Parkes observations for project P1211 semester 2024APRS_12

Traditional pulsar searching techniques are not sensitive enough to extreme pulsars such as millisecond pulsars (MSPs) in compact binaries (e.g., Pulsar-Blackhole binary systems), extremely fast spinning pulsars (e.g., sub-MSPs), and high dispersion measure (DM) pulsars. Such a situation is now changed thanks to the development of next generation radio telescope arrays such as Australian Square Kilometer Array Pathfinder (ASKAP). ASKAP is capable of conducting highly sensitive radio continuum surveys with wide sky coverage (e.g, Evolutionary Map of The Universe survey). One of the solutions is to find pulsar candidates in radio continuum surveys such as ASKAP surveys and then carry out targeted searches. This technique allows us to search over the wide bandwidth with full field of view while avoiding the need for expensive pixel-by-pixel high time resolution searches. In this proposal, we propose to observe 16 pulsar candidates identified in the Galactic plane using new ASKAP EMU images. We found 22 candidates by selecting sources with spectral index steeper than -2.0 and compactness less than 1.2. Among them 13 are known pulsars and a reasonable number of candidates to follow up (9 sources). In total, we have 16 candidates including seven sources from 2023APRS semester. Because of the dense ionised medium in the Galactic Plane, MSPs are likely to be missed by previous pulsar surveys carried out at 1.4 GHz. Here, we propose a targeted pulsar search with the Parkes UWL which allow us to search pulsation at higher frequencies and therefore avoid strong DM smearing and scattering effects.传统脉冲星搜寻技术对致密双星系统（如脉冲星-黑洞双星系统）中的毫秒脉冲星（millisecond pulsars, MSPs）、极高速旋转脉冲星（如亚毫秒脉冲星）以及高色散量（dispersion measure, DM）脉冲星这类极端脉冲星的灵敏度不足。随着澳大利亚平方千米阵列探路者（Australian Square Kilometer Array Pathfinder, ASKAP）等下一代射电望远镜阵列的发展，这一困境已得到改观。ASKAP具备开展高灵敏度大天区覆盖射电连续谱巡天的能力，例如宇宙演化图巡天（Evolutionary Map of The Universe survey）。一种可行的解决方案是在ASKAP巡天等射电连续谱巡天项目中识别脉冲星候选体，随后开展针对性搜寻。该技术可在全视场宽带宽范围内完成搜寻，同时无需开展成本高昂的逐像素高时间分辨率搜索工作。在本研究提案中，我们计划利用ASKAP获取的全新EMU图像，对银道面中已识别出的16个脉冲星候选体开展观测。我们通过筛选谱指数陡于-2.0且紧凑度小于1.2的源，共筛选出22个候选体，其中13个为已知脉冲星，剩余9个为值得开展后续研究的候选体。本次共计纳入16个候选体，其中7个来自2023年APRS学期项目。由于银道面内存在致密电离介质，过往在1.4 GHz频段开展的脉冲星巡天极有可能遗漏MSPs。为此，我们提出利用帕克斯UWL望远镜开展针对性脉冲星搜寻，该方案可在更高频段搜索脉冲信号，从而规避严重的DM展宽与散射效应。