This PIRE award will establish an international team for the detection and study of low frequency gravitational waves (GWs) using timing observations of millisecond pulsars (MSPs). GWs are ripples in the fabric of spacetime that emanate from massive objects in accelerated motion. MSPs are rapidly rotating highly magnetic neutron stars that emit pulses of radio waves - similar to flashes of light from a lighthouse - and GWs perturb the travel of these pulses from a pulsar to the Earth. Together with their international collaborators, U.S. researchers and students will use radio telescopes to observe signals from dozens of pulsars over several years. This will enable the PIRE team to directly test for the existence of GWs and, after detection, measure their sky distribution, polarization, and spectrum and identify and characterize their astrophysical sources. GWs are a key prediction of Einstein's theory of general relativity - the most complete description of gravity and spacetime - but until now only indirect evidence has pointed to their existence. Direct detection of GWs is one of the most transformational prospects of astrophysics, with the potential to revolutionize our knowledge of the universe by enabling studies of black holes within massive galaxies and the spacetime dynamics of early stages of the universe.
Both international collaboration and coordinated use of worldwide resources are critical for detecting low frequency gravitational waves. Detection sensitivity increases the longer the pulsars are monitored, so observations over many years are required. Pairs of MSPs must be observed from far distant points on earth to maximize sensitivity, thus requiring observing sites in both hemispheres. Additionally, long, frequent observations across many radio observing frequencies are required for high precision and must be done for as many MSPs as possible. All of these factors combine to place a substantial demand on the world's radio telescope time. This PIRE project will catalyze the International Pulsar Timing Array (IPTA) partnership between the North American NanoHertz Observatory for Gravitational waves (NANOGrav) and Australian, European, and Indian scientists and will focus a coordinated effort with dedicated research power on GW detection. By combining data taken at the world's best facilities, with the highest-precision detection techniques, with experts from around the world, the PIRE team expects to detect GWs within the 5-10 years.
This international project will contribute to a more diverse, globally-engaged, U.S. science and engineering workforce. It will train the first generation of astronomers able to directly observe and study GWs and will prepare U.S. junior participants to be the future leaders of this new field. They will gain the vital technical skills needed for pulsar timing and will also explore the impacts of such measurements on the fundamentals of astrophysics. The project will support postdoctoral researchers and graduate and undergraduate students at nine U.S. institutions, yearly international science meetings, student workshops, and research and observing trips. As students and researchers make observations at the telescope facilities, they will help to build an international mentoring network amongst different educational levels, institutions, and countries. The project will also exploit the fact that the world's best radio telescopes allow remote observing and control of the telescope, thus providing a way to involve more undergraduate and high school students in the project.
The project will strengthen the capacity of the U.S. institutions to internationalize their research, scientific networks, and curricula. This PIRE effort will broaden the virtual international reach of U.S. institutions as their faculty and students use cyberinfrastructure to access and analyze data from around the world, operate telescopes remotely, share experiences via social networking tools, and host international tutorials and web-based seminars. The U.S. institutions are members of the NANOGrav consortium that pools North American resources and this project will further solidify their U.S. and international linkages. Finally, once established, a consortium-wide Memorandum of Understanding (MOU) for the planned research/study abroad programs will continue to provide valuable opportunities for current and future generations of students at these institutions.
U.S. institutions include: Cornell University (NY), University of Texas at Brownsville, Franklin and Marshall College (PA), West Virginia University, Bryn Mawr College (PA), University of Vermont, National Radio Astronomy Observatory (NRAO) (VA), University of Wisconsin at Milwaukee, Oberlin College (OH), Universities Space Research Association & NASA Goddard Space Flight Center (MD), National Astronomy and Ionosphere Center (PR), and the Naval Research Laboratory (D.C.).
Foreign institutions include: Swinburne University (Australia), L'Observatoire de Paris at Nançay/Nançay Observatory (France), Max Planck Institute for Radio Astronomy (MPIfR) at the University of Bonn (Germany), National Center for Radio Astrophysics (NCRA) (India), Netherlands Institute for Radio Astronomy (ASTRON), Australia Telescope National Facility (ATNF), McGill University (Canada), Leiden University (The Netherlands), University of Manchester (UK), Osservatorio Astronomico di Cagliari (Italy), and University of British Columbia (Canada).
This PIRE project was cofunded by NSF's Office of International Science and Engineering and the Division of Astronomical Sciences.
