1FGL J1417.7-4407: A likely gamma-ray bright binary with a massive neutron star and a giant secondary

Jay Strader, Laura Chomiuk, C. C. Cheung, David J. Sand, Davide Donato, Robin H.D. Corbet, Dana Koeppe, Philip G. Edwards, Jamie Stevens, Leonid Petrov, Ricardo Salinas, Mark Peacock, Thomas Finzell, Daniel E. Reichart, Joshua B. Haislip

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


We present multiwavelength observations of the persistent Fermi-Large Area Telescope unidentified γ-ray source 1FGL J1417.7-4407, showing it is likely to be associated with a newly discovered X-ray binary containing a massive neutron star (nearly ) and a giant secondary with a 5.4 day period. SOAR optical spectroscopy at a range of orbital phases reveals variable double-peaked Hα emission, consistent with the presence of an accretion disk. The lack of radio emission and evidence for a disk suggests the γ-ray emission is unlikely to originate in a pulsar magnetosphere, but could instead be associated with a pulsar wind, relativistic jet, or could be due to synchrotron self-Compton at the disk-magnetosphere boundary. Assuming a wind or jet, the high ratio of γ-ray to X-ray luminosity (∼20) suggests efficient production of γ-rays, perhaps due to the giant companion. The system appears to be a low-mass X-ray binary that has not yet completed the pulsar recycling process. This system is a good candidate to monitor for a future transition between accretion-powered and rotational-powered states, but in the context of a giant secondary.

Original languageEnglish (US)
Article numberL12
JournalAstrophysical Journal Letters
Issue number1
StatePublished - May 1 2015
Externally publishedYes


  • Binaries: spectroscopic
  • Gamma rays: general
  • Pulsars: general
  • X-rays: binaries
  • X-rays: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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