The changing milliarcsecond radio morphology of the gamma-ray binary LS 5039

Abstract

Context. LS 5039 is one of the few TeV emitting X-ray binaries detected so far. The powering source of its multiwavelength emission can be accretion in a microquasar scenario or wind interaction in a young nonaccreting pulsar scenario. Aims. To present new high-resolution radio images and compare them with the expected behavior in the different scenarios. Methods. We analyze Very Long Baseline Array (VLBA) radio observations that provide morphological and astrometric information at milliarcsecond scales. Results. We detect a changing morphology between two images obtained five days apart. In both runs there is a core component with a constant flux density, and an elongated emission with a position angle (PA) that changes by 12+/-3 degrees between both runs. The source is nearly symmetric in the first run and asymmetric in the second one. The astrometric results are not conclusive. Conclusions. A simple and shockless microquasar scenario cannot easily explain the observed changes in morphology. An interpretation within the young nonaccreting pulsar scenario requires the inclination of the binary system to be very close to the upper limit imposed by the absence of X-ray eclipses.

To be published in A&A main journal. 5 pages, 1 figure. A reference has been corrected

References in corpus (3)

• Gamma-ray binaries: pulsars in disguise ?
• Orbital X-Ray Variability of the Microquasar LS 5039
• Confirmation of persistent radio jets in the microquasar LS 5039

Cited by in corpus (12)

• Understanding the Very High-Energy Emission from Microquasars
• Pulsar wind zone processes in LS 5039
• Discovery of slow X-ray pulsations in the high-mass X-ray binary 4U 2206+54
• INTEGRAL observation of hard X-ray variability of the TeV binary LS5039 / RX J1826.2-1450
• Estimating the contribution of Galactic sources to the diffuse neutrino flux
• Neutrino signal from gamma-ray loud binaries powered by high energy protons
• Radio absorption in high-mass gamma-ray binaries
• Low frequency radio spectrum and spectral turnover of LS 5039
• Studying the properties of the radio emitter in LS 5039
• Properties of a hypothetical cold pulsar wind in LS~5039
• Investigation of the broadband emission of the gamma-ray binary HESS J0632+057 using an intrabinary shock model
• Polarization study of gamma-ray binary