The Einstein@Home search for new neutron stars

University Of Wisconsin-Milwaukee, Milwaukee WI

Investigators

Abstract

Einstein@Home is a volunteer distributed computing project. When otherwise idle, home computers download astronomical data from the Einstein@Home servers, search it for weak signals, and upload the results. The aim of Einstein@Home is to discover new neutron stars, using gravitational wave data from the advanced LIGO and Virgo observatories, gamma-ray data from the Fermi Satellite, and radio data from the Arecibo Observatory and other radio telescopes. Neutron stars, the targets of this search, are extreme objects formed in supernova explosions. Although they are only about ten miles in diameter, they are more massive than the Sun. So far, most neutron stars have been discovered via pulsations that occur when their beamed electromagnetic emission regularly sweeps past the earth. However, while it is believed that the Milky Way contains about a hundred million neutron stars, fewer than 3000 have been detected so far. Gravitational waves might well be the only way to unveil this invisible population of extreme objects. A project run by the University of Wisconsin at Milwaukee has three goals to use Einstein@Home to (1) Make the first direct detection of gravitational waves from spinning neutron stars, and thus to observe these stars via a completely different physical mechanism, which would carry important new information about their internal structure and composition. (2) Make use of new high-frequency radio data from the MeerKAT telescope array in South Africa to discover neutron stars near the Galactic center. These would give the community a way to study the supermassive black hole that resides there, as well as the dense and active region around it. (3) Use gamma-ray data to identify radio-quiet millisecond gamma-ray pulsars, providing new evidence about the evolution and emission of pulsars. Einstein@Home is an outstanding public outreach effort, allowing people world-wide to contribute directly to exciting and cutting-edge scientific research. Since it began, Einstein@Home volunteers have donated more than 3 billion CPU-core hours of computing time to the project. Using typical costing (cloud providers like Amazon, or super-computing centers) this represents more than 100 million dollars of computing time. This award also funds the continued operations and further development of Einstein@Home, including maintenance and administration of the central hardware and software infrastructure, the handling and post-processing of LIGO, Virgo, Fermi and radio data, and the design and implementation of improved search methods. The detection of continuous gravitational waves will provide glimpses into the invisible population of neutron stars that inhabits our Galaxy and shed light on their internal structure and evolutionary history. The discovery of new neutron stars in short period binaries and near the Galactic center will improve our understanding of stellar evolution and populations, help study the black hole at the Galactic center, and provide stringent tests of general relativity. Discovery of new millisecond radio pulsars will improve the ability of "pulsar timing arrays" to detect low-frequency gravitational waves. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.