Parkes observations for project P1320 semester 2024APRS_07

Young pulsars are critical for probing the early stages of neutron stars, offering insights into their initial spin periods, velocities, and luminosities. If they is present in supernova remnants (SNRs) then they also illuminate the broader phenomena of star deaths and the properties of supernovae. The proximity of a newly discovered pulsar PSR J1646-4451 to a potential SNR presents a unique opportunity to study the interplay between the pulsar and its surroundings. PSR J1646-4451 was first detected as a circularly polarized source in ASKAP's VAST survey in a close proximity of a likely SNR shell. In subsequent observations with the Ultra-Wideband Low (UWL) receiver system on the Parkes radio telescope (Murriyang), the source was confirmed as a pulsar with a spin period of 217 ms and a very high dispersion measure (DM) of 930 pc cm^-3. The pulsar is highly scattered and invisible below 2 GHz, meaning that UWL is the only instrument which can be used to study this interesting pulsar. The goal of this proposal is to measure the pulsar's characteristic age by conducting follow-up timing observations in 2024APRS. Determining the characteristic age of the pulsar is the first key step to establishing evidence for or against a possible association between the pulsar and the nearby SNR.

年轻脉冲星是探究中子星早期演化阶段的核心研究对象，可为中子星的初始自转周期、运动速度与光度提供关键观测约束。若其存在于超新星遗迹（supernova remnants, SNRs）之中，则还可解析恒星死亡的普遍现象与超新星的物理属性，提供重要研究线索。新近发现的脉冲星PSR J1646-4451与一处潜在超新星遗迹距离极近，这为研究脉冲星与其周围环境的相互作用提供了独特契机。该源最初在澳大利亚平方千米阵探路者（ASKAP）的VAST巡天中被识别为圆偏振源，其位置紧邻一处疑似超新星遗迹壳层。后续利用帕克斯射电望远镜（Murriyang）的超宽带低（UWL）接收机系统开展的观测证实，该源为一颗脉冲星，其自转周期为217毫秒，色散量（dispersion measure, DM）高达930 pc cm^-3。该脉冲星散射效应极强，在2吉赫以下频段完全不可见，这意味着UWL接收机系统是目前唯一可用于研究这一特殊脉冲星的观测设备。本申请的研究目标是通过2024APRS开展的后续计时观测，测定该脉冲星的特征年龄。确定该脉冲星的特征年龄，是验证该脉冲星与附近超新星遗迹之间是否存在物理关联的首要关键步骤。