Parkes observations for project P897 semester 2017APRS

Modulation of pulse times of arrival (TOAs) from pulsars often heralds excitement: planetary companions, neutron star free precession, and the poorly understood but crucially important process of magnetospheric state switching can all produce quasi-periodic TOA modulation. In a sample of 150 young pulsars, we have detected periodic modulation in six pulsars. We propose to obtain multi-epoch, deep, well-calibrated 10 cm pulse profiles to search for profile variability, particularly variability correlated with TOA modulation. The absence of such variation may lend credence to a planet interpretation, while detection will help characterize the magnetospheric states and determine if free precession plays a role. Because the pulsars are largely southern sky objects, and because the 10cm band is largely free from RFI and scattering, Parkes is uniquely capable to deliver this science.

脉冲星的脉冲到达时间（TOAs）调制现象往往预示着重大科学发现：行星伴星、中子星自由进动，以及这一尚不明晰却至关重要的磁层状态转换过程，均可产生准周期的脉冲到达时间调制。在150颗年轻脉冲星的样本中，我们已在其中6颗脉冲星中探测到周期性调制现象。我们拟开展多历元、深曝光且校准精良的10厘米波段脉冲轮廓观测，以搜寻脉冲轮廓的变化性，尤其是与脉冲到达时间调制相关的变化性。若未观测到此类变化，则可增强行星伴星假说的可信度；而若探测到变化，则将有助于表征磁层状态，并厘清自由进动是否发挥作用。由于本次研究涉及的脉冲星大多位于南天天区，且10厘米波段受射频干扰（Radio Frequency Interference, RFI）与星际散射的影响极小，因此帕克斯（Parkes）望远镜是开展此项科研工作的唯一理想平台。