University of Wisconsin–Milwaukee

Laura L. Hunt

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Nov 8, 2010 
UWM physicist awarded two prestigious grants
Xavier Siemens
Xavier Siemens

Xavier Siemens, a physicist at the University of Wisconsin–Milwaukee (UWM), has been awarded two prestigious grants from the National Science Foundation (NSF), both related to his work in the international effort to detect gravitational waves.

Siemens, an assistant professor, will use the $500,000 Early Career Development (CAREER) Award to search for evidence of gravitational waves in data from the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the U.S., and VIRGO and GEO in Europe, as well as signals from pulsars in data collected from radio telescopes such as the Arecibo Radio Telescope in Puerto Rico.

Gravitational waves are ripples in space-time produced when massive objects in space move violently. The direct detection of gravitational waves will simultaneously test our understanding of fundamental physics and provide a new means to study the universe.

A major component of the CAREER grant involves the use of Einstein@Home, which Siemens helped to develop and maintains at UWM. Einstein@Home is a computer-sharing initiative that harnesses idle time from the computers of volunteers around the world to search for gravitational waves in the massive amount of data from LIGO detectors, and also for undiscovered pulsars in radio observatory data.

The project will bring together a diverse group of undergraduates, graduate students and senior personnel to participate in the collection and analysis of the various data at UWM.

Siemens also is a senior investigator on a $6.5 million grant from NSF’s Partnerships for International Research and Education (PIRE) that will support an international consortium of researchers and students who are using observations of millisecond pulsars – highly accurate celestial clocks – to detect gravitational waves.
Members of the consortium, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), will use radio telescopes around the world to observe signals from dozens of pulsars over several years. This will allow them to directly test for the existence of gravitational waves and, after detection, identify and characterize their astrophysical sources.

Siemens is the eighth member of UWM’s Department of Physics to receive a CAREER Award, the NSF’s most highly regarded grant for younger researchers. It supports the career development of teacher-scholars who are most likely to become the academic leaders of this century. Of the 18 UWM CAREER grant winners named in the last 15 years, all but one are still active faculty members.

Siemens earned his doctorate in astrophysics at Tufts University. Before joining the UWM Physics Department in 2006, he conducted postdoctoral research at the California Institute of Technology and UWM.

His interests are in gravitational wave astrophysics, astronomy, early universe cosmology and cosmic strings.