Parkes observations for project P1021 semester 2021APRS_25

We propose to continue our observations of PSR J1653-45, a 951-ms pulsar in a long, 1.5-yr orbit, which experiences apparent eclipses whose nature have yet to be fully understood. Binary pulsars are valuable objects of scientific study, allowing for multiple applications including tests of gravity, probes of the neutron star equation of state, and fossil records of stellar evolution. Long spin-period pulsars in binary systems are generally much rarer than faster-spinning `recycled’ pulsars, and represent an under-explored region of pulsar binary evolution. Based upon previous Parkes and ATCA proposals, our understanding of this pulsar has significantly increased. We have detected the pulsar in previously unexplored regions of its orbit, localised its position, and have constrained the start of the eclipse, such that a targeted campaign in the 2021APRS semester (during which the next eclipse is expected) will provide the breakthrough needed to solve and understand this pulsar. We therefore propose a high-cadence campaign with observations at least 1.4 times more sensitive than any previously recorded with Parkes during the eclipse. These observations will constrain the end of the eclipse and ensure that we detect the pulsar as early and often as possible, leading to a phase connected timing solution which will unlock the pulsar’s scientific potential. Through this, we hope to gain a greater understanding of this pulsar’s properties (as well as those of its companion) and how it fits into this under-explored class of unrecycled pulsar binaries.

本研究提议继续对脉冲星PSR J1653-45开展观测：该天体自旋周期为951毫秒，处于一条长达1.5年的长周期轨道中，且存在尚未完全探明本质的表观食现象。双星脉冲星是极具科研价值的天体，可应用于多项前沿研究，包括引力检验、中子星物态方程探测以及恒星演化化石记录分析。双星系统中的长自旋周期脉冲星，相较于自转更快的“再循环”脉冲星（recycled pulsar）要稀有得多，且属于脉冲星双星演化领域中尚未被充分探索的研究范畴。基于此前帕克斯（Parkes）望远镜与澳大利亚望远镜致密阵列（ATCA）的观测提案，我们对该脉冲星的认知已得到显著提升。我们已在该脉冲星轨道此前未被探索的区域中探测到该天体，完成了其位置精确定位，并对食相的起始时刻施加了严格约束。基于此，在2021APRS观测学期（预计将迎来下一次食相的时段）开展的针对性观测计划，将为解开该脉冲星的科学谜团提供关键突破。因此，本研究提议开展一次高观测频次的观测计划，其观测灵敏度至少比此前帕克斯望远镜在食相期间的观测灵敏度高出1.4倍。此次观测将对食相的结束时刻施加严格约束，并确保我们能够尽可能早且频繁地探测到该脉冲星，从而得到相位关联计时解，进而充分挖掘该脉冲星的科研潜力。通过此项研究，我们期望能够更深入地了解该脉冲星（及其伴星）的物理性质，以及它在这一尚未被充分探索的非再循环双星脉冲星类别中所处的演化位置。