Parkes observations for project P976 semester 2018APRS_09

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——黑寡妇（Black Widows, BW）与红背（Redbacks, RB）两类——均与低质量伴星处于极紧凑的轨道系统中。两个天体的极近间距使得脉冲星风对伴星产生强烈辐照，进而驱使伴星表面物质向外抛射。这类过剩物质不受恒星引力束缚，其所能抵达的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加以约束。目前关于这类系统的信息大多尚未确定：掩食背后的物理过程、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，均未明确。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在约束其特性方面的重要性。对脉冲星的流量密度、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进行测量，可直接揭示掩食过程及其引发介质的特性。上述所有可测量参数均与频率相关，因此通过超宽带（Ultra-Wideband, UWL）观测，我们将能够前所未有地深入了解蜘蛛脉冲星系统。本研究计划对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，以期约束两类脉冲星之间的特性差异、每一类内多个系统间的差异，以及单个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。