We present new optical spectroscopy of the gamma-ray binary LS 5039. Our data show evidence for sub-orbital modulation in the radial velocities with amplitude ~7 km/s and period ~Porb/4. This short-term oscillation is stable over at least 7 years and it is likely triggered by non-radial oscillations of the O6.5V optical star. We also present the results of a spectroscopic campaign on MWC 148, the optical counterpart of the new gamma-ray binary candidate HESS J0632+067. Long-term variations in the Halpha and Hbeta emission line parameters are clearly detected which, if modulated with the binary orbit, would imply a period >200 days.
@article{arxiv.1012.4351,
title = {New Optical Results on gamma-ray Binaries},
author = {J. Casares and J. M. Corral-Santana and A. Herrero and J. C. Morales and T. Muñoz-Darias and I. Negueruela and J. M. Paredes and I. Ribas and M. Ribó and D. Steeghs and L. van Spaandonk and F. Vilardell},
journal= {arXiv preprint arXiv:1012.4351},
year = {2015}
}
Comments
4 pages, 2 figures, to be published in the proceedings of the 1st Sant Cugat Forum on Astrophysics, "ICREA Workshop on the high-energy emission from pulsars and their systems", held in April, 2010