The Orbit and Companion of Probable gamma-ray Pulsar J2339-0533
Abstract
We have measured dramatic flux and spectral variations through the 0.193d orbit of the optical counterpart of the unidentified gamma-ray source 0FGL J2339.8-0530. This compact object companion is strongly heated, with Teff varying from ~6900K (superior conjunction) to <3000K at minimum. A combined fit to the light curve and radial velocity amplitudes implies M1 ~ 0.075Msun, M2 ~ 1.4 Msun and inclination i ~ 57deg. Thus this is a likely `black widow' system with Edot~1034-34.5 erg/s pulsar driving companion mass loss. This wind, also suggested by the X-ray light curve, may prevent radio pulse detection. Our measurements constrain the pulsar's reflex motion, increasing the possibility of a pulse detection in the gamma-ray signal.
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