Parkes observations for project P976 semester 2018APRS_11

Spider pulsars - black widows (BW) and redbacks (RB) - reside in incredibly tight orbits with low-mass stellar companions. The close proximity of the two orbiting bodies leads to heavy irradiation of the companion by the pulsar wind, causing material to be driven from its surface. This excess material is not gravitationally bound to the star, and the extent to which it reaches can only be constrained by observing the duration of eclipses of the radio pulsar emission that it causes. Little information about these systems is set in stone: the physical processes behind the eclipses, the dimensions, densities and magnetic properties of the eclipse medium, mass loss rates and subsequent evolution of the companions, are all unknown. Previous radio studies of a handful of spider systems have highlighted the importance of high-time resolution and large frequency coverage in constraining their properties. Measurement of the flux density, dispersion measure, rotation measure and depolarisation of the pulsars, as a function of the orbits, directly probes the eclipse process and properties of the medium causing it. All of these measurables are frequency dependent, thus with ultra-wideband observations we will have access to an unparalleled insight into spider pulsar systems. We plan to observe three eclipses for each of three BWs and two RBs in order to constrain variability between the two classes, multiple systems within each class, and the eclipses in an individual system. In addition, such observations will demonstrate and help to optimise the capabilities of the new UWL receiver.

蜘蛛脉冲星——包括黑寡妇（BW）与红背（RB）两类——均处于与低质量伴星紧密至极的轨道中。轨道两天体的极近距离会导致脉冲星风对伴星产生强烈辐射，进而将伴星表面物质剥离。这些过剩物质无法被恒星的引力束缚，其扩散范围仅能通过观测其引发的射电脉冲星辐射掩食的持续时长来约束。目前对这类天体系统的认知仍有诸多未知：掩食背后的物理机制、掩食介质的尺度、密度与磁特性、物质抛射率以及伴星的后续演化等问题均未明晰。此前针对少量蜘蛛脉冲星系统的射电研究已凸显出高时间分辨率与宽频率覆盖范围对约束该类天体特性的重要性。通过测量脉冲星的流量密度、色散量（dispersion measure）、旋转量（rotation measure）以及去极化程度随轨道相位的变化，可直接探究掩食过程及引发掩食的介质特性。上述所有可测量参数均与频率相关，因此借助超宽带观测，我们将能前所未有地深入解析蜘蛛脉冲星系统。我们计划对3颗黑寡妇脉冲星与2颗红背脉冲星各自开展3次掩食观测，以此约束两类天体间的特性差异、每一类内多系统间的差异，以及单系统内的掩食变化特性。此外，此类观测还将验证并助力优化新型UWL接收机的性能。