出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：LS 5039 is one of the four TeV emitting X-ray binaries detected up to now. The powering source
of its multi-wavelength emission can be accretion in a microquasar scenario or wind interaction
in a young non-accreting pulsar scenario. These two scenarios predict different morphologic and
peak position changes along the orbital cycle of 3.9 days, which can be tested at milliarcsecond
scales using VLBI techniques. Here we present a campaign of 5 GHz VLBA observations conducted
in June 2000 (2 runs ve days apart). The results show a core component with a constant
ux density, and a fast change in the morphology and the position angle of the elongated extended
emission, but maintaining a stable ux density. These results are difcult to t comfortably within
a microquasar scenario, whereas they appear to be compatible with the predicted behavior for a
non-accreting pulsar.
