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Science 4 January 1985:
Vol. 227. no. 4682, pp. 28 - 31
DOI: 10.1126/science.227.4682.28
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Articles

Discovery of New Variable Radio Sources in the Nucleus of the Nearby Galaxy Messier 82

Philipp P. Kronberg 1 and Richard A. Sramek 2

1 Department of Astronomy and Scarborough College, University of Toronto, Toronto, Ontario, Canada M5S 1A1.
2 National Radio Astronomy Observatory, Socorro, New Mexico 87801.

Widespread variability has been discovered in a large population of radio sources close to the nucleus of an active galaxy. The galaxy, Messier 82 (M82), and others similar to it show evidence for enhanced nuclear activity and unusually strong far-infrared emission. The observational data, obtained with the National Radio Astronomy Observatory's Very Large Array in New Mexico over the past 3 years, provide the first direct "look" at a starburst—the phenomenon of sudden, rapid star formation which occurs near the nucleus of a small fraction of galaxies. Nearly all the brightest of about 40 radio sources in M82' s nucleus decreased in intensity over 2.7 years up to October 1983. One source, which in February 1981 was ten times as bright as our Galaxy's most luminous supernova remnant, turned off within only a few months. Most of the other ten strongest sources are declining so rapidly that they will fade into the background within 30 years. Thus, new supernovae are expected to appear in M82' s nucleus every few years. The discovery has revealed the "engine room" of the mysterious activity in M82 and, by implication, similar active galaxies which have disturbed nuclei and which are unusually luminous in the far infrared. An estimate of the rate of energy input by the radio-visible supernovae closely matches the far-infrared luminosities which were recently measured for M82 and other similar galaxies.

Submitted on October 23, 1984
Accepted on November 13, 1984


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
The Galactic Center: Is It a Massive Black Hole?.
K. Y. Lo (1986)
Science 233, 1394-1403
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