Gamma-ray binaries are a small subclass of the high mass X-ray binary population which exhibit emission across the whole electromagnetic spectrum. We present radial velocities of 1FGL J1018.6−5856 based on observations obtained with the Southern African Large Telescope (SALT). We combine our measurements with those published in the literature to get a broad phase coverage. The mass function obtained supports a neutron star compact object, although a black hole mass is possible for very low inclination angles. The improved phase coverage allows constraints to be placed on the orbital eccentricity (e = 0.31 ± 0.16), which agrees with estimates from high-energy data.
@article{arxiv.1708.07886,
title = {The orbit of the gamma-ray binary 1FGL J1018.6-5856},
author = {Itumeleng Monageng and Vanessa McBride and Lee Townsend and Alexei Kniazev and Shazrene Mohamed and Markus Böttcher},
journal= {arXiv preprint arXiv:1708.07886},
year = {2017}
}
Comments
6 pages, 5 figures, accepted for publication in ApJ