LOFAR Discovery of the Fastest-spinning Millisecond Pulsar in the Galactic Field
- ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, NL-7990 AA Dwingeloo (Netherlands)
- Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada)
- Center for Research and Exploration in Space Science, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
- Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom)
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands)
- Albert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik, D-30167 Hannover (Germany)
- Key Laboratory of Optical Astronomy, National Astronomical Observatories Chinese Academy of Sciences, Beijing 100012 (China)
- Department of Physics, University of Washington, Seattle, WA 98195-1560 (United States)
- Square Kilometre Array South Africa, 7405 Pinelands (South Africa)
- W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
- National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM 87801 (United States)
- Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States)
We report the discovery of PSR J0952−0607, a 707 Hz binary millisecond pulsar that is now the fastest-spinning neutron star known in the Galactic field (i.e., outside of a globular cluster). PSR J0952−0607 was found using LOFAR at a central observing frequency of 135 MHz, well below the 300 MHz to 3 GHz frequencies typically used in pulsar searches. The discovery is part of an ongoing LOFAR survey targeting unassociated Fermi-Large Area Telescope γ-ray sources. PSR J0952−0607 is in a 6.42 hr orbit around a very low-mass companion (M{sub c}≳0.02 M{sub ⊙}), and we identify a strongly variable optical source, modulated at the orbital period of the pulsar, as the binary companion. The light curve of the companion varies by 1.6 mag from r{sup ′}=22.2 at maximum to r{sup ′}>23.8, indicating that it is irradiated by the pulsar wind. Swift observations place a 3σ upper limit on the 0.3−10 keV X-ray luminosity of L{sub X}<1.1×10{sup 31} erg s{sup −1} (using the 0.97 kpc distance inferred from the dispersion measure). Though no eclipses of the radio pulsar are observed, the properties of the system classify it as a black widow binary. The radio pulsed spectrum of PSR J0952−0607, as determined through flux density measurements at 150 and 350 MHz, is extremely steep with α∼−3 (where S∝ν{sup α}). We discuss the growing evidence that the fastest-spinning radio pulsars have exceptionally steep radio spectra, as well as the prospects for finding more sources like PSR J0952−0607.
- OSTI ID:
- 22872552
- Journal Information:
- Astrophysical Journal Letters, Vol. 846, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United Kingdom
- Language:
- English
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