Race to Detect Gravitational Waves Advances with New NSF-funded NANOGrav Physics Frontiers Center
The National Science Foundation (NSF) has awarded the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) $14.5 million over 5 years to create and operate a Physics Frontiers Center (PFC).
The NANOGrav PFC will address a transformational challenge in astrophysics: the detection of low-frequency gravitational waves. Gravitational waves are elusive ripples in the fabric of space-time, which theories predict should arise from extremely energetic and large-scale cosmic events, such as orbiting pairs of massive black holes found at the centers of merging galaxies, phase transitions in the very early Universe, or as relics from cosmic inflation, the period just after the Big Bang when all of the Universe that we can see expanded rapidly from a minuscule volume in a tiny fraction of a second.
In Einstein's theory of gravity, these events produce waves that distort, or ripple, the actual fabric of the cosmos as they emanate throughout space. The waves have such a long wavelength—significantly larger than our Solar System—that we cannot build a detector large enough to observe them. Fortunately, the Universe itself has created its own detection tool, millisecond pulsars—the rapidly spinning, superdense remains of massive stars that have exploded as supernovas. These ultra-stable stars are nature's most precise celestial clocks, appearing to "tick" every time their beamed emissions sweep past the Earth like a lighthouse beacon. Gravitational waves may be detected in the small but perceptible fluctuations—a few tens of nanoseconds over five or more years—they cause in the measured arrival times at Earth of radio pulses from these millisecond pulsars.
NANOGrav was founded in 2007 and at the time consisted of 17 members in the United States and Canada. It has since grown to 55 scientists and students at 15 institutions. The NANOGrav PFC will provide funding for 23 senior personnel, 6 postdoctoral researchers, 10 graduate students, and 25 undergraduate students distributed across 11 institutions.
Xavier Siemens, a physicist at the University of Wisconsin-Milwaukee, is the Principal Investigator (PI) for the project and will serve as Director of the Center. Maura McLaughlin, an astronomer at West Virginia University, will serve as Co-Director.
NSF currently supports nine other PFCs, which range in research areas from theoretical biological physics and the physics of living cells to quantum information and nuclear astrophysics. By bringing together astronomers and physicists from across the United States and Canada to search for the telltale signature of gravitational waves buried in the incredibly steady ticking of distant pulsars, NANOGrav is advancing the PFC mission to "foster research at the intellectual frontiers of physics" and to "enable transformational advances in the most promising research areas."
"NANOGrav is now poised to detect low-frequency gravitational waves," said Siemens. "This Center will ensure that researchers have the resources necessary to explore one of the most exciting frontiers in all of physics and astronomy."
This research makes use of the unique capabilities and sensitivity of the Arecibo Observatory in Puerto Rico and the National Radio Astronomy Observatory's Green Bank Telescope (GBT). The GBT is located in the National Radio Quiet Zone, which protects the incredibly sensitive telescope from unwanted radio interference, enabling it to study pulsars and other astronomical objects. Arecibo is the largest single dish radio telescope in the world today.
"NANOGrav is fortunate to have access to the two most sensitive telescopes in the world for this groundbreaking research", McLaughlin stated. "Furthermore, as many of our observations are performed by students, the telescopes are serving a vital role in creating a pipeline for science and technology fields."
USRA participates in the NANOGrav PFC through the work of Zaven Arzoumanian, Senior Scientist with the Center for Research and Exploration in Space Science & Technology (CRESST) at NASA's Goddard Space Flight Center. Dr. Arzoumanian was a founding member of the NANOGrav collaboration and brings over 25 years of experience in pulsar research to the effort.
"The new NSF Physics Frontiers Center enables NANOGrav to develop the 'critical mass' of technical and human resources needed to finally detect low-frequency gravitational waves, if they exist at predicted levels, and to understand the powerful processes that generate them," said Arzoumanian.
USRA also manages the radio and planetary astronomy programs at Arecibo Observatory as a member of a team of institutions led by SRI International and including the Universidad Metropolitana (UMET) responsible for the Observatory's operations through a separate agreement with the NSF. "The PFC demonstrates the importance of Arecibo as a forefront facility for answering some of the most exciting questions in astronomy and physics," said Arzoumanian, a former Director of Astronomy at Arecibo and now Science Lead for an upcoming NASA mission to study pulsars, the Neutron Star Interior Composition Explorer (NICER), scheduled to launch in 2016.
Universities Space Research Association is an independent, nonprofit research corporation where the combined efforts of in-house talent and university-based expertise merge to advance space science and technology. USRA works across disciplines including biomedicine, planetary science, astrophysics, and engineering and integrates those competencies into applications ranging from fundamental research to facility management and operations. USRA engages the creativity and authoritative expertise of the research community to develop and deliver sophisticated, forward-looking solutions to Federal agencies and other government sponsors.
The research performed by the PFC is distributed among the participating institutions and members of NANOGrav. The personnel funded by the NANOGrav PFC include:
California Institute of Technology
Franklin and Marshall College
Montana State University
Universities Space Research Association and NASA's Goddard Space Flight Center
National Radio Astronomy Observatory
University of Texas at Brownsville
University of Wisconsin-Milwaukee
West Virginia University
They collaborate closely with Ingrid Stairs at the University of British Columbia in Vancouver, Canada, and Victoria Kaspi at McGill University in Montreal, Canada.