two types of behavior: they are either awake or asleep. Or actively forming stars or do not form new zvezd.Uchenye for years were aware of the fact that the galaxies are located relatively close to us, come to one of these two categories. A new study distant regions of the universe shows that even very young galaxies at a distance of 12 billion light-years, is also asleep or awake. This means that such behavior is typical of galaxies within more than 85 percent of the history of the universe, because when we look at distant galaxies, we see them in the past, due to the fact that light takes time to reach the Earth. "The fact What we see sleeping young galaxies in the distant universe, is very remarkable, "- said Kate Whitaker, a graduate of Yale University and lead author of the study, which was published in the journal Astrophysical Journal.Chtoby determine which of these states is a galaxy, Whitaker and his colleagues produced a set of filters, each of which is sensitive to its portion of the light spectrum. These filters are applied on a four-telescope on Kitt Peak in the Sonoran Desert, Arizona. Over 75 nights, they studied the remote regions of the universe and collected light from 40,000 galaxies, among whom were both located in the neighborhood, and are at a distance of 12 billion light years. The study is the deepest and most complete ever made at those distances and wavelengths sveta.omanda defined type galaxies dual behavior based on the color characteristics of the light they emit. Because of the physics of star formation, active galactic awake look bluer, while the light is passive, sleeping galaxies tends toward the red end spektra.Issledovateli found that active galaxies are much more than passive. This is consistent with the prevailing view today, according to which the first galaxies are actively forming stars, and then the process stops. "We did not see many galaxies in the intermediate state," - said Peter van Dokkum, Yale astronomer and co-author of the article. "This discovery shows how quickly galaxies go from one state to the other, from actively forming stars to complete lull." Wake up to the sleeping galaxies, or remain in this state forever, is still questionable. "We hope to find out whether the alternate periods of sleep and wakefulness or galaxies falling into hibernation they will never wake up," - said van Dokkum. "Also, there remains the question of how long it takes the galaxy to fall asleep, and whether we can detect the galaxy, which is in the process of falling asleep" Original: Physorg


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