Submitted on February 25, 2009
Accepted on April 12, 2009
A Radio Pulsar/X-ray Binary Link
Anne M. Archibald 1*, Ingrid H. Stairs 2, Scott M. Ransom 3, Victoria M. Kaspi 1, Vladislav I. Kondratiev 4, Duncan R. Lorimer 5, Maura A. McLaughlin 6, Jason Boyles 5, Jason W. T. Hessels 7, Ryan Lynch 8, Joeri van Leeuwen 7, Mallory S. E. Roberts 9, Frederick Jenet 10, David J. Champion 11, Rachel Rosen 12, Brad N. Barlow 13, Bart H. Dunlap 13, Ronald A. Remillard 14
1 Department of Physics, McGill University, 3600 rue University, Montréal, QC, H3A 2T8 Canada.
2 Department of Physics and Astronomy, University of British Columbia,; Australia Telescope National Facility, Commonwealth Scientific and Industrial Research Organisation, P.O. Box 76, Epping NSW 1710, Australia.; Centre for Astrophysics & Supercomputing, Swinburne University of Technology
3 National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22901, USA.
4 Department of Physics, West Virginia University, 210 Hodges Hall, Morgantown, WV 26506, USA.; National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22901, USA.; Astro Space Center of the Lebedev Physical Institute, Profsoyuznaya str. 84/32, Moscow 117997, Russia.
5 Department of Physics, West Virginia University, 210 Hodges Hall, Morgantown, WV 26506, USA.; National Radio Astronomy Observatory, Green Bank, WV 24944, USA.
6 Department of Physics, West Virginia University, 210 Hodges Hall, Morgantown, WV 26506, USA.; National Radio Astronomy Observatory, Green Bank, WV 24944, USA.; Alfred P. Sloan Fellow.
7 Netherlands Institute for Radio Astronomy (ASTRON) Postbus 2, 7990 AA Dwingeloo, Netherlands.; Astronomical Institute "Anton Pannekoek," University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, Netherlands.
8 Department of Astronomy, University of Virginia, Charlottesville, VA 22904–4325, USA.
9 Eureka Scientific, 2452 Delmer St., Suite 100, Oakland, CA 94602-3017, USA.
10 Department of Physics and Astronomy, University of Texas at Brownsville, 80 Fort Brown, Brownsville, TX 78520, USA.
11 Australia Telescope National Facility, Commonwealth Scientific and Industrial Research Organisation, P.O. Box 76, Epping NSW 1710, Australia.
12 National Radio Astronomy Observatory, Green Bank, WV 24944, USA.
13 Department of Physics and Astronomy, University of North Carolina at Chapel Hill, CB 3255, Phillips Hall, Chapel Hill, NC 27599–3255, USA.
14 MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, 37-287, Cambridge, MA 02139, USA.
* To whom correspondence should be addressed.
Anne M. Archibald , E-mail: aarchiba{at}physics.mcgill.ca
Radio pulsars with millisecond spin periods are thought to have been spun up by transfer of matter and angular momentum from a low-mass companion star during an x-ray-emitting phase. The spin periods of the neutron stars in several such low-mass x-ray binary (LMXB) systems have been shown to be in the millisecond regime, but no radio pulsations have been detected. Here, we report on detection and follow-up observations of a nearby radio millisecond pulsar (MSP) in a circular binary orbit with an optically identified companion star. Optical observations indicate that an accretion disk was present in this system within the last decade. Our optical data show no evidence that one exists today, suggesting that the radio MSP has turned on after a recent LMXB phase.
