The Orbit and Companion of Probable gamma-ray Pulsar J2339-0533

TL;DR

This study characterizes the orbital and spectral properties of a probable gamma-ray pulsar system, revealing a black widow configuration with implications for pulsar detection and understanding of pulsar wind interactions.

Contribution

It provides the first detailed measurements of flux, spectral variations, and system parameters for the gamma-ray source 0FGL J2339.8-0530, suggesting a black widow pulsar system.

Findings

The companion's temperature varies from ~6900K to <3000K over the orbit.

The system likely contains a pulsar with a mass around 1.4 solar masses.

The system's geometry and wind may hinder radio pulse detection.

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 T_eff varying from ~6900K (superior conjunction) to <3000K at minimum. A combined fit to the light curve and radial velocity amplitudes implies M_1 ~ 0.075M_sun, M_2 ~ 1.4 M_sun and inclination i ~ 57deg. Thus this is a likely `black widow' system with Edot~10^{34-34.5} 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.