The discovery of 17 new millisecond pulsars was announced today (Jan. 5) at the American Astronomical Society meeting by a team of researchers including Maura McLaughlin, assistant professor of physics at West Virginia University.
The pulsars, discovered in radio searches of unidentified gamma-ray sources found with the Large Area Telescope onboard NASA’s Fermi Gamma-ray Space Telescope satellite, represent a substantial increase in the number of known millisecond pulsars in the disk of the galaxy. They promise a bounty of science yields ranging from the potential direct detection of gravitational waves to gamma-ray emission mechanisms, stellar evolution and millisecond pulsar formation.
The discoveries are the result of a powerful synergy between gamma-ray and radio observations made possible by the Large Area Telescope’s unprecedented ability to pinpoint gamma-ray sources.
McLaughlin and colleagues including WVU student Priyadarshini Bangale, Mallory Roberts with Eureka Scientific; Jason Hessels with ASTRON: Netherlands Institute for Radio Astronomy; Scott Ransom with the National Radio Astronomy Observatory in Charlottesville, Va.; Paul Ray with the U.S. Naval Research Laboratory in Washington, D.C.; Fernando Camilo with Columbia University; and Matthew Kerr with the University of Washington discovered five of the 17 sources with the Green Bank Telescope in Green Bank, W.Va.
The Large Area Telescope, the primary instrument on NASA’s Fermi Gamma-ray Space Telescope satellite, has been surveying the gamma-ray sky since its science mission began on Aug. 4, 2008.
Scientists on the Large Area Telescope team have been working to identify sources of gamma rays and produce a complete catalog from the first year of observations, consisting of over 1,000 sources. A number of these sources were suspected of being unknown pulsars up to now because they were not coincident with known classes of gamma ray-emitting sources and their spectral and variability characteristics were similar to known gamma-ray pulsars.
“We picked 50 sources that had gamma-ray properties similar to those of radio pulsars and observed those sources with the Green Bank Telescope. We are less than half-way through our search and have already found five new millisecond pulsars,” McLaughlin said. “It typically takes a year of blind searching to find this many.”
Millisecond pulsars are nature’s most precise clocks, with long-term stability that rivals man-made atomic clocks. Since the first millisecond pulsar was discovered 28 years ago, countless hours have been spent surveying the sky with radio telescopes and crunching the data with supercomputers, resulting in the discovery of about 60 millisecond pulsars in the galactic disk and more than 100 in globular clusters.
By using the Large Area Telescope sources as a finding chart and a modest investment in radio telescope time, astronomers have been able to increase the number of known millisecond pulsars in the disk of the galaxy by almost 30 percent.
Among the five new sources, there are two so-called “black widow” pulsars where the powerful wind from the pulsar is blowing away the companion and may eventually destroy it completely, leaving an isolated millisecond pulsar behind. These discoveries double the number of such systems known in the galactic disk and will be crucial for helping understand the evolution of millisecond pulsar systems.
These millisecond pulsars will also be important for efforts to detect the signatures of gravitational waves, a prediction of Albert Einstein’s theory of general relativity. By timing a network of high-precision millisecond pulsars, correlated changes in arrival times due to a background of gravitational waves could be detected. The most likely source that will be detected is a background due to black hole binaries. These new millisecond pulsars will provide a dramatic increase in sensitivity to these currently invisible sources.
NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the U.S.
For images and animations related to this release, please visit
http://www.nasa.gov/fermi .
For more information contact McLaughlin at maura.mclaughlin@mail.wvu.edu .
-WVU-
01/05/10
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