A survey of our galaxy's center has turned up evidence of what may be a new class of astronomical object. According to results published today in the journal Nature, scientists have detected an unusual burst of radio waves emanating from near the galactic center with characteristics that are unlike those of previously detected radio bursts.

Scott Hyman of Sweet Briar College and his colleagues analyzed data collected from years of monitoring the center of the Milky Way galaxy using the Very Large Array telescope in New Mexico. Radio waves having wavelengths around one meter long were of particular interest to the team: between September 30 and October 1, 2002, they detected five bursts of such radiation, which repeated at regular intervals. The bursts coming from the new source, dubbed GCRT J1745-3009, each lasted about 10 minutes and repeated on a 77-minute cycle for nearly seven hours. In addition, the source is not stationary. "It [GCRT J1745-3009] has not been detected since 2002," Hyman notes, "nor is it present on earlier images."

The transitory nature of GCRT J1745-3009 has made it difficult to assign it to an existing class of object. Whatever it is, it is unique: the astronomers suggest it is either the first of a new type of object or an example of a known source acting in a novel way. Of interest to the scientists is the fact that no x-rays were detected along with the radio waves, because many astronomical sources emit both. In the future, the team plans to continue monitoring the Milky Way for further evidence of GCRT J1745-3009 using both radio and x-ray telescopes. In an accompanying commentary, Shri R. Kulkarni and E. Sterl Phinney of the California Institute of Technology note that "the manner of its discovery, and the potentially exciting interpretation, will inspire more dedicated searches for radio transients."