\nsome interesting astrophysical observations. Two teams from different
\ncontinents have found supernovae that have an anomalous
\nfeature: matter is moving away from them at significant fractions of the
\nspeed of light—0.60c and 0.86c. The well known explosion dynamics of a supernova shouldn’t produce that sort of acceleration; in a typical supernova event, matter shouldn’t reach velocities much
\nbeyond three percent the speed of light.<\/p>\n
Speeds this great are often associated with gamma ray bursts, but these observations were missing that key component.
\n“In every respect, these objects look like gamma-ray bursts—except
\nthat they produced no gamma rays,” said Alicia Soderberg, lead author
\nof one of the papers. Her team examined SN
\n2009bb, a supernova in the spiral galaxy NGC 3278, nearly 130 million
\nlight years from Earth. The other team examined SN 2007gr, a supernova in spiral galaxy NGC
\n1058, a scant 35 million light years from Earth.<\/p>\n
Using NASA records of known gamma ray bursts, the teams
\nattempted to find an event that had a spatial and temporal correlation with the supernovae, but none was
\nidentified. Typical gamma ray bursts are thought to be the result of
\nthe acceleration of matter by a black hole, with the matter reaching nearly 99 percent the speed of light. The fast-moving matter here suggests that these supernovae are powered in part by a nascent black
\nhole at the center left behind after the core collapse.<\/p>\n
Casting a wider net for nearby supernovae suggest that these
\n‘central engine’ driven type Ib\/c supernovae are fairly rare, only
\naccounting for about one percent of all cases. However, the work
\nprovides a new tool for astronomers to be able to detect them in the future. “These observations are the first to show some
\nsupernovae are powered
\nby a central engine,” Soderberg said. “These new radio techniques now
\ngive us a way to find explosions that resemble gamma-ray bursts without
\nrelying on detections from gamma-ray satellites.”<\/p>\n
Nature<\/span>,
\n2010. DOI: 10.1038\/nature08714<\/a>
\nNature<\/span>,
\n2010. DOI: 10.1038\/nature08713<\/a>\n<\/p>\n