标题： 重访维拉脉冲星的光学偏振 显示英文标题

标题： The Optical Polarisation of the Vela Pulsar revisited

摘要： 在这项工作中，我们给出了对 Vela 脉冲星（PSR B0833-45）相位平均光学偏振的修订测量值，迄今为止，只有 Wagner & Seifert (2000) 发表过一个数值。 我们的测量是通过对存档的使用 VLT 的 FORS 仪器获得的偏振观测数据的准确重新分析得到的。 我们测量到的相位平均线性偏振度为 P = 9.4% ± 4%，位置角为 146° ± 11°，与钱德拉探测到的 X 射线弧和喷流对称轴以及脉冲星自行非常接近。 我们将测得的相位平均光学偏振与不同脉冲星磁层模型的预期进行了比较。 我们发现所有模型一致地预测了比观测值大的相位平均线性偏振值。 这可能是由于现有模型忽略了各种去极化效应的贡献所导致的局限性。 有趣的是，对于外间隙模型，我们发现假设光学辐射为同步辐射时，观测到的偏振位置角也暗示了脉冲星自转轴与 X 射线弧和喷流对称轴之间的对齐关系。 显示英文摘要

摘要： In this work we present a revised measurement of the phase-averaged optical polarisation of the Vela pulsar (PSR B0833-45), for which only one value has been published so far (Wagner & Seifert 2000). Our measurement has been obtained through an accurate reanalysis of archival polarisation observations obtained with the FORS instrument at the VLT. We have measured a phase-averaged linear polarisation degree P=9.4% +/- 4% and a position angle 146 +/- 11 deg, very close to the ones of the axis of symmetry of the X-ray arcs and jets detected by Chandra and of the pulsar proper motion.We have compared the measured phase-averaged optical polarisation with the expectations of different pulsars' magnetosphere models. We have found that all models consistently predict too large values of the phase-averaged linear polarization with respect to the observed one. This is probably a consequence of present models' limitations which neglect the contributions of various depolarisation effects. Interestingly, for the outer gap model we have found that, assuming synchrotron radiation for the optical emission, the observed polarisation position angle also implies an alignment between the pulsar rotational axis and the axis of symmetry of the X-ray arcs and jets.