Speaker
Description
LS 5039 is a High Mass X-ray Binary (HMXRB) comprising a compact object in an eccentric 3.9 day orbit around a massive O6.5V star. It is one of the most studied object in the field. A first HESS publication in 2004 established multi-TeV emission from the system (first ever TeV binary system). A second publication in 2006 , based on a deeper data set of ∼ 70h of observation, established the TeV orbital variability of the source. The period was measured to 3.9078 ± 0.0015 days, compatible with the ephemeris value of 3.90603 ± 0.00017 days, and spectral variability attributed to phase-dependent absorption by pair creation on the stellar photon field was reported.
Since 2006, a rather large amount of data was collected by H.E.S.S. with varying offset, in particular in the framework of the HESS Galactic Plane Survey, and for various neighboring sources. The available archival data set of ∼ 200 live hours and the improved analysis techniques developed since the early days of H.E.S.S. allows revisiting the source with unprecedented accuracy. With more than 5000 collected gamma-ray, detailed measurement of the spectral variability in bins of width of 0.1 in phase are now possible.
Detailed results on the orbital variability of LS 5039 and its interpretation will be presented at the conference.
| Collaboration(s) | H.E.S.S. |
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