Discovery of a millisecond pulsar in the 5.4 day binary 3FGL J1417.5–4402: Observing the late phase of pulsar recycling
- Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)
- CSIRO Astronomy and Space Science, Australia Telescope National Facility, Epping, NSW 1710 (Australia)
- National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)
- Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States)
- Department of Astronomy and Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853 (United States)
- CSIRO Parkes Observatory, Parkes, NSW 2870 (Australia)
- Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122 (Australia)
- NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
In a search of the unidentified Fermi gamma-ray source 3FGL J1417.5–4402 with the Parkes radio telescope, we discovered PSR J1417–4402, a 2.66 ms pulsar having the same 5.4 day orbital period as the optical and X-ray binary identified by Strader et al. The existence of radio pulsations implies that the neutron star is currently not accreting. Substantial outflows from the companion render the radio pulsar undetectable for more than half of the orbit, and may contribute to the observed Hα emission. Our initial pulsar observations, together with the optically inferred orbit and inclination, imply a mass ratio of 0.171 ± 0.002, a companion mass of M{sub 2}=0.33±0.03 M{sub ☉}, and a neutron star mass in the range 1.77⩽M{sub 1}⩽2.13 M{sub ☉}. However, there remains a discrepancy between the distance of 4.4 kpc inferred from the optical properties of the companion and the smaller radio dispersion measure distance of 1.6 kpc. The smaller distance would reduce the inferred Roche-lobe filling factor, increase the inferred inclination angle, and decrease the masses. As a wide binary, PSR J1417–4402 differs from the radio-eclipsing black widow and redback pulsars being discovered in large numbers by Fermi. It is probably a system that began mass transfer onto the neutron star after the companion star left the main sequence. The companion should end its evolution as a He white dwarf in a 6–20 day orbit, i.e., as a typical binary millisecond pulsar companion.
- OSTI ID:
- 22890133
- Journal Information:
- Astrophysical Journal, Vol. 820, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
- Country of Publication:
- United Kingdom
- Language:
- English
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