LS 5039 / RX J1826.2-1450: A Young Pulsar?

摘要

Recent XMM-Newton and Chandra observations of the high mass X-ray binary LS 5039 / RX J1826.2-1450 caught the source in a faint X-ray state. In contrast with previous Rossi-XTE observations, we fail to detect any evidence of iron line emission. We also fail to detect X-ray pulsations. The X-ray spectrum can be well fitted by a simple powerlaw, slightly harder than in previous observations, and does not require the presence of any additional disk or blackbody component. XMM-Newton data imply a X-ray photoelectric absorption consistent with optical reddening (NH ~ 7 × 1021 cm–2), indicating that no strong local absorption occurs. Among the possible source emission mechanisms and hypotheses on the nature of the compact object, a young pulsar scenario may be the most appropriate.