%0 Journal Article
%T 1FGL J0523.5-2529: A New Probable Gamma-ray Pulsar Binary
%A Jay Strader
%A Laura Chomiuk
%A Eda Sonbas
%A Kirill Sokolovsky
%A David J. Sand
%A Alexander S. Moskvitin
%A C. C. Cheung
%J Physics
%D 2014
%I arXiv
%R 10.1088/2041-8205/788/2/L27
%X We report optical photometric and SOAR spectroscopic observations of an X-ray source found within the localization error of the Fermi-LAT unidentified gamma-ray source J0523.5-2529. The optical data show periodic flux modulation and radial velocity variations indicative of a binary with a 16.5-hr period. The data suggest a massive non-degenerate secondary (~> 0.8 M_sun), and we argue the source is likely a pulsar binary. The radial velocities have good phase coverage and show evidence for a measurable eccentricity (e=0.04). There is no clear sign of irradiation of the secondary in either photometry or spectroscopy. The spatial location out of the Galactic plane and gamma-ray luminosity of the source are more consistent with classification as a recycled millisecond pulsar than as a young pulsar. Future radio timing observations can confirm the identity of the primary and further characterize this interesting system.
%U http://arxiv.org/abs/1405.5533v2