Did supernovas pop top off galaxy?Did supernovas pop top off galaxy? For decades, scientists have wondered what could make the unusual galaxy m82 look so spectacular. Its polar caps seem to be blown off, and hot filaments of gas stream forth from those regions. In 1963, astronomers proposed that a giant explosion in the center of the galaxy caused the unusual formation. However, there are no good proposals for how such an explosion would take place, according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. R. Brent Tully R. Brent Tully is an astronomer at the Institute for Astronomy in Honolulu, Hawaii. Tully's specialty is astrophysics of galaxies. He, along with J. Richard Fisher, proposed the now-famous Tully-Fisher relation in a paper, of the University of Hawaii's Institute for Astronomy The Institute for Astronomy (IfA) is a research unit within the University of Hawaii system, led by Dr. Rolf-Peter Kudritzki as Director. IfA main headquarters are located at 2680 Woodlawn Drive in Honolulu, Hawaii; additional facilities are located at Kula, Maui and Hilo on the in Honolulu. Tully and colleague Jonathan Bland propose a somewhat different history for the galaxy in the July 7 NATURE. They suggest galactic gas was blown off not by a huge explosion of a type previously unknown, but rather by many smaller explosions of the more familiar supernova supernova, a massive star in the latter stages of stellar evolution that suddenly contracts and then explodes, increasing its energy output as much as a billionfold. type. Part of the evidence they cite for this is that the gas coming out of the galaxy keeps accelerating as it gets farther from the galactic center -- something that would happen only if explosive activity is still going on and pushing at the gas as it leaves. M82 may contain many more supernovas than usual because the galaxy recently (in astronomical terms) had a close encounter with the nearby galaxy M81, which probably stirred up M82 and lead to a burst of star formation, Tully says. Many of the larger stars formed would pass quickly through their life cycles and become supernovas, he adds. At first, the supernovas "blew off the caps" of the galaxy; later explosions have created a "galactic wind" that keeps blowing gas Noun 1. blowing gas - the gas leaving a generator during a blow period blow gas gas - a fluid in the gaseous state having neither independent shape nor volume and being able to expand indefinitely out of the galaxy, Tully says. As additional evidence for this, he and Bland point out that radiotelescopes have spotted more supernova remnants List of bright supernovas Name Visible Magnitude distance Type Remnant Sagittarius A East ? ? 26,000 ly ? Sagittarius A East W49B ? ? 35,000 ly ? GRB remnant? W50 ? ? 16,000 ly ? SS 433 Vela Supernova 11th-9th millennium BC ? 800 ly ? Vela Supernova Remnant in M82's galactic center than might be expected. The new theoy has wider significance. Supernova activity has long been proposed as the mechanism for keeping elliptical galaxies free of interstellar in·ter·stel·lar adj. Between or among the stars: interstellar gases. interstellar Adjective between or among stars Adj. 1. gas, but such a mechanism has been "rather speculative," Tully says. Although M82 is not an elliptical galaxy, it makes a good cause for such a mechanism, he says. |
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