* Astronomy

An international team of physicists, including University of Oregon scientists, has concluded that last February's intense burst of gamma rays possibly coming from the Andromeda Galaxy lacked a gravitational wave. That absence, they say, rules out an initial interpretation that the burst came from merging neutron stars or black holes within Andromeda.
A revised interpretation, presented last month by the UO's Isabel Leonor at the 12th Gravitational Wave Data Analysis Workshop in Cambridge, Mass., suggests two possible origins: A merger event beyond Andromeda or a burst from an astronomical object known as a soft gamma-ray repeater within Andromeda. The latter, also called a magnetar, involves neutron stars with enormous magnetic fields that occasionally produce big outbursts of gamma rays.
The new findings are based on a collaborative analysis by the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration, a project funded by the National Science Foundation. LIGO was designed and is operated by the California Institute of Technology and the Massachusetts Institute of Technology for the detection of cosmic gravitational waves and for the development of gravitational wave observations as an astronomical tool.
Leonor, a research associate in the experimental relativity group of the UO's Centre for High Energy Physics, and colleague Ray Frey, a professor of physics, initiated the study during a discussion of the event, known as GRB070201, at a meeting in Louisiana in March. The UO's experimental relativity group is part of the LIGO Scientific Collaboration.

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