Multiwavelength Analysis of the Gamma-ray Binary LS I +61 303
Abstract
We present a multiwavelength analysis of the γ-ray binary system, LS I +61 303. LS I +61 303 is a high-mass X-ray binary (HMXB) that also emits strongly at γ-ray energies. We have analyzed five years worth of data from the Fermi Gamma-ray Observatory and find a clear periodicity of 26.7 days in the GeV flux, matching previous studies. The Fermi data also show evidence for long-term modulation matching the previously reported 1667 day (4.5 year) super-orbital period. We also compare the Fermi data to variations in Hα spectra taken at different super-orbital phases and look for correlations between the optical and γ-ray emission. LS I +61 303 has long been thought to consist of a classical Be star as the primary along with a compact secondary (neutron star or black hole); however, we present new optical spectroscopy that suggests the star is more evolved than previously thought. The results of this study bring the properties of the binary system into better focus so that we may begin to understand the true nature of this high-mass gamma-ray binary system.
- Publication:
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American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22315545A