Size of the Vela Pulsar's Emission Region at 18 cm Wavelength
C. R. Gwinn, M. D. Johnson, J. E. Reynolds, D. L. Jauncey, A. K. Tzioumis, H. Hirabayashi, H. Kobayashi, Y. Murata, P. G. Edwards, S. Dougherty, B. Carlson, D. … 展开作者
C. R. Gwinn, M. D. Johnson, J. E. Reynolds, D. L. Jauncey, A. K. Tzioumis, H. Hirabayashi, H. Kobayashi, Y. Murata, P. G. Edwards, S. Dougherty, B. Carlson, D. del Rizzo, J. F. H. Quick, C. S. Flanagan, P. M. McCulloch
We present measurements of the linear diameter of the emission region of the Vela pulsar at observing wavelength lambda=18 cm. We infer the diameter as a function of pulse phase from the distribution of visibility on the Mopra-Tidbinbilla baseline. As we demonstrate, in the presence of strong scintillation, finite size of the emission region produces a characteristic W-shaped signature in the projection of the visibility distribution onto the real axis. This modification involves heightened probability density near the mean amplitude, decreased probability to either side, and a return to the zero-size distribution beyond. We observe this signature with high statistical significance, as compared with the best-fitting zero-size model, in many regions of pulse phase. We find that the equivalent full width at half maximum of the pulsar's emission region decreases from more than 400 km early in the pulse to near zero at the peak of the pulse, and then increases again to approximately 800 km near the trailing edge. We discuss possible systematic effects, and compare our work with previous results.
PSR J1357-6429是一颗类似船帆座的射电脉冲星，最近被钱德拉和费米探测到，它像船帆座一样，为一个紧凑的X射线脉冲星风星云和X射线射电plerion提供动力，与一个扩展的TeV源有关。我们提出了我们的深光学观测与甚大望远镜寻找光学对应的脉冲星及其星云。我们在V、R和I波段探测到一个点状源，其位置与脉冲星的X射线位置一致，其颜色与普通恒星不同。该源的初步光度和效率与船帆座脉冲星相似，也支持了光学鉴别。然而，源光谱异常陡峭，光谱指数约为5，这不是典型的光学光谱。从PSR J1357-6429的射电位置的源偏移，与X射线位置的相应偏移一致，意味着脉冲星在2-2.5 kpc距离处的横向速度为1600-2000 km/s，使其成为已知移动最快的脉冲星。
