标题： 射电明亮和射电安静的X射线双星：LSI+61o303 星系 显示英文标题

标题： Radio-loud and radio-quiet X-ray binaries: LSI+61o303 Galaxies

摘要： 这三个基本要素——一个旋转的致密天体、吸积盘和集束相对论喷流——使微类星体成为一种星系尺度上的缩小版射电活跃活动星系核（AGN）。 这解释了为什么这种新一类天体引起了极大的兴趣，迄今为止这类天体成员还不到20个。 微类星体属于更大的X射线双星系统类别，其中存在一个致密天体以及其发出X射线的吸积盘，但缺少相对论喷流。 何时一个X射线双星系统会演化为微类星体？ 研究这种转变的理想对象是周期性微类星体LSI+61°303，它由从Be星赤道风中吸积物质的致密天体组成，并且在其偏心轨道上有多次超临界吸积和喷发事件。 对于近日点经过时的喷发，高能逆康普顿散射会使Be星的紫外光子损失严重：在近日点经过时观测到伽马射线发射，而在20年的射电通量监测中从未观测到射电爆发。 对于偏离近日点经过的喷发，损失较小，可以观测到射电爆发。 在几AU到数百AU尺度上绘制的射电发射显示了一个双侧相对论性（β=0.6c）S形喷流，类似于著名的SS433进动喷流。 显示英文摘要

摘要： The three basic ingredients - a spinning compact object, an accretion disc and a collimated relativistic jet - make microquasars a galactic scaled-down version of the radio-loud AGN. That explains the large interest attributed to this new class of objects, which up to now consists of less than 20 members. Microquasars belong to the much larger class of X-ray binary systems, where there exits a compact object together with its X-ray emitting accretion disc, but the relativistic jet is missing. When does an X-ray binary system evolve into a microquasar? Ideal for studying such kind of a transition is the periodic microquasar LSI+61deg303 formed by a compact object accreting from the equatorial wind of a Be star and with more than one event of super-critical accretion and ejection along the eccentric orbit. For ejections at periastron passage the relativistic electrons suffer severe inverse Compton losses by upscattering the UV photons of the Be star at high energy : At periastron passage Gamma-ray emission has been observed, whereas radio outbursts have never been observed in 20 years of radio flux monitoring. For ejections displaced from periastron passage the losses are less severe and radio outbursts are observed. The radio emission mapped on scales from a few AU to hundreds of AU shows a double-sided relativistic (beta=0.6c) S-shaped jet, similar to the well-known precessing jet of SS433.