Volume 481, Number 1, April I 2008Science with Hinode
|Page(s)||17 - 20|
|Published online||25 January 2008|
The changing milliarcsecond radio morphology of the gamma-ray binary LS 5039
Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain e-mail: [mribo;jmoldon]@am.ub.es; email@example.com
2 Departamento de Física (EPS), Universidad de Jaén, Campus Las Lagunillas s/n, 23071 Jaén, Spain
3 Max Planck Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
Accepted: 21 December 2007
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 ± 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.
Key words: stars: individual: LS 5039 / X-rays: binaries / radio continuum: stars / radiation mechanism: non-thermal
© ESO, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.