Optical polarimetric observations of the microquasar LS 5039

Abstract

We present the first optical polarimetric observations of the runaway microquasar LS 5039. Our results reveal the presence of a large amount (~5%) of polarized emission towards this binary system. By combining polarimetric and spectroscopic observations of some stars in the field together with available statistical information on the galactic interstellar polarization of the region, we have estimated and subtracted the contribution of the interstellar polarization in this direction. As a result, we obtain an intrinsic polarization of ~3% for the object, much higher than what would be expected from jet emission in the optical domain. We suggest that the polarized light originates by electron Thomson scattering in the stellar envelope of the companion star. This allows us to constrain the size of the region where the polarized emission originates, as well as estimating the scattering electronic density and the wind velocity at such distance.

arXiv comment5 pages, 2 figures, accepted for publication in A&A

References in corpus (7)

• Discovery of a High-Energy Gamma-Ray-Emitting Persistent Microquasar
• Statistical Properties of Galactic Starlight Polarization
• LS 5039: a runaway microquasar ejected from the galactic plane
• The N Enrichment and Supernova Ejection of the Runaway Microquasar LS 5039
• Confirmation of persistent radio jets in the microquasar LS 5039
• Long-term X-ray variability of the microquasar system LS 5039/RX J1826.2-1450
• Wind Accretion and Binary Evolution of the Microquasar LS 5039

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• First multicolour polarimetry of TeV gamma-ray binary HESS J0632+057 close to periastron passage