Parkes observations for project P1211 semester 2024APRS_19

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极端脉冲星的探测灵敏度不足，这类极端脉冲星包括密近双星系统中的毫秒脉冲星（millisecond pulsars, MSPs，例如脉冲星-黑洞双星系统）、极快自转脉冲星（如亚毫秒脉冲星，sub-MSPs）以及高色散量（dispersion measure, DM）脉冲星。如今，随着澳大利亚平方千米阵探路者（Australian Square Kilometer Array Pathfinder, ASKAP）这类新一代射电望远镜阵列的发展，这一局面得到了有效改观。ASKAP具备开展高灵敏度、大天区覆盖射电连续谱巡天的能力，例如宇宙演化地图巡天（Evolutionary Map of The Universe, EMU）。其中一种可行解决方案是，在ASKAP巡天等射电连续谱巡天中筛选脉冲星候选体，随后开展针对性搜寻。该技术可在全视场范围内对宽频带进行搜寻，同时无需开展成本高昂的逐像素高时间分辨率搜寻工作。在本研究提案中，我们计划利用最新的ASKAP EMU图像，对银道面中识别出的16颗脉冲星候选体开展观测。我们通过筛选谱指数陡于-2.0、紧凑度小于1.2的源，共得到22颗候选体，其中13颗为已知脉冲星，剩余9颗源具备开展后续研究的合理价值。本次共纳入16颗候选体，其中7颗来自2023APRS学期观测计划。由于银道面存在稠密的电离介质，此前在1.4 GHz频段开展的脉冲星巡天很可能遗漏了毫秒脉冲星（MSPs）。为此，我们计划使用帕克斯UWL望远镜开展针对性脉冲星搜寻，该设备可在更高频段搜寻脉冲信号，从而规避强烈的DM弥散与散射效应。